include/llvm-c/Disassembler.h

   1 /*===-- llvm-c/Disassembler.h - Disassembler Public C Interface ---*- C -*-===*\
   2 |*                                                                            *|
   3 |*                     The LLVM Compiler Infrastructure                       *|
   4 |*                                                                            *|
   5 |* This file is distributed under the University of Illinois Open Source      *|
   6 |* License. See LICENSE.TXT for details.                                      *|
   7 |*                                                                            *|
   8 |*===----------------------------------------------------------------------===*|
   9 |*                                                                            *|
  10 |* This header provides a public interface to a disassembler library.         *|
  11 |* LLVM provides an implementation of this interface.                         *|
  12 |*                                                                            *|
  13 \*===----------------------------------------------------------------------===*/
  14
  15 #ifndef LLVM_C_DISASSEMBLER_H
  16 #define LLVM_C_DISASSEMBLER_H
  17
  18 #include "llvm/Support/DataTypes.h"
  19 #include <stddef.h>
  20
  21 /**
  22  * An opaque reference to a disassembler context.
  23  */
  24 typedef void *LLVMDisasmContextRef;
  25
  26 /**
  27  * The type for the operand information call back function.  This is called to
  28  * get the symbolic information for an operand of an instruction.  Typically
  29  * this is from the relocation information, symbol table, etc.  That block of
  30  * information is saved when the disassembler context is created and passed to
  31  * the call back in the DisInfo parameter.  The instruction containing operand
  32  * is at the PC parameter.  For some instruction sets, there can be more than
  33  * one operand with symbolic information.  To determine the symbolic operand
  34  * information for each operand, the bytes for the specific operand in the
  35  * instruction are specified by the Offset parameter and its byte widith is the
  36  * size parameter.  For instructions sets with fixed widths and one symbolic
  37  * operand per instruction, the Offset parameter will be zero and Size parameter
  38  * will be the instruction width.  The information is returned in TagBuf and is
  39  * Triple specific with its specific information defined by the value of
  40  * TagType for that Triple.  If symbolic information is returned the function
  41  * returns 1, otherwise it returns 0.
  42  */
  43 typedef int (*LLVMOpInfoCallback)(void *DisInfo, uint64_t PC,
  44                                   uint64_t Offset, uint64_t Size,
  45                                   int TagType, void *TagBuf);
  46
  47 /**
  48  * The initial support in LLVM MC for the most general form of a relocatable
  49  * expression is "AddSymbol - SubtractSymbol + Offset".  For some Darwin targets
  50  * this full form is encoded in the relocation information so that AddSymbol and
  51  * SubtractSymbol can be link edited independent of each other.  Many other
  52  * platforms only allow a relocatable expression of the form AddSymbol + Offset
  53  * to be encoded.
  54  *
  55  * The LLVMOpInfoCallback() for the TagType value of 1 uses the struct
  56  * LLVMOpInfo1.  The value of the relocatable expression for the operand,
  57  * including any PC adjustment, is passed in to the call back in the Value
  58  * field.  The symbolic information about the operand is returned using all
  59  * the fields of the structure with the Offset of the relocatable expression
  60  * returned in the Value field.  It is possible that some symbols in the
  61  * relocatable expression were assembly temporary symbols, for example
  62  * "Ldata - LpicBase + constant", and only the Values of the symbols without
  63  * symbol names are present in the relocation information.  The VariantKind
  64  * type is one of the Target specific #defines below and is used to print
  65  * operands like "_foo@GOT", ":lower16:_foo", etc.
  66  */
  67 struct LLVMOpInfoSymbol1 {
  68   uint64_t Present;  /* 1 if this symbol is present */
  69   char *Name;        /* symbol name if not NULL */
  70   uint64_t Value;    /* symbol value if name is NULL */
  71 };
  72
  73 struct LLVMOpInfo1 {
  74   struct LLVMOpInfoSymbol1 AddSymbol;
  75   struct LLVMOpInfoSymbol1 SubtractSymbol;
  76   uint64_t Value;
  77   uint64_t VariantKind;
  78 };
  79
  80 /**
  81  * The operand VariantKinds for symbolic disassembly.
  82  */
  83 #define LLVMDisassembler_VariantKind_None 0 /* all targets */
  84
  85 /**
  86  * The ARM target VariantKinds.
  87  */
  88 #define LLVMDisassembler_VariantKind_ARM_HI16 1 /* :upper16: */
  89 #define LLVMDisassembler_VariantKind_ARM_LO16 2 /* :lower16: */
  90
  91 /**
  92  * The type for the symbol lookup function.  This may be called by the
  93  * disassembler for things like adding a comment for a PC plus a constant
  94  * offset load instruction to use a symbol name instead of a load address value.
  95  * It is passed the block information is saved when the disassembler context is
  96  * created and a value of a symbol to look up.  If no symbol is found NULL is
  97  * returned.
  98  */
  99 typedef const char *(*LLVMSymbolLookupCallback)(void *DisInfo,
 100                                                 uint64_t SymbolValue);
 101
 102 #ifdef __cplusplus
 103 extern "C" {
 104 #endif /* !defined(__cplusplus) */
 105
 106 /**
 107  * Create a disassembler for the TripleName.  Symbolic disassembly is supported
 108  * by passing a block of information in the DisInfo parameter and specifying the
 109  * TagType and callback functions as described above.  These can all be passed
 110  * as NULL.  If successful, this returns a disassembler context.  If not, it
 111  * returns NULL.
 112  */
 113 LLVMDisasmContextRef LLVMCreateDisasm(const char *TripleName, void *DisInfo,
 114                                       int TagType, LLVMOpInfoCallback GetOpInfo,
 115                                       LLVMSymbolLookupCallback SymbolLookUp);
 116
 117 /**
 118  * Dispose of a disassembler context.
 119  */
 120 void LLVMDisasmDispose(LLVMDisasmContextRef DC);
 121
 122 /**
 123  * Disassemble a single instruction using the disassembler context specified in
 124  * the parameter DC.  The bytes of the instruction are specified in the
 125  * parameter Bytes, and contains at least BytesSize number of bytes.  The
 126  * instruction is at the address specified by the PC parameter.  If a valid
 127  * instruction can be disassembled, its string is returned indirectly in
 128  * OutString whose size is specified in the parameter OutStringSize.  This
 129  * function returns the number of bytes in the instruction or zero if there was
 130  * no valid instruction.
 131  */
 132 size_t LLVMDisasmInstruction(LLVMDisasmContextRef DC, uint8_t *Bytes,
 133                              uint64_t BytesSize, uint64_t PC,
 134                              char *OutString, size_t OutStringSize);
 135
 136 #ifdef __cplusplus
 137 }
 138 #endif /* !defined(__cplusplus) */
 139
 140 #endif /* !defined(LLVM_C_DISASSEMBLER_H) */