Adding a C API to the disassembler for use by such tools as Darwin's otool(1).

This is a work in progress as the interface for producing symbolic operands is
not done.  But a hacked prototype using information from the object file's
relocation entiries and replacing immediate operands with MCExpr's has been
shown to work with no changes to the instrucion printer.  These APIs will be
moved into a dynamic library at some point.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128308 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 106 insertions, 0 deletions

diff --git a/include/llvm-c/Disassembler.h b/include/llvm-c/Disassembler.h
new file mode 100644
index 0000000000..742063025f
--- /dev/null
+++ b/include/llvm-c/Disassembler.h
@@ -0,0 +1,106 @@
+/*===-- llvm-c/Disassembler.h - Disassembler Public C Interface ---*- C -*-===*\
+|*                                                                            *|
+|*                     The LLVM Compiler Infrastructure                       *|
+|*                                                                            *|
+|* This file is distributed under the University of Illinois Open Source      *|
+|* License. See LICENSE.TXT for details.                                      *|
+|*                                                                            *|
+|*===----------------------------------------------------------------------===*|
+|*                                                                            *|
+|* This header provides public interface to a disassembler library.           *|
+|* LLVM provides an implementation of this interface.                         *|
+|*                                                                            *|
+\*===----------------------------------------------------------------------===*/
+
+#ifndef LLVM_C_DISASSEMBLER_H
+#define LLVM_C_DISASSEMBLER_H  1
+
+#include <stdint.h>
+#include <stddef.h>
+
+/**
+ * An opaque reference to a disassembler context.
+ */
+typedef void *LLVMDisasmContextRef;
+
+/**
+ * The type for the operand information call back function.  This is called to
+ * get the symbolic information for an operand of an instruction.  Typically
+ * this is from the relocation information, symbol table, etc.  That block of
+ * information is saved when the disassembler context is created and passed to
+ * the call back in the DisInfo parameter.  The instruction containing operand
+ * is at the PC parameter.  For some instruction sets, there can be more than
+ * one operand with symbolic information.  To determine the symbolic operand
+ * infomation for each operand, the bytes for the specific operand in the
+ * instruction are specified by the Offset parameter and its byte widith is the
+ * size parameter.  For instructions sets with fixed widths and one symbolic
+ * operand per instruction, the Offset parameter will be zero and Size parameter
+ * will be the instruction width.  The information is returned in TagBuf and is 
+ * Triple specific with its specific information defined by the value of
+ * TagType for that Triple.  If symbolic information is returned the function
+ * returns 1 else it returns 0.
+ */
+typedef int (*LLVMOpInfoCallback)(void *DisInfo,
+                                  uint64_t PC,
+                                  uint64_t Offset,
+                                  uint64_t Size,
+                                  int TagType,
+                                  void *TagBuf);
+
+/**
+ * The type for the symbol lookup function.  This may be called by the
+ * disassembler for such things like adding a comment for a PC plus a constant
+ * offset load instruction to use a symbol name instead of a load address value.
+ * It is passed the block information is saved when the disassembler context is
+ * created and a value of a symbol to look up.  If no symbol is found NULL is
+ * to be returned.
+ */
+typedef const char *(*LLVMSymbolLookupCallback)(void *DisInfo,
+                                                uint64_t SymbolValue);
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* !defined(__cplusplus) */
+
+/**
+ * Create a disassembler for the TripleName.  Symbolic disassembly is supported
+ * by passing a block of information in the DisInfo parameter and specifing the
+ * TagType and call back functions as described above.  These can all be passed
+ * as NULL.  If successfull this returns a disassembler context if not it
+ * returns NULL.
+ */
+extern LLVMDisasmContextRef
+LLVMCreateDisasm(const char *TripleName,
+                 void *DisInfo,
+                 int TagType,
+                 LLVMOpInfoCallback GetOpInfo,
+                 LLVMSymbolLookupCallback SymbolLookUp);
+
+/**
+ * Dispose of a disassembler context.
+ */
+extern void
+LLVMDisasmDispose(LLVMDisasmContextRef DC);
+
+/**
+ * Disassmble a single instruction using the disassembler context specified in
+ * the parameter DC.  The bytes of the instuction are specified in the parameter
+ * Bytes, and contains at least BytesSize number of bytes.  The instruction is
+ * at the address specified by the PC parameter.  If a valid instruction can be
+ * disassembled its string is returned indirectly in OutString which whos size
+ * is specified in the parameter OutStringSize.  This function returns the
+ * number of bytes in the instruction or zero if there was no valid instruction.
+ */
+extern size_t
+LLVMDisasmInstruction(LLVMDisasmContextRef DC,
+                      uint8_t *Bytes,
+                      uint64_t BytesSize,
+                      uint64_t PC,
+                      char *OutString,
+                      size_t OutStringSize);
+
+#ifdef __cplusplus
+}
+#endif /* !defined(__cplusplus) */
+
+#endif /* !defined(LLVM_C_DISASSEMBLER_H) */