[llvm] r175847 - Code cleanup: pass Offset by pointer to parseInstruction to more explicitly
Eli Bendersky
eliben at google.com
Thu Feb 21 16:50:49 PST 2013
Author: eliben
Date: Thu Feb 21 18:50:48 2013
New Revision: 175847
URL: http://llvm.org/viewvc/llvm-project?rev=175847&view=rev
Log:
Code cleanup: pass Offset by pointer to parseInstruction to more explicitly
convey that it's a INOUT argument.
Also, if parsing of entry instructions fails, don't push the entry.
Modified:
llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp
Modified: llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp?rev=175847&r1=175846&r2=175847&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp (original)
+++ llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp Thu Feb 21 18:50:48 2013
@@ -36,11 +36,10 @@ public:
virtual uint64_t getOffset() const { return Offset; }
/// \brief Parse and store a sequence of CFI instructions from our data
- /// stream, starting at Offset and ending at EndOffset. If everything
- /// goes well, Offset should be equal to EndOffset when this method
+ /// stream, starting at *Offset and ending at EndOffset. If everything
+ /// goes well, *Offset should be equal to EndOffset when this method
/// returns. Otherwise, an error occurred.
- /// TODO: Improve error reporting...
- virtual void parseInstructions(uint32_t &Offset, uint32_t EndOffset);
+ virtual void parseInstructions(uint32_t *Offset, uint32_t EndOffset);
/// \brief Dump the entry header to the given output stream.
virtual void dumpHeader(raw_ostream &OS) const = 0;
@@ -99,9 +98,9 @@ const uint8_t DWARF_CFI_PRIMARY_OPCODE_M
const uint8_t DWARF_CFI_PRIMARY_OPERAND_MASK = 0x3f;
-void FrameEntry::parseInstructions(uint32_t &Offset, uint32_t EndOffset) {
- while (Offset < EndOffset) {
- uint8_t Opcode = Data.getU8(&Offset);
+void FrameEntry::parseInstructions(uint32_t *Offset, uint32_t EndOffset) {
+ while (*Offset < EndOffset) {
+ uint8_t Opcode = Data.getU8(Offset);
// Some instructions have a primary opcode encoded in the top bits.
uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK;
@@ -116,7 +115,7 @@ void FrameEntry::parseInstructions(uint3
addInstruction(Primary, Op1);
break;
case DW_CFA_offset:
- addInstruction(Primary, Op1, Data.getULEB128(&Offset));
+ addInstruction(Primary, Op1, Data.getULEB128(Offset));
break;
}
} else {
@@ -131,19 +130,19 @@ void FrameEntry::parseInstructions(uint3
break;
case DW_CFA_set_loc:
// Operands: Address
- addInstruction(Opcode, Data.getAddress(&Offset));
+ addInstruction(Opcode, Data.getAddress(Offset));
break;
case DW_CFA_advance_loc1:
// Operands: 1-byte delta
- addInstruction(Opcode, Data.getU8(&Offset));
+ addInstruction(Opcode, Data.getU8(Offset));
break;
case DW_CFA_advance_loc2:
// Operands: 2-byte delta
- addInstruction(Opcode, Data.getU16(&Offset));
+ addInstruction(Opcode, Data.getU16(Offset));
break;
case DW_CFA_advance_loc4:
// Operands: 4-byte delta
- addInstruction(Opcode, Data.getU32(&Offset));
+ addInstruction(Opcode, Data.getU32(Offset));
break;
case DW_CFA_restore_extended:
case DW_CFA_undefined:
@@ -151,26 +150,26 @@ void FrameEntry::parseInstructions(uint3
case DW_CFA_def_cfa_register:
case DW_CFA_def_cfa_offset:
// Operands: ULEB128
- addInstruction(Opcode, Data.getULEB128(&Offset));
+ addInstruction(Opcode, Data.getULEB128(Offset));
break;
case DW_CFA_def_cfa_offset_sf:
// Operands: SLEB128
- addInstruction(Opcode, Data.getSLEB128(&Offset));
+ addInstruction(Opcode, Data.getSLEB128(Offset));
break;
case DW_CFA_offset_extended:
case DW_CFA_register:
case DW_CFA_def_cfa:
case DW_CFA_val_offset:
// Operands: ULEB128, ULEB128
- addInstruction(Opcode, Data.getULEB128(&Offset),
- Data.getULEB128(&Offset));
+ addInstruction(Opcode, Data.getULEB128(Offset),
+ Data.getULEB128(Offset));
break;
case DW_CFA_offset_extended_sf:
case DW_CFA_def_cfa_sf:
case DW_CFA_val_offset_sf:
// Operands: ULEB128, SLEB128
- addInstruction(Opcode, Data.getULEB128(&Offset),
- Data.getSLEB128(&Offset));
+ addInstruction(Opcode, Data.getULEB128(Offset),
+ Data.getSLEB128(Offset));
break;
case DW_CFA_def_cfa_expression:
case DW_CFA_expression:
@@ -337,37 +336,42 @@ void DWARFDebugFrame::parse(DataExtracto
Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4);
bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID);
+ FrameEntry *Entry = 0;
if (IsCIE) {
// Note: this is specifically DWARFv3 CIE header structure. It was
- // changed in DWARFv4.
+ // changed in DWARFv4. We currently don't support reading DWARFv4
+ // here because LLVM itself does not emit it (and LLDB doesn't
+ // support it either).
uint8_t Version = Data.getU8(&Offset);
const char *Augmentation = Data.getCStr(&Offset);
uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset);
int64_t DataAlignmentFactor = Data.getSLEB128(&Offset);
uint64_t ReturnAddressRegister = Data.getULEB128(&Offset);
- CIE *NewCIE = new CIE(Data, StartOffset, Length, Version,
- StringRef(Augmentation), CodeAlignmentFactor,
- DataAlignmentFactor, ReturnAddressRegister);
- Entries.push_back(NewCIE);
+ Entry = new CIE(Data, StartOffset, Length, Version,
+ StringRef(Augmentation), CodeAlignmentFactor,
+ DataAlignmentFactor, ReturnAddressRegister);
} else {
// FDE
uint64_t CIEPointer = Id;
uint64_t InitialLocation = Data.getAddress(&Offset);
uint64_t AddressRange = Data.getAddress(&Offset);
- FDE *NewFDE = new FDE(Data, StartOffset, Length, CIEPointer,
- InitialLocation, AddressRange);
- Entries.push_back(NewFDE);
+ Entry = new FDE(Data, StartOffset, Length, CIEPointer,
+ InitialLocation, AddressRange);
}
- Entries.back()->parseInstructions(Offset, EndStructureOffset);
+ assert(Entry && "Expected Entry to be populated with CIE or FDE");
+ Entry->parseInstructions(&Offset, EndStructureOffset);
- if (Offset != EndStructureOffset) {
+ if (Offset == EndStructureOffset) {
+ // Entry instrucitons parsed successfully.
+ Entries.push_back(Entry);
+ } else {
std::string Str;
raw_string_ostream OS(Str);
OS << format("Parsing entry instructions at %lx failed",
- Entries.back()->getOffset());
+ Entry->getOffset());
report_fatal_error(Str);
}
}
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