AsmPrinterDwarf.cpp revision 4bfddc846a0c7c332277099062c1a7b623d2bdec 
1//===-- AsmPrinterDwarf.cpp - AsmPrinter Dwarf Support --------------------===//
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 file implements the Dwarf emissions parts of AsmPrinter.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "asm-printer"
15#include "llvm/CodeGen/AsmPrinter.h"
16#include "llvm/MC/MCAsmInfo.h"
17#include "llvm/MC/MCStreamer.h"
18#include "llvm/ADT/Twine.h"
19#include "llvm/Support/Dwarf.h"
20using namespace llvm;
21
22/// EmitSLEB128 - emit the specified signed leb128 value.
23void AsmPrinter::EmitSLEB128(int Value, const char *Desc) const {
24  if (isVerbose() && Desc)
25    OutStreamer.AddComment(Desc);
26
27  if (MAI->hasLEB128()) {
28    // FIXME: MCize.
29    OutStreamer.EmitRawText("\t.sleb128\t" + Twine(Value));
30    return;
31  }
32
33  // If we don't have .sleb128, emit as .bytes.
34  int Sign = Value >> (8 * sizeof(Value) - 1);
35  bool IsMore;
36
37  do {
38    unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
39    Value >>= 7;
40    IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
41    if (IsMore) Byte |= 0x80;
42    OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
43  } while (IsMore);
44}
45
46/// EmitULEB128 - emit the specified signed leb128 value.
47void AsmPrinter::EmitULEB128(unsigned Value, const char *Desc,
48                             unsigned PadTo) const {
49  if (isVerbose() && Desc)
50    OutStreamer.AddComment(Desc);
51
52  if (MAI->hasLEB128() && PadTo == 0) {
53    // FIXME: MCize.
54    OutStreamer.EmitRawText("\t.uleb128\t" + Twine(Value));
55    return;
56  }
57
58  // If we don't have .uleb128 or we want to emit padding, emit as .bytes.
59  do {
60    unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
61    Value >>= 7;
62    if (Value || PadTo != 0) Byte |= 0x80;
63    OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
64  } while (Value);
65
66  if (PadTo) {
67    if (PadTo > 1)
68      OutStreamer.EmitFill(PadTo - 1, 0x80/*fillval*/, 0/*addrspace*/);
69    OutStreamer.EmitFill(1, 0/*fillval*/, 0/*addrspace*/);
70  }
71}
72
73/// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value.
74void AsmPrinter::EmitCFAByte(unsigned Val) const {
75  if (isVerbose()) {
76    if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset+64)
77      OutStreamer.AddComment("DW_CFA_offset + Reg (" +
78                             Twine(Val-dwarf::DW_CFA_offset) + ")");
79    else
80      OutStreamer.AddComment(dwarf::CallFrameString(Val));
81  }
82  OutStreamer.EmitIntValue(Val, 1, 0/*addrspace*/);
83}
84
85