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Module Cil


module Cil: sig .. end
CIL API Documentation. An html version of this document can be found at http://hal.cs.berkeley.edu/cil
val initCIL : unit -> unit
Call this function to perform some initialization. Call if after you have set Cil.msvcMode.
val cilVersion : string
This are the CIL version numbers. A CIL version is a number of the form M.m.r (major, minor and release)
val cilVersionMajor : int
val cilVersionMinor : int
val cilVersionRevision : int

This module defines the abstract syntax of CIL. It also provides utility functions for traversing the CIL data structures, and pretty-printing them. The parser for both the GCC and MSVC front-ends can be invoked as Frontc.parse: string -> unit -> Cil.file. This function must be given the name of a preprocessed C file and will return the top-level data structure that describes a whole source file. By default the parsing and elaboration into CIL is done as for GCC source. If you want to use MSVC source you must set the Cil.msvcMode to true and must also invoke the function Frontc.setMSVCMode: unit -> unit.

The Abstract Syntax of CIL

The top-level representation of a CIL source file (and the result of the parsing and elaboration). Its main contents is the list of global declarations and definitions. You can iterate over the globals in a Cil.file using the following iterators: Cil.mapGlobals, Cil.iterGlobals and Cil.foldGlobals. You can also use the Cil.dummyFile when you need a Cil.file as a placeholder. For each global item CIL stores the source location where it appears (using the type Cil.location)

type file = {
   mutable fileName : string; (*The complete file name*)
   mutable globals : global list; (*List of globals as they will appear in the printed file*)
   mutable globinit : fundec option; (*An optional global initializer function. This is a function where you can put stuff that must be executed before the program is started. This function, is conceptually at the end of the file, although it is not part of the globals list. Use Cil.getGlobInit to create/get one.*)
   mutable globinitcalled : bool; (*Whether the global initialization function is called in main. This should always be false if there is no global initializer. When you create a global initialization CIL will try to insert code in main to call it. This will not happen if your file does not contain a function called "main"*)
}
Top-level representation of a C source file
type comment = location * string

Globals. The main type for representing global declarations and definitions. A list of these form a CIL file. The order of globals in the file is generally important.

type global =
| GType of typeinfo * location (*A typedef. All uses of type names (through the TNamed constructor) must be preceded in the file by a definition of the name. The string is the defined name and always not-empty.*)
| GCompTag of compinfo * location (*Defines a struct/union tag with some fields. There must be one of these for each struct/union tag that you use (through the TComp constructor) since this is the only context in which the fields are printed. Consequently nested structure tag definitions must be broken into individual definitions with the innermost structure defined first.*)
| GCompTagDecl of compinfo * location (*Declares a struct/union tag. Use as a forward declaration. This is printed without the fields.*)
| GEnumTag of enuminfo * location (*Declares an enumeration tag with some fields. There must be one of these for each enumeration tag that you use (through the TEnum constructor) since this is the only context in which the items are printed.*)
| GEnumTagDecl of enuminfo * location (*Declares an enumeration tag. Use as a forward declaration. This is printed without the items.*)
| GVarDecl of varinfo * location (*A variable declaration (not a definition). If the variable has a function type then this is a prototype. There can be several declarations and at most one definition for a given variable. If both forms appear then they must share the same varinfo structure. A prototype shares the varinfo with the fundec of the definition. Either has storage Extern or there must be a definition in this file*)
| GVar of varinfo * initinfo * location (*A variable definition. Can have an initializer. The initializer is updateable so that you can change it without requiring to recreate the list of globals. There can be at most one definition for a variable in an entire program. Cannot have storage Extern or function type.*)
| GFun of fundec * location (*A function definition.*)
| GAsm of string * location (*Global asm statement. These ones can contain only a template*)
| GPragma of attribute * location (*Pragmas at top level. Use the same syntax as attributes*)
| GText of string (*Some text (printed verbatim) at top level. E.g., this way you can put comments in the output.*)
A global declaration or definition

Types. A C type is represented in CIL using the type Cil.typ. Among types we differentiate the integral types (with different kinds denoting the sign and precision), floating point types, enumeration types, array and pointer types, and function types. Every type is associated with a list of attributes, which are always kept in sorted order. Use Cil.addAttribute and Cil.addAttributes to construct list of attributes. If you want to inspect a type, you should use Cil.unrollType or Cil.unrollTypeDeep to see through the uses of named types.

CIL is configured at build-time with the sizes and alignments of the underlying compiler (GCC or MSVC). CIL contains functions that can compute the size of a type (in bits) Cil.bitsSizeOf, the alignment of a type (in bytes) Cil.alignOf_int, and can convert an offset into a start and width (both in bits) using the function Cil.bitsOffset. At the moment these functions do not take into account the packed attributes and pragmas.

type typ =
| TVoid of attributes (*Void type. Also predefined as Cil.voidType*)
| TInt of ikind * attributes (*An integer type. The kind specifies the sign and width. Several useful variants are predefined as Cil.intType, Cil.uintType, Cil.longType, Cil.charType.*)
| TFloat of fkind * attributes (*A floating-point type. The kind specifies the precision. You can also use the predefined constant Cil.doubleType.*)
| TPtr of typ * attributes (*Pointer type. Several useful variants are predefined as Cil.charPtrType, Cil.charConstPtrType (pointer to a constant character), Cil.voidPtrType, Cil.intPtrType*)
| TArray of typ * exp option * attributes (*Array type. It indicates the base type and the array length.*)
| TFun of typ * (string * typ * attributes) list option * bool
* attributes		 (*Function type. Indicates the type of the result, the name, type and name attributes of the formal arguments (None if no arguments were specified, as in a function whose definition or prototype we have not seen; Some [] means void). Use Cil.argsToList to obtain a list of arguments. The boolean indicates if it is a variable-argument function. If this is the type of a varinfo for which we have a function declaration then the information for the formals must match that in the function's sformals. Use Cil.setFormals, or Cil.setFunctionType, or Cil.makeFormalVar for this purpose.*)
| TNamed of typeinfo * attributes (*The use of a named type. Each such type name must be preceded in the file by a GType global. This is printed as just the type name. The actual referred type is not printed here and is carried only to simplify processing. To see through a sequence of named type references, use Cil.unrollType or Cil.unrollTypeDeep. The attributes are in addition to those given when the type name was defined.*)
| TComp of compinfo * attributes (*The most delicate issue for C types is that recursion that is possible by using structures and pointers. To address this issue we have a more complex representation for structured types (struct and union). Each such type is represented using the Cil.compinfo type. For each composite type the Cil.compinfo structure must be declared at top level using GCompTag and all references to it must share the same copy of the structure. The attributes given are those pertaining to this use of the type and are in addition to the attributes that were given at the definition of the type and which are stored in the Cil.compinfo.*)
| TEnum of enuminfo * attributes (*A reference to an enumeration type. All such references must share the enuminfo among them and with a GEnumTag global that precedes all uses. The attributes refer to this use of the enumeration and are in addition to the attributes of the enumeration itself, which are stored inside the enuminfo*)
| TBuiltin_va_list of attributes (*This is the same as the gcc's type with the same name*)

There are a number of functions for querying the kind of a type. These are Cil.isIntegralType, Cil.isArithmeticType, Cil.isPointerType, Cil.isFunctionType, Cil.isArrayType.

There are two easy ways to scan a type. First, you can use the Cil.existsType to return a boolean answer about a type. This function is controlled by a user-provided function that is queried for each type that is used to construct the current type. The function can specify whether to terminate the scan with a boolean result or to continue the scan for the nested types.

The other method for scanning types is provided by the visitor interface (see Cil.cilVisitor).

If you want to compare types (or to use them as hash-values) then you should use instead type signatures (represented as Cil.typsig). These contain the same information as types but canonicalized such that simple Ocaml structural equality will tell whether two types are equal. Use Cil.typeSig to compute the signature of a type. If you want to ignore certain type attributes then use Cil.typeSigWithAttrs.

type ikind =
| IChar (*char*)
| ISChar (*signed char*)
| IUChar (*unsigned char*)
| IInt (*int*)
| IUInt (*unsigned int*)
| IShort (*short*)
| IUShort (*unsigned short*)
| ILong (*long*)
| IULong (*unsigned long*)
| ILongLong (*long long (or _int64 on Microsoft Visual C)*)
| IULongLong (*unsigned long long (or unsigned _int64 on Microsoft Visual C)*)

Various kinds of integers

type fkind =
| FFloat (*float*)
| FDouble (*double*)
| FLongDouble (*long double*)
Various kinds of floating-point numbers

Attributes.

type attribute =
| Attr of string * attrparam list (*An attribute has a name and some optional parameters. The name should not start or end with underscore. When CIL parses attribute names it will strip leading and ending underscores (to ensure that the multitude of GCC attributes such as const, __const and __const__ all mean the same thing.)*) 
type attributes = attribute list
Attributes are lists sorted by the attribute name. Use the functions Cil.addAttribute and Cil.addAttributes to insert attributes in an attribute list and maintain the sortedness.

type attrparam =
| AInt of int (*An integer constant*)
| AStr of string (*A string constant*)
| ACons of string * attrparam list (*Constructed attributes. These are printed foo(a1,a2,...,an). The list of parameters can be empty and in that case the parentheses are not printed.*)
| ASizeOf of typ (*A way to talk about types*)
| ASizeOfE of attrparam
| ASizeOfS of typsig (*Replacement for ASizeOf in type signatures. Only used for attributes inside typsigs.*)
| AAlignOf of typ
| AAlignOfE of attrparam
| AAlignOfS of typsig
| AUnOp of unop * attrparam
| ABinOp of binop * attrparam * attrparam
| ADot of attrparam * string (*a.foo **)
| AStar of attrparam (* a*)
| AAddrOf of attrparam (*& a **)
| AIndex of attrparam * attrparam (*a1a2*)
| AQuestion of attrparam * attrparam * attrparam (*a1 ? a2 : a3 **)
The type of parameters of attributes

Structures. The Cil.compinfo describes the definition of a structure or union type. Each such Cil.compinfo must be defined at the top-level using the GCompTag constructor and must be shared by all references to this type (using either the TComp type constructor or from the definition of the fields.

If all you need is to scan the definition of each composite type once, you can do that by scanning all top-level GCompTag.

Constructing a Cil.compinfo can be tricky since it must contain fields that might refer to the host Cil.compinfo and furthermore the type of the field might need to refer to the Cil.compinfo for recursive types. Use the Cil.mkCompInfo function to create a Cil.compinfo. You can easily fetch the Cil.fieldinfo for a given field in a structure with Cil.getCompField.

type compinfo = {
   mutable cstruct : bool; (*True if struct, False if union*)
   mutable cname : string; (*The name. Always non-empty. Use Cil.compFullName to get the full name of a comp (along with the struct or union)*)
   mutable ckey : int; (*A unique integer. This is assigned by Cil.mkCompInfo using a global variable in the Cil module. Thus two identical structs in two different files might have different keys. Use Cil.copyCompInfo to copy structures so that a new key is assigned.*)
   mutable cfields : fieldinfo list; (*Information about the fields. Notice that each fieldinfo has a pointer back to the host compinfo. This means that you should not share fieldinfo's between two compinfo's*)
   mutable cattr : attributes; (*The attributes that are defined at the same time as the composite type. These attributes can be supplemented individually at each reference to this compinfo using the TComp type constructor.*)
   mutable cdefined : bool; (*This boolean flag can be used to distinguish between structures that have not been defined and those that have been defined but have no fields (such things are allowed in gcc).*)
   mutable creferenced : bool; (*True if used. Initially set to false.*)
}

The definition of a structure or union type. Use Cil.mkCompInfo to make one and use Cil.copyCompInfo to copy one (this ensures that a new key is assigned and that the fields have the right pointers to parents.).

Structure fields. The Cil.fieldinfo structure is used to describe a structure or union field. Fields, just like variables, can have attributes associated with the field itself or associated with the type of the field (stored along with the type of the field).

type fieldinfo = {
   mutable fcomp : compinfo; (*The host structure that contains this field. There can be only one compinfo that contains the field.*)
   mutable fname : string; (*The name of the field. Might be the value of Cil.missingFieldName in which case it must be a bitfield and is not printed and it does not participate in initialization*)
   mutable ftype : typ; (*The type*)
   mutable fbitfield : int option; (*If a bitfield then ftype should be an integer type and the width of the bitfield must be 0 or a positive integer smaller or equal to the width of the integer type. A field of width 0 is used in C to control the alignment of fields.*)
   mutable fattr : attributes; (*The attributes for this field (not for its type)*)
   mutable floc : location; (*The location where this field is defined*)
}
Information about a struct/union field

Enumerations. Information about an enumeration. This is shared by all references to an enumeration. Make sure you have a GEnumTag for each of of these.

type enuminfo = {
   mutable ename : string; (*The name. Always non-empty.*)
   mutable eitems : (string * exp * location) list; (*Items with names and values. This list should be non-empty. The item values must be compile-time constants.*)
   mutable eattr : attributes; (*The attributes that are defined at the same time as the enumeration type. These attributes can be supplemented individually at each reference to this enuminfo using the TEnum type constructor.*)
   mutable ereferenced : bool; (*True if used. Initially set to false*)
}
Information about an enumeration

Enumerations. Information about an enumeration. This is shared by all references to an enumeration. Make sure you have a GEnumTag for each of of these.

type typeinfo = {
   mutable tname : string; (*The name. Can be empty only in a GType when introducing a composite or enumeration tag. If empty cannot be referred to from the file*)
   mutable ttype : typ; (*The actual type. This includes the attributes that were present in the typedef*)
   mutable treferenced : bool; (*True if used. Initially set to false*)
}
Information about a defined type

Variables. Each local or global variable is represented by a unique Cil.varinfo structure. A global Cil.varinfo can be introduced with the GVarDecl or GVar or GFun globals. A local varinfo can be introduced as part of a function definition Cil.fundec.

All references to a given global or local variable must refer to the same copy of the varinfo. Each varinfo has a globally unique identifier that can be used to index maps and hashtables (the name can also be used for this purpose, except for locals from different functions). This identifier is constructor using a global counter.

It is very important that you construct varinfo structures using only one of the following functions:

A varinfo is also used in a function type to denote the list of formals.

type varinfo = {
   mutable vname : string; (*The name of the variable. Cannot be empty. It is primarily your responsibility to ensure the uniqueness of a variable name. For local variables Cil.makeTempVar helps you ensure that the name is unique.*)
   mutable vtype : typ; (*The declared type of the variable.*)
   mutable vattr : attributes; (*A list of attributes associated with the variable.*)
   mutable vstorage : storage; (*The storage-class*)
   mutable vglob : bool; (*True if this is a global variable*)
   mutable vinline : bool; (*Whether this varinfo is for an inline function.*)
   mutable vdecl : location; (*Location of variable declaration.*)
   mutable vid : int; (*A unique integer identifier. This field will be set for you if you use one of the Cil.makeFormalVar, Cil.makeLocalVar, Cil.makeTempVar, Cil.makeGlobalVar, or Cil.copyVarinfo.*)
   mutable vaddrof : bool; (*True if the address of this variable is taken. CIL will set these flags when it parses C, but you should make sure to set the flag whenever your transformation create AddrOf expression.*)
   mutable vreferenced : bool; (*True if this variable is ever referenced. This is computed by removeUnusedVars. It is safe to just initialize this to False*)
   mutable vdescr : Pretty.doc; (*For most temporary variables, a description of what the var holds. (e.g. for temporaries used for function call results, this string is a representation of the function call.)*)
   mutable vdescrpure : bool; (*Indicates whether the vdescr above is a pure expression or call. Printing a non-pure vdescr more than once may yield incorrect results.*)
}
Information about a variable.

type storage =
| NoStorage (*The default storage. Nothing is printed*)
| Static
| Register
| Extern
Storage-class information

Expressions. The CIL expression language contains only the side-effect free expressions of C. They are represented as the type Cil.exp. There are several interesting aspects of CIL expressions:

Integer and floating point constants can carry their textual representation. This way the integer 15 can be printed as 0xF if that is how it occurred in the source.

CIL uses 64 bits to represent the integer constants and also stores the width of the integer type. Care must be taken to ensure that the constant is representable with the given width. Use the functions Cil.kinteger, Cil.kinteger64 and Cil.integer to construct constant expressions. CIL predefines the constants Cil.zero, Cil.one and Cil.mone (for -1).

Use the functions Cil.isConstant and Cil.isInteger to test if an expression is a constant and a constant integer respectively.

CIL keeps the type of all unary and binary expressions. You can think of that type qualifying the operator. Furthermore there are different operators for arithmetic and comparisons on arithmetic types and on pointers.

Another unusual aspect of CIL is that the implicit conversion between an expression of array type and one of pointer type is made explicit, using the StartOf expression constructor (which is not printed). If you apply the AddrOf}constructor to an lvalue of type T then you will be getting an expression of type TPtr(T).

You can find the type of an expression with Cil.typeOf.

You can perform constant folding on expressions using the function Cil.constFold.

type exp =
| Const of constant (*Constant*)
| Lval of lval (*Lvalue*)
| SizeOf of typ (*sizeof(<type>). Has unsigned int type (ISO 6.5.3.4). This is not turned into a constant because some transformations might want to change types*)
| SizeOfE of exp (*sizeof(<expression>)*)
| SizeOfStr of string (*sizeof(string_literal). We separate this case out because this is the only instance in which a string literal should not be treated as having type pointer to character.*)
| AlignOf of typ (*This corresponds to the GCC __alignof_. Has unsigned int type*)
| AlignOfE of exp
| UnOp of unop * exp * typ (*Unary operation. Includes the type of the result.*)
| BinOp of binop * exp * exp * typ (*Binary operation. Includes the type of the result. The arithmetic conversions are made explicit for the arguments.*)
| CastE of typ * exp (*Use Cil.mkCast to make casts.*)
| AddrOf of lval (*Always use Cil.mkAddrOf to construct one of these. Apply to an lvalue of type T yields an expression of type TPtr(T). Use Cil.mkAddrOrStartOf to make one of these if you are not sure which one to use.*)
| StartOf of lval (*Conversion from an array to a pointer to the beginning of the array. Given an lval of type TArray(T) produces an expression of type TPtr(T). Use Cil.mkAddrOrStartOf to make one of these if you are not sure which one to use. In C this operation is implicit, the StartOf operator is not printed. We have it in CIL because it makes the typing rules simpler.*)

Expressions (Side-effect free)

Constants.

type constant =
| CInt64 of int64 * ikind * string option (*Integer constant. Give the ikind (see ISO9899 6.1.3.2) and the textual representation, if available. (This allows us to print a constant as, for example, 0xF instead of 15.) Use Cil.integer or Cil.kinteger to create these. Watch out for integers that cannot be represented on 64 bits. OCAML does not give Overflow exceptions.*)
| CStr of string (*String constant. The escape characters inside the string have been already interpreted. This constant has pointer to character type! The only case when you would like a string literal to have an array type is when it is an argument to sizeof. In that case you should use SizeOfStr.*)
| CWStr of int64 list (*Wide character string constant. Note that the local interpretation of such a literal depends on Cil.wcharType and Cil.wcharKind. Such a constant has type pointer to Cil.wcharType. The escape characters in the string have not been "interpreted" in the sense that L"A\xabcd" remains "A\xabcd" rather than being represented as the wide character list with two elements: 65 and 43981. That "interpretation" depends on the underlying wide character type.*)
| CChr of char (*Character constant. This has type int, so use charConstToInt to read the value in case sign-extension is needed.*)
| CReal of float * fkind * string option (*Floating point constant. Give the fkind (see ISO 6.4.4.2) and also the textual representation, if available.*)
| CEnum of exp * string * enuminfo (*An enumeration constant with the given value, name, from the given enuminfo. This is used only if Cil.lowerConstants is true (default). Use Cil.constFoldVisitor to replace these with integer constants.*)
Literal constants

type unop =
| Neg (*Unary minus*)
| BNot (*Bitwise complement (~)*)
| LNot (*Logical Not (!)*)
Unary operators

type binop =
| PlusA (*arithmetic +*)
| PlusPI (*pointer + integer*)
| IndexPI (*pointer + integer but only when it arises from an expression e[i] when e is a pointer and not an array. This is semantically the same as PlusPI but CCured uses this as a hint that the integer is probably positive.*)
| MinusA (*arithmetic -*)
| MinusPI (*pointer - integer*)
| MinusPP (*pointer - pointer*)
| Mult
| Div (*/*)
| Mod (*%*)
| Shiftlt (*shift left*)
| Shiftrt (*shift right*)
| Lt (*< (arithmetic comparison)*)
| Gt (*> (arithmetic comparison)*)
| Le (*<= (arithmetic comparison)*)
| Ge (*> (arithmetic comparison)*)
| Eq (*== (arithmetic comparison)*)
| Ne (*!= (arithmetic comparison)*)
| BAnd (*bitwise and*)
| BXor (*exclusive-or*)
| BOr (*inclusive-or*)
| LAnd (*logical and. Unlike other expressions this one does not always evaluate both operands. If you want to use these, you must set Cil.useLogicalOperators.*)
| LOr (*logical or. Unlike other expressions this one does not always evaluate both operands. If you want to use these, you must set Cil.useLogicalOperators.*)
Binary operations

Lvalues. Lvalues are the sublanguage of expressions that can appear at the left of an assignment or as operand to the address-of operator. In C the syntax for lvalues is not always a good indication of the meaning of the lvalue. For example the C value 
 
a[0][1][2]
might involve 1, 2 or 3 memory reads when used in an expression context, depending on the declared type of the variable a. If a has type int [4][4][4] then we have one memory read from somewhere inside the area that stores the array a. On the other hand if a has type int *** then the expression really means * ( * ( * (a + 0) + 1) + 2), in which case it is clear that it involves three separate memory operations.

An lvalue denotes the contents of a range of memory addresses. This range is denoted as a host object along with an offset within the object. The host object can be of two kinds: a local or global variable, or an object whose address is in a pointer expression. We distinguish the two cases so that we can tell quickly whether we are accessing some component of a variable directly or we are accessing a memory location through a pointer. To make it easy to tell what an lvalue means CIL represents lvalues as a host object and an offset (see Cil.lval). The host object (represented as Cil.lhost) can be a local or global variable or can be the object pointed-to by a pointer expression. The offset (represented as Cil.offset) is a sequence of field or array index designators.

Both the typing rules and the meaning of an lvalue is very precisely specified in CIL.

The following are a few useful function for operating on lvalues:

The following equivalences hold 
Mem(AddrOf(Mem a, aoff)), off   = Mem a, aoff + off 
Mem(AddrOf(Var v, aoff)), off   = Var v, aoff + off 
AddrOf (Mem a, NoOffset)        = a                 


type lval = lhost * offset
An lvalue

type lhost =
| Var of varinfo (*The host is a variable.*)
| Mem of exp (*The host is an object of type T when the expression has pointer TPtr(T).*)
The host part of an Cil.lval.

type offset =
| NoOffset (*No offset. Can be applied to any lvalue and does not change either the starting address or the type. This is used when the lval consists of just a host or as a terminator in a list of other kinds of offsets.*)
| Field of fieldinfo * offset (*A field offset. Can be applied only to an lvalue that denotes a structure or a union that contains the mentioned field. This advances the offset to the beginning of the mentioned field and changes the type to the type of the mentioned field.*)
| Index of exp * offset (*An array index offset. Can be applied only to an lvalue that denotes an array. This advances the starting address of the lval to the beginning of the mentioned array element and changes the denoted type to be the type of the array element*)
The offset part of an Cil.lval. Each offset can be applied to certain kinds of lvalues and its effect is that it advances the starting address of the lvalue and changes the denoted type, essentially focusing to some smaller lvalue that is contained in the original one.

Initializers. A special kind of expressions are those that can appear as initializers for global variables (initialization of local variables is turned into assignments). The initializers are represented as type Cil.init. You can create initializers with Cil.makeZeroInit and you can conveniently scan compound initializers them with Cil.foldLeftCompound.

type init =
| SingleInit of exp (*A single initializer*)
| CompoundInit of typ * (offset * init) list (*Used only for initializers of structures, unions and arrays. The offsets are all of the form Field(f, NoOffset) or Index(i, NoOffset) and specify the field or the index being initialized. For structures all fields must have an initializer (except the unnamed bitfields), in the proper order. This is necessary since the offsets are not printed. For unions there must be exactly one initializer. If the initializer is not for the first field then a field designator is printed, so you better be on GCC since MSVC does not understand this. For arrays, however, we allow you to give only a prefix of the initializers. You can scan an initializer list with Cil.foldLeftCompound.*)
Initializers for global variables.

type initinfo = {
   mutable init : init option;
}
We want to be able to update an initializer in a global variable, so we define it as a mutable field

Function definitions. A function definition is always introduced with a GFun constructor at the top level. All the information about the function is stored into a Cil.fundec. Some of the information (e.g. its name, type, storage, attributes) is stored as a Cil.varinfo that is a field of the fundec. To refer to the function from the expression language you must use the varinfo.

The function definition contains, in addition to the body, a list of all the local variables and separately a list of the formals. Both kind of variables can be referred to in the body of the function. The formals must also be shared with the formals that appear in the function type. For that reason, to manipulate formals you should use the provided functions Cil.makeFormalVar and Cil.setFormals and Cil.makeFormalVar.

type fundec = {
   mutable svar : varinfo; (*Holds the name and type as a variable, so we can refer to it easily from the program. All references to this function either in a function call or in a prototype must point to the same varinfo.*)
   mutable sformals : varinfo list; (*Formals. These must be in the same order and with the same information as the formal information in the type of the function. Use Cil.setFormals or Cil.setFunctionType or Cil.makeFormalVar to set these formals and ensure that they are reflected in the function type. Do not make copies of these because the body refers to them.*)
   mutable slocals : varinfo list; (*Locals. Does NOT include the sformals. Do not make copies of these because the body refers to them.*)
   mutable smaxid : int; (*Max local id. Starts at 0. Used for creating the names of new temporary variables. Updated by Cil.makeLocalVar and Cil.makeTempVar. You can also use Cil.setMaxId to set it after you have added the formals and locals.*)
   mutable sbody : block; (*The function body.*)
   mutable smaxstmtid : int option; (*max id of a (reachable) statement in this function, if we have computed it. range = 0 ... (smaxstmtid-1). This is computed by Cil.computeCFGInfo.*)
   mutable sallstmts : stmt list; (*After you call Cil.computeCFGInfo this field is set to contain all statements in the function*)
}

Function definitions.

type block = {
   mutable battrs : attributes; (*Attributes for the block*)
   mutable bstmts : stmt list; (*The statements comprising the block*)
}
A block is a sequence of statements with the control falling through from one element to the next

Statements. CIL statements are the structural elements that make the CFG. They are represented using the type Cil.stmt. Every statement has a (possibly empty) list of labels. The Cil.stmtkind field of a statement indicates what kind of statement it is.

Use Cil.mkStmt to make a statement and the fill-in the fields.

CIL also comes with support for control-flow graphs. The sid field in stmt can be used to give unique numbers to statements, and the succs and preds fields can be used to maintain a list of successors and predecessors for every statement. The CFG information is not computed by default. Instead you must explicitly use the functions Cil.prepareCFG and Cil.computeCFGInfo to do it.

type stmt = {
   mutable labels : label list; (*Whether the statement starts with some labels, case statements or default statements.*)
   mutable skind : stmtkind; (*The kind of statement*)
   mutable sid : int; (*A number (>= 0) that is unique in a function. Filled in only after the CFG is computed.*)
   mutable succs : stmt list; (*The successor statements. They can always be computed from the skind and the context in which this statement appears. Filled in only after the CFG is computed.*)
   mutable preds : stmt list; (*The inverse of the succs function.*)
}

Statements.

type label =
| Label of string * location * bool (*A real label. If the bool is "true", the label is from the input source program. If the bool is "false", the label was created by CIL or some other transformation*)
| Case of exp * location (*A case statement. This expression is lowered into a constant if Cil.lowerConstants is set to true.*)
| Default of location (*A default statement*)
Labels

type stmtkind =
| Instr of instr list (*A group of instructions that do not contain control flow. Control implicitly falls through.*)
| Return of exp option * location (*The return statement. This is a leaf in the CFG.*)
| Goto of stmt ref * location (*A goto statement. Appears from actual goto's in the code or from goto's that have been inserted during elaboration. The reference points to the statement that is the target of the Goto. This means that you have to update the reference whenever you replace the target statement. The target statement MUST have at least a label.*)
| Break of location (*A break to the end of the nearest enclosing Loop or Switch*)
| Continue of location (*A continue to the start of the nearest enclosing Loop*)
| If of exp * block * block * location (*A conditional. Two successors, the "then" and the "else" branches. Both branches fall-through to the successor of the If statement.*)
| Switch of exp * block * stmt list * location (*A switch statement. The statements that implement the cases can be reached through the provided list. For each such target you can find among its labels what cases it implements. The statements that implement the cases are somewhere within the provided block.*)
| Loop of block * location * stmt option * stmt option (*A while(1) loop. The termination test is implemented in the body of a loop using a Break statement. If prepareCFG has been called, the first stmt option will point to the stmt containing the continue label for this loop and the second will point to the stmt containing the break label for this loop.*)
| Block of block (*Just a block of statements. Use it as a way to keep some block attributes local*)
| TryFinally of block * block * location
| TryExcept of block * (instr list * exp) * block * location
The various kinds of control-flow statements statements

Instructions. An instruction Cil.instr is a statement that has no local (intraprocedural) control flow. It can be either an assignment, function call, or an inline assembly instruction.

type instr =
| Set of lval * exp * location (*An assignment. The type of the expression is guaranteed to be the same with that of the lvalue*)
| Call of lval option * exp * exp list * location (*A function call with the (optional) result placed in an lval. It is possible that the returned type of the function is not identical to that of the lvalue. In that case a cast is printed. The type of the actual arguments are identical to those of the declared formals. The number of arguments is the same as that of the declared formals, except for vararg functions. This construct is also used to encode a call to "__builtin_va_arg". In this case the second argument (which should be a type T) is encoded SizeOf(T)*)
| Asm of attributes * string list * (string option * string * lval) list
* (string option * string * exp) list * string list * location		 (*There are for storing inline assembly. They follow the GCC specification: 
  asm [volatile] ("...template..." "..template.."
                  : "c1" (o1), "c2" (o2), ..., "cN" (oN)
                  : "d1" (i1), "d2" (i2), ..., "dM" (iM)
                  : "r1", "r2", ..., "nL" );

where the parts are

  • volatile (optional): when present, the assembler instruction cannot be removed, moved, or otherwise optimized
  • template: a sequence of strings, with %0, %1, %2, etc. in the string to refer to the input and output expressions. I think they're numbered consecutively, but the docs don't specify. Each string is printed on a separate line. This is the only part that is present for MSVC inline assembly.
  • "ci" (oi): pairs of constraint-string and output-lval; the constraint specifies that the register used must have some property, like being a floating-point register; the constraint string for outputs also has "=" to indicate it is written, or "+" to indicate it is both read and written; 'oi' is the name of a C lvalue (probably a variable name) to be used as the output destination
  • "dj" (ij): pairs of constraint and input expression; the constraint is similar to the "ci"s. the 'ij' is an arbitrary C expression to be loaded into the corresponding register
  • "rk": registers to be regarded as "clobbered" by the instruction; "memory" may be specified for arbitrary memory effects
an example (from gcc manual): 
  asm volatile ("movc3 %0,%1,%2"
                : /* no outputs */
                : "g" (from), "g" (to), "g" (count)
                : "r0", "r1", "r2", "r3", "r4", "r5");

Starting with gcc 3.1, the operands may have names: 

  asm volatile ("movc3 %[in0],%1,%2"
                : /* no outputs */
                : [in0] "g" (from), "g" (to), "g" (count)
                : "r0", "r1", "r2", "r3", "r4", "r5");
*)
Instructions.

type location = {
   line : int; (*The line number. -1 means "do not know"*)
   file : string; (*The name of the source file*)
   byte : int; (*The byte position in the source file*)
}
Describes a location in a source file.

type typsig =
| TSArray of typsig * int64 option * attribute list
| TSPtr of typsig * attribute list
| TSComp of bool * string * attribute list
| TSFun of typsig * typsig list * bool * attribute list
| TSEnum of string * attribute list
| TSBase of typ
Type signatures. Two types are identical iff they have identical signatures. These contain the same information as types but canonicalized. For example, two function types that are identical except for the name of the formal arguments are given the same signature. Also, TNamed constructors are unrolled.

Lowering Options
val lowerConstants : bool ref
Do lower constants (default true)
val insertImplicitCasts : bool ref
Do insert implicit casts (default true)

type featureDescr = {
   fd_enabled : bool ref; (*The enable flag. Set to default value*)
   fd_name : string; (*This is used to construct an option "--doxxx" and "--dontxxx" that enable and disable the feature*)
   fd_description : string; (*A longer name that can be used to document the new options*)
   fd_extraopt : (string * Arg.spec * string) list; (*Additional command line options. The description strings should usually start with a space for Arg.align to print the --help nicely.*)
   fd_doit : file -> unit; (*This performs the transformation*)
   fd_post_check : bool; (*Whether to perform a CIL consistency checking after this stage, if checking is enabled (--check is passed to cilly). Set this to true if your feature makes any changes for the program.*)
}
To be able to add/remove features easily, each feature should be package as an interface with the following interface. These features should be
val compareLoc : location -> location -> int
Comparison function for locations. * Compares first by filename, then line, then byte

Values for manipulating globals
val emptyFunction : string -> fundec
Make an empty function
val setFormals : fundec -> varinfo list -> unit
Update the formals of a fundec and make sure that the function type has the same information. Will copy the name as well into the type.
val setFunctionType : fundec -> typ -> unit
Set the types of arguments and results as given by the function type passed as the second argument. Will not copy the names from the function type to the formals
val setFunctionTypeMakeFormals : fundec -> typ -> unit
Set the type of the function and make formal arguments for them
val setMaxId : fundec -> unit
Update the smaxid after you have populated with locals and formals (unless you constructed those using Cil.makeLocalVar or Cil.makeTempVar.
val dummyFunDec : fundec
A dummy function declaration handy when you need one as a placeholder. It contains inside a dummy varinfo.
val dummyFile : file
A dummy file
val saveBinaryFile : file -> string -> unit
Write a Cil.file in binary form to the filesystem. The file can be read back in later using Cil.loadBinaryFile, possibly saving parsing time. The second argument is the name of the file that should be created.
val saveBinaryFileChannel : file -> out_channel -> unit
Write a Cil.file in binary form to the filesystem. The file can be read back in later using Cil.loadBinaryFile, possibly saving parsing time. Does not close the channel.
val loadBinaryFile : string -> file
Read a Cil.file in binary form from the filesystem. The first argument is the name of a file previously created by Cil.saveBinaryFile. Because this also reads some global state, this should be called before any other CIL code is parsed or generated.
val getGlobInit : ?main_name:string -> file -> fundec
Get the global initializer and create one if it does not already exist. When it creates a global initializer it attempts to place a call to it in the main function named by the optional argument (default "main")
val iterGlobals : file -> (global -> unit) -> unit
Iterate over all globals, including the global initializer
val foldGlobals : file -> ('a -> global -> 'a) -> 'a -> 'a
Fold over all globals, including the global initializer
val mapGlobals : file -> (global -> global) -> unit
Map over all globals, including the global initializer and change things in place
val findOrCreateFunc : file -> string -> typ -> varinfo
Find a function or function prototype with the given name in the file. If it does not exist, create a prototype with the given type, and return the new varinfo. This is useful when you need to call a libc function whose prototype may or may not already exist in the file.

Because the new prototype is added to the start of the file, you shouldn't refer to any struct or union types in the function type.

val new_sid : unit -> int
val prepareCFG : fundec -> unit
Prepare a function for CFG information computation by Cil.computeCFGInfo. This function converts all Break, Switch, Default and Continue Cil.stmtkinds and Cil.labels into Ifs and Gotos, giving the function body a very CFG-like character. This function modifies its argument in place.
val computeCFGInfo : fundec -> bool -> unit
Compute the CFG information for all statements in a fundec and return a list of the statements. The input fundec cannot have Break, Switch, Default, or Continue Cil.stmtkinds or Cil.labels. Use Cil.prepareCFG to transform them away. The second argument should be true if you wish a global statement number, false if you wish a local (per-function) statement numbering. The list of statements is set in the sallstmts field of a fundec.

NOTE: unless you want the simpler control-flow graph provided by prepareCFG, or you need the function's smaxstmtid and sallstmt fields filled in, we recommend you use Cfg.computeFileCFG instead of this function to compute control-flow information. Cfg.computeFileCFG is newer and will handle switch, break, and continue correctly.

val copyFunction : fundec -> string -> fundec
Create a deep copy of a function. There should be no sharing between the copy and the original function
val pushGlobal : global ->
       types:global list ref ->
       variables:global list ref -> unit
CIL keeps the types at the beginning of the file and the variables at the end of the file. This function will take a global and add it to the corresponding stack. Its operation is actually more complicated because if the global declares a type that contains references to variables (e.g. in sizeof in an array length) then it will also add declarations for the variables to the types stack
val invalidStmt : stmt
An empty statement. Used in pretty printing
val builtinFunctions : (string, typ * typ list * bool) Hashtbl.t
A list of the built-in functions for the current compiler (GCC or MSVC, depending on !msvcMode). Maps the name to the result and argument types, and whether it is vararg. Initialized by Cil.initCIL

This map replaces gccBuiltins and msvcBuiltins in previous versions of CIL.

val gccBuiltins : (string, typ * typ list * bool) Hashtbl.t
Deprecated.. For compatibility with older programs, these are aliases for Cil.builtinFunctions
val msvcBuiltins : (string, typ * typ list * bool) Hashtbl.t
Deprecated.. For compatibility with older programs, these are aliases for Cil.builtinFunctions
val builtinLoc : location
This is used as the location of the prototypes of builtin functions.

Values for manipulating initializers
val makeZeroInit : typ -> init
Make a initializer for zero-ing a data type
val foldLeftCompound : implicit:bool ->
       doinit:(offset -> init -> typ -> 'a -> 'a) ->
       ct:typ -> initl:(offset * init) list -> acc:'a -> 'a
Fold over the list of initializers in a Compound (not also the nested ones). doinit is called on every present initializer, even if it is of compound type. The parameters of doinit are: the offset in the compound (this is Field(f,NoOffset) or Index(i,NoOffset)), the initializer value, expected type of the initializer value, accumulator. In the case of arrays there might be missing zero-initializers at the end of the list. These are scanned only if implicit is true. This is much like List.fold_left except we also pass the type of the initializer.

This is a good way to use it to scan even nested initializers : 

  let rec myInit (lv: lval) (i: init) (acc: 'a) : 'a = 
      match i with 
        SingleInit e -> ... do something with lv and e and acc ...
      | CompoundInit (ct, initl) ->  
         foldLeftCompound ~implicit:false
             ~doinit:(fun off' i' t' acc -> 
                        myInit (addOffsetLval lv off') i' acc)
             ~ct:ct
             ~initl:initl
             ~acc:acc


Values for manipulating types
val voidType : typ
void
val isVoidType : typ -> bool
is the given type "void"?
val isVoidPtrType : typ -> bool
is the given type "void *"?
val intType : typ
int
val uintType : typ
unsigned int
val longType : typ
long
val ulongType : typ
unsigned long
val charType : typ
char
val charPtrType : typ
char *
val wcharKind : ikind ref
wchar_t (depends on architecture) and is set when you call Cil.initCIL.
val wcharType : typ ref
val charConstPtrType : typ
char const *
val voidPtrType : typ
void *
val intPtrType : typ
int *
val uintPtrType : typ
unsigned int *
val doubleType : typ
double
val upointType : typ ref
An unsigned integer type that fits pointers. Depends on Cil.msvcMode and is set when you call Cil.initCIL.
val typeOfSizeOf : typ ref
An unsigned integer type that is the type of sizeof. Depends on Cil.msvcMode and is set when you call Cil.initCIL.
val kindOfSizeOf : ikind ref
The integer kind of Cil.typeOfSizeOf. Set when you call Cil.initCIL.
val isSigned : ikind -> bool
Returns true if and only if the given integer type is signed.
val mkCompInfo : bool ->
       string ->
       (compinfo ->
        (string * typ * int option * attributes * location) list) ->
       attributes -> compinfo
Creates a a (potentially recursive) composite type. The arguments are: (1) a boolean indicating whether it is a struct or a union, (2) the name (always non-empty), (3) a function that when given a representation of the structure type constructs the type of the fields recursive type (the first argument is only useful when some fields need to refer to the type of the structure itself), and (4) a list of attributes to be associated with the composite type. The resulting compinfo has the field "cdefined" only if the list of fields is non-empty.
val copyCompInfo : compinfo -> string -> compinfo
Makes a shallow copy of a Cil.compinfo changing the name and the key.
val missingFieldName : string
This is a constant used as the name of an unnamed bitfield. These fields do not participate in initialization and their name is not printed.
val compFullName : compinfo -> string
Get the full name of a comp
val isCompleteType : typ -> bool
Returns true if this is a complete type. This means that sizeof(t) makes sense. Incomplete types are not yet defined structures and empty arrays.
val unrollType : typ -> typ
Unroll a type until it exposes a non TNamed. Will collect all attributes appearing in TNamed!!!
val unrollTypeDeep : typ -> typ
Unroll all the TNamed in a type (even under type constructors such as TPtr, TFun or TArray. Does not unroll the types of fields in TComp types. Will collect all attributes
val separateStorageModifiers : attribute list -> attribute list * attribute list
Separate out the storage-modifier name attributes
val isIntegralType : typ -> bool
True if the argument is an integral type (i.e. integer or enum)
val isArithmeticType : typ -> bool
True if the argument is an arithmetic type (i.e. integer, enum or floating point
val isPointerType : typ -> bool
True if the argument is a pointer type
val isFunctionType : typ -> bool
True if the argument is a function type
val argsToList : (string * typ * attributes) list option ->
       (string * typ * attributes) list
Obtain the argument list ([] if None)
val isArrayType : typ -> bool
True if the argument is an array type
exception LenOfArray
Raised when Cil.lenOfArray fails either because the length is None or because it is a non-constant expression
val lenOfArray : exp option -> int
Call to compute the array length as present in the array type, to an integer. Raises Cil.LenOfArray if not able to compute the length, such as when there is no length or the length is not a constant.
val getCompField : compinfo -> string -> fieldinfo
Return a named fieldinfo in compinfo, or raise Not_found

type existsAction =
| ExistsTrue (*We have found it*)
| ExistsFalse (*Stop processing this branch*)
| ExistsMaybe (*This node is not what we are looking for but maybe its successors are*)
A datatype to be used in conjunction with existsType
val existsType : (typ -> existsAction) -> typ -> bool
Scans a type by applying the function on all elements. When the function returns ExistsTrue, the scan stops with true. When the function returns ExistsFalse then the current branch is not scanned anymore. Care is taken to apply the function only once on each composite type, thus avoiding circularity. When the function returns ExistsMaybe then the types that construct the current type are scanned (e.g. the base type for TPtr and TArray, the type of fields for a TComp, etc).
val splitFunctionType : typ ->
       typ * (string * typ * attributes) list option * bool *
       attributes
Given a function type split it into return type, arguments, is_vararg and attributes. An error is raised if the type is not a function type

Same as Cil.splitFunctionType but takes a varinfo. Prints a nicer error message if the varinfo is not for a function

val splitFunctionTypeVI : varinfo ->
       typ * (string * typ * attributes) list option * bool *
       attributes

Type signatures

Type signatures. Two types are identical iff they have identical signatures. These contain the same information as types but canonicalized. For example, two function types that are identical except for the name of the formal arguments are given the same signature. Also, TNamed constructors are unrolled.
val d_typsig : unit -> typsig -> Pretty.doc
Print a type signature
val typeSig : typ -> typsig
Compute a type signature
val typeSigWithAttrs : ?ignoreSign:bool ->
       (attributes -> attributes) -> typ -> typsig
Like Cil.typeSig but customize the incorporation of attributes. Use ~ignoreSign:true to convert all signed integer types to unsigned, so that signed and unsigned will compare the same.
val setTypeSigAttrs : attributes -> typsig -> typsig
Replace the attributes of a signature (only at top level)
val typeSigAttrs : typsig -> attributes
Get the top-level attributes of a signature

LVALUES
val makeVarinfo : bool -> string -> typ -> varinfo
Make a varinfo. Use this (rarely) to make a raw varinfo. Use other functions to make locals (Cil.makeLocalVar or Cil.makeFormalVar or Cil.makeTempVar) and globals (Cil.makeGlobalVar). Note that this function will assign a new identifier. The first argument specifies whether the varinfo is for a global.
val makeFormalVar : fundec -> ?where:string -> string -> typ -> varinfo
Make a formal variable for a function. Insert it in both the sformals and the type of the function. You can optionally specify where to insert this one. If where = "^" then it is inserted first. If where = "$" then it is inserted last. Otherwise where must be the name of a formal after which to insert this. By default it is inserted at the end.
val makeLocalVar : fundec -> ?insert:bool -> string -> typ -> varinfo
Make a local variable and add it to a function's slocals (only if insert = true, which is the default). Make sure you know what you are doing if you set insert=false.
val makeTempVar : fundec ->
       ?name:string ->
       ?descr:Pretty.doc -> ?descrpure:bool -> typ -> varinfo
Make a temporary variable and add it to a function's slocals. The name of the temporary variable will be generated based on the given name hint so that to avoid conflicts with other locals. Optionally, you can give the variable a description of its contents.
val makeGlobalVar : string -> typ -> varinfo
Make a global variable. Your responsibility to make sure that the name is unique
val copyVarinfo : varinfo -> string -> varinfo
Make a shallow copy of a varinfo and assign a new identifier
val newVID : unit -> int
Generate a new variable ID. This will be different than any variable ID that is generated by Cil.makeLocalVar and friends
val addOffsetLval : offset -> lval -> lval
Add an offset at the end of an lvalue. Make sure the type of the lvalue and the offset are compatible.
val addOffset : offset -> offset -> offset
addOffset o1 o2 adds o1 to the end of o2.
val removeOffsetLval : lval -> lval * offset
Remove ONE offset from the end of an lvalue. Returns the lvalue with the trimmed offset and the final offset. If the final offset is NoOffset then the original lval did not have an offset.
val removeOffset : offset -> offset * offset
Remove ONE offset from the end of an offset sequence. Returns the trimmed offset and the final offset. If the final offset is NoOffset then the original lval did not have an offset.
val typeOfLval : lval -> typ
Compute the type of an lvalue
val typeOffset : typ -> offset -> typ
Compute the type of an offset from a base type

Values for manipulating expressions
val zero : exp
0
val one : exp
1
val mone : exp
-1
val kinteger64 : ikind -> int64 -> exp
Construct an integer of a given kind, using OCaml's int64 type. If needed it will truncate the integer to be within the representable range for the given kind.
val kinteger : ikind -> int -> exp
Construct an integer of a given kind. Converts the integer to int64 and then uses kinteger64. This might truncate the value if you use a kind that cannot represent the given integer. This can only happen for one of the Char or Short kinds
val integer : int -> exp
Construct an integer of kind IInt. You can use this always since the OCaml integers are 31 bits and are guaranteed to fit in an IInt
val isInteger : exp -> int64 option
True if the given expression is a (possibly cast'ed) character or an integer constant
val i64_to_int : int64 -> int
Convert a 64-bit int to an OCaml int, or raise an exception if that can't be done.
val isConstant : exp -> bool
True if the expression is a compile-time constant
val isZero : exp -> bool
True if the given expression is a (possibly cast'ed) integer or character constant with value zero
val charConstToInt : char -> constant
Given the character c in a (CChr c), sign-extend it to 32 bits. (This is the official way of interpreting character constants, according to ISO C 6.4.4.4.10, which says that character constants are chars cast to ints) Returns CInt64(sign-extened c, IInt, None)
val constFold : bool -> exp -> exp
Do constant folding on an expression. If the first argument is true then will also compute compiler-dependent expressions such as sizeof. See also Cil.constFoldVisitor, which will run constFold on all expressions in a given AST node.
val constFoldBinOp : bool -> binop -> exp -> exp -> typ -> exp
Do constant folding on a binary operation. The bulk of the work done by constFold is done here. If the first argument is true then will also compute compiler-dependent expressions such as sizeof
val increm : exp -> int -> exp
Increment an expression. Can be arithmetic or pointer type
val var : varinfo -> lval
Makes an lvalue out of a given variable
val mkAddrOf : lval -> exp
Make an AddrOf. Given an lvalue of type T will give back an expression of type ptr(T). It optimizes somewhat expressions like "& v" and "& v0"
val mkAddrOrStartOf : lval -> exp
Like mkAddrOf except if the type of lval is an array then it uses StartOf. This is the right operation for getting a pointer to the start of the storage denoted by lval.
val mkMem : addr:exp -> off:offset -> lval
Make a Mem, while optimizing AddrOf. The type of the addr must be TPtr(t) and the type of the resulting lval is t. Note that in CIL the implicit conversion between an array and the pointer to the first element does not apply. You must do the conversion yourself using StartOf
val mkString : string -> exp
Make an expression that is a string constant (of pointer type)
val mkCastT : e:exp -> oldt:typ -> newt:typ -> exp
Construct a cast when having the old type of the expression. If the new type is the same as the old type, then no cast is added.
val mkCast : e:exp -> newt:typ -> exp
Like Cil.mkCastT but uses typeOf to get oldt
val stripCasts : exp -> exp
Removes casts from this expression, but ignores casts within other expression constructs. So we delete the (A) and (B) casts from "(A)(B)(x + (C)y)", but leave the (C) cast.
val typeOf : exp -> typ
Compute the type of an expression
val parseInt : string -> exp
Convert a string representing a C integer literal to an expression. Handles the prefixes 0x and 0 and the suffixes L, U, UL, LL, ULL

Values for manipulating statements
val mkStmt : stmtkind -> stmt
Construct a statement, given its kind. Initialize the sid field to -1, and labels, succs and preds to the empty list
val mkBlock : stmt list -> block
Construct a block with no attributes, given a list of statements
val mkStmtOneInstr : instr -> stmt
Construct a statement consisting of just one instruction
val compactStmts : stmt list -> stmt list
Try to compress statements so as to get maximal basic blocks. use this instead of List.@ because you get fewer basic blocks
val mkEmptyStmt : unit -> stmt
Returns an empty statement (of kind Instr)
val dummyInstr : instr
A instr to serve as a placeholder
val dummyStmt : stmt
A statement consisting of just dummyInstr
val mkWhile : guard:exp -> body:stmt list -> stmt list
Make a while loop. Can contain Break or Continue
val mkForIncr : iter:varinfo ->
       first:exp ->
       stopat:exp -> incr:exp -> body:stmt list -> stmt list
Make a for loop for(i=start; i<past; i += incr) { ... }. The body can contain Break but not Continue. Can be used with i a pointer or an integer. Start and done must have the same type but incr must be an integer
val mkFor : start:stmt list ->
       guard:exp -> next:stmt list -> body:stmt list -> stmt list
Make a for loop for(start; guard; next) { ... }. The body can contain Break but not Continue !!!

Values for manipulating attributes

type attributeClass =
| AttrName of bool (*Attribute of a name. If argument is true and we are on MSVC then the attribute is printed using __declspec as part of the storage specifier*)
| AttrFunType of bool (*Attribute of a function type. If argument is true and we are on MSVC then the attribute is printed just before the function name*)
| AttrType (*Attribute of a type*)
Various classes of attributes
val attributeHash : (string, attributeClass) Hashtbl.t
This table contains the mapping of predefined attributes to classes. Extend this table with more attributes as you need. This table is used to determine how to associate attributes with names or types
val partitionAttributes : default:attributeClass ->
       attributes ->
       attribute list * attribute list * attribute list
Partition the attributes into classes:name attributes, function type, and type attributes
val addAttribute : attribute -> attributes -> attributes
Add an attribute. Maintains the attributes in sorted order of the second argument
val addAttributes : attribute list -> attributes -> attributes
Add a list of attributes. Maintains the attributes in sorted order. The second argument must be sorted, but not necessarily the first
val dropAttribute : string -> attributes -> attributes
Remove all attributes with the given name. Maintains the attributes in sorted order.
val dropAttributes : string list -> attributes -> attributes
Remove all attributes with names appearing in the string list. Maintains the attributes in sorted order
val filterAttributes : string -> attributes -> attributes
Retains attributes with the given name
val hasAttribute : string -> attributes -> bool
True if the named attribute appears in the attribute list. The list of attributes must be sorted.
val typeAttrs : typ -> attribute list
Returns all the attributes contained in a type. This requires a traversal of the type structure, in case of composite, enumeration and named types
val setTypeAttrs : typ -> attributes -> typ
val typeAddAttributes : attribute list -> typ -> typ
Add some attributes to a type
val typeRemoveAttributes : string list -> typ -> typ
Remove all attributes with the given names from a type. Note that this does not remove attributes from typedef and tag definitions, just from their uses
val expToAttrParam : exp -> attrparam
Convert an expression into an attrparam, if possible. Otherwise raise NotAnAttrParam with the offending subexpression
exception NotAnAttrParam of exp

The visitor

type 'a visitAction =
| SkipChildren (*Do not visit the children. Return the node as it is.*)
| DoChildren (*Continue with the children of this node. Rebuild the node on return if any of the children changes (use == test)*)
| ChangeTo of 'a (*Replace the expression with the given one*)
| ChangeDoChildrenPost of 'a * ('a -> 'a) (*First consider that the entire exp is replaced by the first parameter. Then continue with the children. On return rebuild the node if any of the children has changed and then apply the function on the node*)
Different visiting actions. 'a will be instantiated with exp, instr, etc.
class type cilVisitor = object .. end
A visitor interface for traversing CIL trees. 
class nopCilVisitor : cilVisitor
Default Visitor. 
val visitCilFile : cilVisitor -> file -> unit
Visit a file. This will will re-cons all globals TWICE (so that it is tail-recursive). Use Cil.visitCilFileSameGlobals if your visitor will not change the list of globals.
val visitCilFileSameGlobals : cilVisitor -> file -> unit
A visitor for the whole file that does not change the globals (but maybe changes things inside the globals). Use this function instead of Cil.visitCilFile whenever appropriate because it is more efficient for long files.
val visitCilGlobal : cilVisitor -> global -> global list
Visit a global
val visitCilFunction : cilVisitor -> fundec -> fundec
Visit a function definition
val visitCilExpr : cilVisitor -> exp -> exp
val visitCilLval : cilVisitor -> lval -> lval
Visit an lvalue
val visitCilOffset : cilVisitor -> offset -> offset
Visit an lvalue or recursive offset
val visitCilInitOffset : cilVisitor -> offset -> offset
Visit an initializer offset
val visitCilInstr : cilVisitor -> instr -> instr list
Visit an instruction
val visitCilStmt : cilVisitor -> stmt -> stmt
Visit a statement
val visitCilBlock : cilVisitor -> block -> block
Visit a block
val visitCilType : cilVisitor -> typ -> typ
Visit a type
val visitCilVarDecl : cilVisitor -> varinfo -> varinfo
Visit a variable declaration
val visitCilInit : cilVisitor -> varinfo -> offset -> init -> init
Visit an initializer, pass also the global to which this belongs and the offset.
val visitCilAttributes : cilVisitor -> attribute list -> attribute list
Visit a list of attributes

Utility functions
val msvcMode : bool ref
Whether the pretty printer should print output for the MS VC compiler. Default is GCC. After you set this function you should call Cil.initCIL.
val useLogicalOperators : bool ref
Whether to use the logical operands LAnd and LOr. By default, do not use them because they are unlike other expressions and do not evaluate both of their operands
val constFoldVisitor : bool -> cilVisitor
A visitor that does constant folding. Pass as argument whether you want machine specific simplifications to be done, or not.

type lineDirectiveStyle =
| LineComment (*Before every element, print the line number in comments. This is ignored by processing tools (thus errors are reproted in the CIL output), but useful for visual inspection*)
| LineCommentSparse (*Like LineComment but only print a line directive for a new source line*)
| LinePreprocessorInput (*Use # nnn directives (in gcc mode)*)
| LinePreprocessorOutput (*Use #line directives*)
Styles of printing line directives
val lineDirectiveStyle : lineDirectiveStyle option ref
How to print line directives
val print_CIL_Input : bool ref
Whether we print something that will only be used as input to our own parser. In that case we are a bit more liberal in what we print
val printCilAsIs : bool ref
Whether to print the CIL as they are, without trying to be smart and print nicer code. Normally this is false, in which case the pretty printer will turn the while(1) loops of CIL into nicer loops, will not print empty "else" blocks, etc. These is one case howewer in which if you turn this on you will get code that does not compile: if you use varargs the __builtin_va_arg function will be printed in its internal form.
val lineLength : int ref
The length used when wrapping output lines. Setting this variable to a large integer will prevent wrapping and make #line directives more accurate.
val forgcc : string -> string
Return the string 's' if we're printing output for gcc, suppres it if we're printing for CIL to parse back in. the purpose is to hide things from gcc that it complains about, but still be able to do lossless transformations when CIL is the consumer

Debugging support
val currentLoc : location ref
A reference to the current location. If you are careful to set this to the current location then you can use some built-in logging functions that will print the location.
val currentGlobal : global ref
A reference to the current global being visited

CIL has a fairly easy to use mechanism for printing error messages. This mechanism is built on top of the pretty-printer mechanism (see Pretty.doc) and the error-message modules (see Errormsg.error).

Here is a typical example for printing a log message: 

ignore (Errormsg.log "Expression %a is not positive (at %s:%i)\n"
                        d_exp e loc.file loc.line)

and here is an example of how you print a fatal error message that stop the execution: 

Errormsg.s (Errormsg.bug "Why am I here?")

Notice that you can use C format strings with some extension. The most useful extension is "%a" that means to consumer the next two argument from the argument list and to apply the first to unit and then to the second and to print the resulting Pretty.doc. For each major type in CIL there is a corresponding function that pretty-prints an element of that type:

val d_loc : unit -> location -> Pretty.doc
Pretty-print a location
val d_thisloc : unit -> Pretty.doc
Pretty-print the Cil.currentLoc
val d_ikind : unit -> ikind -> Pretty.doc
Pretty-print an integer of a given kind
val d_fkind : unit -> fkind -> Pretty.doc
Pretty-print a floating-point kind
val d_storage : unit -> storage -> Pretty.doc
Pretty-print storage-class information
val d_const : unit -> constant -> Pretty.doc
Pretty-print a constant
val derefStarLevel : int
val indexLevel : int
val arrowLevel : int
val addrOfLevel : int
val additiveLevel : int
val comparativeLevel : int
val bitwiseLevel : int
val getParenthLevel : exp -> int
Parentheses level. An expression "a op b" is printed parenthesized if its parentheses level is >= that that of its context. Identifiers have the lowest level and weakly binding operators (e.g. |) have the largest level. The correctness criterion is that a smaller level MUST correspond to a stronger precedence!
class type cilPrinter = object .. end
A printer interface for CIL trees. 
class defaultCilPrinterClass : cilPrinter
val defaultCilPrinter : cilPrinter
class plainCilPrinterClass : cilPrinter
These are pretty-printers that will show you more details on the internal CIL representation, without trying hard to make it look like C 
val plainCilPrinter : cilPrinter
class type descriptiveCilPrinter = object .. end
class descriptiveCilPrinterClass : descriptiveCilPrinter
Like defaultCilPrinterClass, but instead of temporary variable names it prints the description that was provided when the temp was created. 
val descriptiveCilPrinter : descriptiveCilPrinter
val printerForMaincil : cilPrinter ref
zra: This is the pretty printer that Maincil will use. by default it is set to defaultCilPrinter
val printType : cilPrinter -> unit -> typ -> Pretty.doc
Print a type given a pretty printer
val printExp : cilPrinter -> unit -> exp -> Pretty.doc
Print an expression given a pretty printer
val printLval : cilPrinter -> unit -> lval -> Pretty.doc
Print an lvalue given a pretty printer
val printGlobal : cilPrinter -> unit -> global -> Pretty.doc
Print a global given a pretty printer
val printAttr : cilPrinter -> unit -> attribute -> Pretty.doc
Print an attribute given a pretty printer
val printAttrs : cilPrinter -> unit -> attributes -> Pretty.doc
Print a set of attributes given a pretty printer
val printInstr : cilPrinter -> unit -> instr -> Pretty.doc
Print an instruction given a pretty printer
val printStmt : cilPrinter -> unit -> stmt -> Pretty.doc
Print a statement given a pretty printer. This can take very long (or even overflow the stack) for huge statements. Use Cil.dumpStmt instead.
val printBlock : cilPrinter -> unit -> block -> Pretty.doc
Print a block given a pretty printer. This can take very long (or even overflow the stack) for huge block. Use Cil.dumpBlock instead.
val dumpStmt : cilPrinter -> out_channel -> int -> stmt -> unit
Dump a statement to a file using a given indentation. Use this instead of Cil.printStmt whenever possible.
val dumpBlock : cilPrinter -> out_channel -> int -> block -> unit
Dump a block to a file using a given indentation. Use this instead of Cil.printBlock whenever possible.
val printInit : cilPrinter -> unit -> init -> Pretty.doc
Print an initializer given a pretty printer. This can take very long (or even overflow the stack) for huge initializers. Use Cil.dumpInit instead.
val dumpInit : cilPrinter -> out_channel -> int -> init -> unit
Dump an initializer to a file using a given indentation. Use this instead of Cil.printInit whenever possible.
val d_type : unit -> typ -> Pretty.doc
Pretty-print a type using Cil.defaultCilPrinter
val d_exp : unit -> exp -> Pretty.doc
Pretty-print an expression using Cil.defaultCilPrinter
val d_lval : unit -> lval -> Pretty.doc
Pretty-print an lvalue using Cil.defaultCilPrinter
val d_offset : Pretty.doc -> unit -> offset -> Pretty.doc
Pretty-print an offset using Cil.defaultCilPrinter, given the pretty printing for the base.
val d_init : unit -> init -> Pretty.doc
Pretty-print an initializer using Cil.defaultCilPrinter. This can be extremely slow (or even overflow the stack) for huge initializers. Use Cil.dumpInit instead.
val d_binop : unit -> binop -> Pretty.doc
Pretty-print a binary operator
val d_unop : unit -> unop -> Pretty.doc
Pretty-print a unary operator
val d_attr : unit -> attribute -> Pretty.doc
Pretty-print an attribute using Cil.defaultCilPrinter
val d_attrparam : unit -> attrparam -> Pretty.doc
Pretty-print an argument of an attribute using Cil.defaultCilPrinter
val d_attrlist : unit -> attributes -> Pretty.doc
Pretty-print a list of attributes using Cil.defaultCilPrinter
val d_instr : unit -> instr -> Pretty.doc
Pretty-print an instruction using Cil.defaultCilPrinter
val d_label : unit -> label -> Pretty.doc
Pretty-print a label using Cil.defaultCilPrinter
val d_stmt : unit -> stmt -> Pretty.doc
Pretty-print a statement using Cil.defaultCilPrinter. This can be extremely slow (or even overflow the stack) for huge statements. Use Cil.dumpStmt instead.
val d_block : unit -> block -> Pretty.doc
Pretty-print a block using Cil.defaultCilPrinter. This can be extremely slow (or even overflow the stack) for huge blocks. Use Cil.dumpBlock instead.
val d_global : unit -> global -> Pretty.doc
Pretty-print the internal representation of a global using Cil.defaultCilPrinter. This can be extremely slow (or even overflow the stack) for huge globals (such as arrays with lots of initializers). Use Cil.dumpGlobal instead.
val dn_exp : unit -> exp -> Pretty.doc
Versions of the above pretty printers, that don't print #line directives
val dn_lval : unit -> lval -> Pretty.doc
val dn_init : unit -> init -> Pretty.doc
val dn_type : unit -> typ -> Pretty.doc
val dn_global : unit -> global -> Pretty.doc
val dn_attrlist : unit -> attributes -> Pretty.doc
val dn_attr : unit -> attribute -> Pretty.doc
val dn_attrparam : unit -> attrparam -> Pretty.doc
val dn_stmt : unit -> stmt -> Pretty.doc
val dn_instr : unit -> instr -> Pretty.doc
val d_shortglobal : unit -> global -> Pretty.doc
Pretty-print a short description of the global. This is useful for error messages
val dumpGlobal : cilPrinter -> out_channel -> global -> unit
Pretty-print a global. Here you give the channel where the printout should be sent.
val dumpFile : cilPrinter -> out_channel -> string -> file -> unit
Pretty-print an entire file. Here you give the channel where the printout should be sent.

the following error message producing functions also print a location in the code. use Errormsg.bug and Errormsg.unimp if you do not want that
val bug : ('a, unit, Pretty.doc) format -> 'a
Like Errormsg.bug except that Cil.currentLoc is also printed
val unimp : ('a, unit, Pretty.doc) format -> 'a
Like Errormsg.unimp except that Cil.currentLocis also printed
val error : ('a, unit, Pretty.doc) format -> 'a
Like Errormsg.error except that Cil.currentLoc is also printed
val errorLoc : location -> ('a, unit, Pretty.doc) format -> 'a
Like Cil.error except that it explicitly takes a location argument, instead of using the Cil.currentLoc
val warn : ('a, unit, Pretty.doc) format -> 'a
Like Errormsg.warn except that Cil.currentLoc is also printed
val warnOpt : ('a, unit, Pretty.doc) format -> 'a
Like Errormsg.warnOpt except that Cil.currentLoc is also printed. This warning is printed only of Errormsg.warnFlag is set.
val warnContext : ('a, unit, Pretty.doc) format -> 'a
Like Errormsg.warn except that Cil.currentLoc and context is also printed
val warnContextOpt : ('a, unit, Pretty.doc) format -> 'a
Like Errormsg.warn except that Cil.currentLoc and context is also printed. This warning is printed only of Errormsg.warnFlag is set.
val warnLoc : location -> ('a, unit, Pretty.doc) format -> 'a
Like Cil.warn except that it explicitly takes a location argument, instead of using the Cil.currentLoc

Sometimes you do not want to see the syntactic sugar that the above pretty-printing functions add. In that case you can use the following pretty-printing functions. But note that the output of these functions is not valid C
val d_plainexp : unit -> exp -> Pretty.doc
Pretty-print the internal representation of an expression
val d_plaininit : unit -> init -> Pretty.doc
Pretty-print the internal representation of an integer
val d_plainlval : unit -> lval -> Pretty.doc
Pretty-print the internal representation of an lvalue

Pretty-print the internal representation of an lvalue offset val d_plainoffset: unit -> offset -> Pretty.doc
val d_plaintype : unit -> typ -> Pretty.doc
Pretty-print the internal representation of a type
val dd_exp : unit -> exp -> Pretty.doc
Pretty-print an expression while printing descriptions rather than names of temporaries.

ALPHA conversion has been moved to the Alpha module.
val uniqueVarNames : file -> unit
Assign unique names to local variables. This might be necessary after you transformed the code and added or renamed some new variables. Names are not used by CIL internally, but once you print the file out the compiler downstream might be confused. You might have added a new global that happens to have the same name as a local in some function. Rename the local to ensure that there would never be confusioin. Or, viceversa, you might have added a local with a name that conflicts with a global

Optimization Passes
val peepHole2 : (instr * instr -> instr list option) -> stmt list -> unit
A peephole optimizer that processes two adjacent statements and possibly replaces them both. If some replacement happens, then the new statements are themselves subject to optimization
val peepHole1 : (instr -> instr list option) -> stmt list -> unit
Similar to peepHole2 except that the optimization window consists of one statement, not two

Machine dependency
exception SizeOfError of string * typ
Raised when one of the bitsSizeOf functions cannot compute the size of a type. This can happen because the type contains array-length expressions that we don't know how to compute or because it is a type whose size is not defined (e.g. TFun or an undefined compinfo). The string is an explanation of the error
val bitsSizeOf : typ -> int
The size of a type, in bits. Trailing padding is added for structs and arrays. Raises Cil.SizeOfError when it cannot compute the size. This function is architecture dependent, so you should only call this after you call Cil.initCIL. Remember that on GCC sizeof(void) is 1!
val truncateInteger64 : ikind -> int64 -> int64 * bool
val sizeOf : typ -> exp
The size of a type, in bytes. Returns a constant expression or a "sizeof" expression if it cannot compute the size. This function is architecture dependent, so you should only call this after you call Cil.initCIL.
val alignOf_int : typ -> int
The minimum alignment (in bytes) for a type. This function is architecture dependent, so you should only call this after you call Cil.initCIL.
val bitsOffset : typ -> offset -> int * int
Give a type of a base and an offset, returns the number of bits from the base address and the width (also expressed in bits) for the subobject denoted by the offset. Raises Cil.SizeOfError when it cannot compute the size. This function is architecture dependent, so you should only call this after you call Cil.initCIL.
val char_is_unsigned : bool ref
Whether "char" is unsigned. Set after you call Cil.initCIL
val little_endian : bool ref
Whether the machine is little endian. Set after you call Cil.initCIL
val underscore_name : bool ref
Whether the compiler generates assembly labels by prepending "_" to the identifier. That is, will function foo() have the label "foo", or "_foo"? Set after you call Cil.initCIL
val locUnknown : location
Represents a location that cannot be determined
val get_instrLoc : instr -> location
Return the location of an instruction
val get_globalLoc : global -> location
Return the location of a global, or locUnknown
val get_stmtLoc : stmtkind -> location
Return the location of a statement, or locUnknown
val dExp : Pretty.doc -> exp
Generate an Cil.exp to be used in case of errors.
val dInstr : Pretty.doc -> location -> instr
Generate an Cil.instr to be used in case of errors.
val dGlobal : Pretty.doc -> location -> global
Generate a Cil.global to be used in case of errors.
val mapNoCopy : ('a -> 'a) -> 'a list -> 'a list
Like map but try not to make a copy of the list
val mapNoCopyList : ('a -> 'a list) -> 'a list -> 'a list
Like map but each call can return a list. Try not to make a copy of the list
val startsWith : string -> string -> bool
sm: return true if the first is a prefix of the second string

An Interpreter for constructing CIL constructs

type formatArg =
| Fe of exp
| Feo of exp option (*For array lengths*)
| Fu of unop
| Fb of binop
| Fk of ikind
| FE of exp list (*For arguments in a function call*)
| Ff of (string * typ * attributes) (*For a formal argument*)
| FF of (string * typ * attributes) list (*For formal argument lists*)
| Fva of bool (*For the ellipsis in a function type*)
| Fv of varinfo
| Fl of lval
| Flo of lval option
| Fo of offset
| Fc of compinfo
| Fi of instr
| FI of instr list
| Ft of typ
| Fd of int
| Fg of string
| Fs of stmt
| FS of stmt list
| FA of attributes
| Fp of attrparam
| FP of attrparam list
| FX of string
The type of argument for the interpreter
val d_formatarg : unit -> formatArg -> Pretty.doc
Pretty-prints a format arg
val warnTruncate : bool ref
Emit warnings when truncating integer constants (default true)