[llvm] r175820 - Previously, parsing capability of the .debug_frame section was added
Eli Bendersky
eliben at google.com
Thu Feb 21 14:53:19 PST 2013
Author: eliben
Date: Thu Feb 21 16:53:19 2013
New Revision: 175820
URL: http://llvm.org/viewvc/llvm-project?rev=175820&view=rev
Log:
Previously, parsing capability of the .debug_frame section was added
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.
Modified:
llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp
llvm/trunk/lib/Support/Dwarf.cpp
llvm/trunk/test/DebugInfo/dwarfdump-debug-frame-simple.test
Modified: llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp?rev=175820&r1=175819&r2=175820&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp (original)
+++ llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp Thu Feb 21 16:53:19 2013
@@ -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(DataExtracto
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 << "\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";
}
}
Modified: llvm/trunk/lib/Support/Dwarf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Dwarf.cpp?rev=175820&r1=175819&r2=175820&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Dwarf.cpp (original)
+++ llvm/trunk/lib/Support/Dwarf.cpp Thu Feb 21 16:53:19 2013
@@ -688,6 +688,7 @@ const char *llvm::dwarf::MacinfoString(u
/// 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";
Modified: llvm/trunk/test/DebugInfo/dwarfdump-debug-frame-simple.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/dwarfdump-debug-frame-simple.test?rev=175820&r1=175819&r2=175820&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/dwarfdump-debug-frame-simple.test (original)
+++ llvm/trunk/test/DebugInfo/dwarfdump-debug-frame-simple.test Thu Feb 21 16:53:19 2013
@@ -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
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