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Previously, parsing capability of the .debug_frame section was added

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to lib/DebugInfo, with dumping in llvm-dwarfdump. This patch adds
initial ability to parse and dump CFA instructions contained in
entries.

To keep it manageable, the patch omits some more advanced capabilities
(accounted in TODOs):

* Parsing of instructions with BLOCK arguments (expression lists)
* Dumping of actual instruction arguments (currently only names are
dumped). This is quite tricky since the dumper has to effectively
"interpret" the instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175820 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Bendersky 2013-02-21 22:53:19 +00:00
parent 0711d46a72
commit 7bf3d6a043
3 changed files with 184 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

176
lib/DebugInfo/DWARFDebugFrame.cpp
View File

@ -10,8 +10,12 @@
#include "DWARFDebugFrame.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include <string>
#include <vector>
using namespace llvm;
using namespace dwarf;
@ -29,9 +33,21 @@ public:
}
FrameKind getKind() const { return Kind; }
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
/// returns. Otherwise, an error occurred.
/// TODO: Improve error reporting...
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;
/// \brief Dump the entry's instructions to the given output stream.
virtual void dumpInstructions(raw_ostream &OS) const;
protected:
const FrameKind Kind;
@ -44,8 +60,143 @@ protected:
/// \brief Entry length as specified in DWARF.
uint64_t Length;
/// An entry may contain CFI instructions. An instruction consists of an
/// opcode and an optional sequence of operands.
typedef std::vector<uint64_t> Operands;
struct Instruction {
Instruction(uint8_t Opcode)
: Opcode(Opcode)
{}
uint8_t Opcode;
Operands Ops;
};
std::vector<Instruction> Instructions;
/// Convenience methods to add a new instruction with the given opcode and
/// operands to the Instructions vector.
void addInstruction(uint8_t Opcode) {
Instructions.push_back(Instruction(Opcode));
}
void addInstruction(uint8_t Opcode, uint64_t Operand1) {
Instructions.push_back(Instruction(Opcode));
Instructions.back().Ops.push_back(Operand1);
}
void addInstruction(uint8_t Opcode, uint64_t Operand1, uint64_t Operand2) {
Instructions.push_back(Instruction(Opcode));
Instructions.back().Ops.push_back(Operand1);
Instructions.back().Ops.push_back(Operand2);
}
};
// See DWARF standard v3, section 7.23
const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0;
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);
// Some instructions have a primary opcode encoded in the top bits.
uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK;
if (Primary) {
// If it's a primary opcode, the first operand is encoded in the bottom
// bits of the opcode itself.
uint64_t Op1 = Opcode & DWARF_CFI_PRIMARY_OPERAND_MASK;
switch (Primary) {
default: llvm_unreachable("Impossible primary CFI opcode");
case DW_CFA_advance_loc:
case DW_CFA_restore:
addInstruction(Primary, Op1);
break;
case DW_CFA_offset:
addInstruction(Primary, Op1, Data.getULEB128(&Offset));
break;
}
} else {
// Extended opcode - its value is Opcode itself.
switch (Opcode) {
default: llvm_unreachable("Invalid extended CFI opcode");
case DW_CFA_nop:
case DW_CFA_remember_state:
case DW_CFA_restore_state:
// No operands
addInstruction(Opcode);
break;
case DW_CFA_set_loc:
// Operands: Address
addInstruction(Opcode, Data.getAddress(&Offset));
break;
case DW_CFA_advance_loc1:
// Operands: 1-byte delta
addInstruction(Opcode, Data.getU8(&Offset));
break;
case DW_CFA_advance_loc2:
// Operands: 2-byte delta
addInstruction(Opcode, Data.getU16(&Offset));
break;
case DW_CFA_advance_loc4:
// Operands: 4-byte delta
addInstruction(Opcode, Data.getU32(&Offset));
break;
case DW_CFA_restore_extended:
case DW_CFA_undefined:
case DW_CFA_same_value:
case DW_CFA_def_cfa_register:
case DW_CFA_def_cfa_offset:
// Operands: ULEB128
addInstruction(Opcode, Data.getULEB128(&Offset));
break;
case DW_CFA_def_cfa_offset_sf:
// Operands: SLEB128
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));
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));
break;
case DW_CFA_def_cfa_expression:
case DW_CFA_expression:
case DW_CFA_val_expression:
// TODO: implement this
report_fatal_error("Values with expressions not implemented yet!");
}
}
}
}
void FrameEntry::dumpInstructions(raw_ostream &OS) const {
// TODO: at the moment only instruction names are dumped. Expand this to
// dump operands as well.
for (std::vector<Instruction>::const_iterator I = Instructions.begin(),
E = Instructions.end();
I != E; ++I) {
uint8_t Opcode = I->Opcode;
if (Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK)
Opcode &= DWARF_CFI_PRIMARY_OPCODE_MASK;
OS << " " << CallFrameString(Opcode) << ":\n";
}
}
namespace {
/// \brief DWARF Common Information Entry (CIE)
class CIE : public FrameEntry {
@ -69,9 +220,12 @@ public:
<< "\n";
OS << format(" Version: %d\n", Version);
OS << " Augmentation: \"" << Augmentation << "\"\n";
OS << format(" Code alignment factor: %u\n", (uint32_t)CodeAlignmentFactor);
OS << format(" Data alignment factor: %d\n", (int32_t)DataAlignmentFactor);
OS << format(" Return address column: %d\n", (int32_t)ReturnAddressRegister);
OS << format(" Code alignment factor: %u\n",
(uint32_t)CodeAlignmentFactor);
OS << format(" Data alignment factor: %d\n",
(int32_t)DataAlignmentFactor);
OS << format(" Return address column: %d\n",
(int32_t)ReturnAddressRegister);
OS << "\n";
}
@ -111,7 +265,6 @@ public:
(int32_t)LinkedCIEOffset,
(uint32_t)InitialLocation,
(uint32_t)InitialLocation + (uint32_t)AddressRange);
OS << "\n";
if (LinkedCIE) {
OS << format("%p\n", LinkedCIE);
}
@ -208,7 +361,15 @@ void DWARFDebugFrame::parse(DataExtractor Data) {
Entries.push_back(NewFDE);
}
Offset = EndStructureOffset;
Entries.back()->parseInstructions(Offset, EndStructureOffset);
if (Offset != EndStructureOffset) {
std::string Str;
raw_string_ostream OS(Str);
OS << format("Parsing entry instructions at %lx failed",
Entries.back()->getOffset());
report_fatal_error(Str);
}
}
}
@ -217,7 +378,10 @@ void DWARFDebugFrame::dump(raw_ostream &OS) const {
OS << "\n";
for (EntryVector::const_iterator I = Entries.begin(), E = Entries.end();
I != E; ++I) {
(*I)->dumpHeader(OS);
FrameEntry *Entry = *I;
Entry->dumpHeader(OS);
Entry->dumpInstructions(OS);
OS << "\n";
}
}

1
lib/Support/Dwarf.cpp
View File

@ -688,6 +688,7 @@ const char *llvm::dwarf::MacinfoString(unsigned Encoding) {
/// encodings.
const char *llvm::dwarf::CallFrameString(unsigned Encoding) {
switch (Encoding) {
case DW_CFA_nop: return "DW_CFA_nop";
case DW_CFA_advance_loc: return "DW_CFA_advance_loc";
case DW_CFA_offset: return "DW_CFA_offset";
case DW_CFA_restore: return "DW_CFA_restore";

13
test/DebugInfo/dwarfdump-debug-frame-simple.test
View File

@ -6,9 +6,22 @@
; FRAMES: 00000000 00000010 ffffffff CIE
; FRAMES: Version: 1
; FRAMES: DW_CFA_def_cfa
; FRAMES-NEXT: DW_CFA_offset
; FRAMES-NEXT: DW_CFA_nop
; FRAMES-NEXT: DW_CFA_nop
; FRAMES: 00000014 00000010 00000000 FDE cie=00000000 pc=00000000...00000022
; FRAMES: DW_CFA_advance_loc
; FRAMES-NEXT: DW_CFA_def_cfa_offset
; FRAMES-NEXT: DW_CFA_nop
; FRAMES: 00000028 00000014 00000000 FDE cie=00000000 pc=00000030...00000080
; FRAMES: DW_CFA_advance_loc
; FRAMES-NEXT: DW_CFA_def_cfa_offset
; FRAMES-NEXT: DW_CFA_offset
; FRAMES-NEXT: DW_CFA_advance_loc
; FRAMES-NEXT: DW_CFA_def_cfa_register
; FRAMES-NOT: CIE
; FRAMES-NOT: FDE