[PATCH] Initial DWARF64 support for .debug_line
Ed Maste
emaste at freebsd.org
Wed Oct 23 08:05:46 PDT 2013
Added comments and a basic test
(Comments are in DWARFContext.h as that seemed to be a more clear reference to the individual classes.)
Hi echristo,
http://llvm-reviews.chandlerc.com/D1988
CHANGE SINCE LAST DIFF
http://llvm-reviews.chandlerc.com/D1988?vs=5061&id=5096#toc
Files:
lib/DebugInfo/DWARFContext.h
lib/DebugInfo/DWARFDebugLine.cpp
lib/DebugInfo/DWARFDebugLine.h
test/DebugInfo/Inputs/dwarfdump-inl-test.elf-mips64-64-bit-dwarf
test/DebugInfo/dwarfdump-64-bit-dwarf.test
Index: lib/DebugInfo/DWARFContext.h
===================================================================
--- lib/DebugInfo/DWARFContext.h
+++ lib/DebugInfo/DWARFContext.h
@@ -27,6 +27,22 @@
/// This data structure is the top level entity that deals with dwarf debug
/// information parsing. The actual data is supplied through pure virtual
/// methods that a concrete implementation provides.
+///
+/// 7.4 32-Bit and 64-Bit DWARF Formats
+/// DWARF Version 3 specifies the 64-Bit format, which uses 0xffffffff in
+/// the 32-bit initial length field to signal that the actual length and
+/// later offsets are 64-Bit. Partial support is implemented to handle
+/// 64-Bit DWARF emitted by some toolchains, even though it is not
+/// actually necessary (the debug data is not > 4GB).
+///
+/// Class 64-bit support Notes
+/// DataExtractor No Prevents handling debug data >4GB
+/// DWARFDebugAbbrev No
+/// DWARFDebugLoc No
+/// DWARFDebugAranges No
+/// DWARFDebugLine Yes
+/// DWARFDebugFrame Yes
+///
class DWARFContext : public DIContext {
SmallVector<DWARFCompileUnit *, 1> CUs;
SmallVector<DWARFTypeUnit *, 1> TUs;
Index: lib/DebugInfo/DWARFDebugLine.cpp
===================================================================
--- lib/DebugInfo/DWARFDebugLine.cpp
+++ lib/DebugInfo/DWARFDebugLine.cpp
@@ -18,9 +18,9 @@
void DWARFDebugLine::Prologue::dump(raw_ostream &OS) const {
OS << "Line table prologue:\n"
- << format(" total_length: 0x%8.8x\n", TotalLength)
+ << format(" total_length: 0x%8.8" PRIx64 "\n", TotalLength)
<< format(" version: %u\n", Version)
- << format("prologue_length: 0x%8.8x\n", PrologueLength)
+ << format("prologue_length: 0x%8.8" PRIx64 "\n", PrologueLength)
<< format("min_inst_length: %u\n", MinInstLength)
<< format("default_is_stmt: %u\n", DefaultIsStmt)
<< format(" line_base: %i\n", LineBase)
@@ -165,16 +165,23 @@
bool
DWARFDebugLine::parsePrologue(DataExtractor debug_line_data,
uint32_t *offset_ptr, Prologue *prologue) {
- const uint32_t prologue_offset = *offset_ptr;
+ const uint64_t prologue_offset = *offset_ptr;
prologue->clear();
prologue->TotalLength = debug_line_data.getU32(offset_ptr);
+ if (prologue->TotalLength == UINT32_MAX) {
+ prologue->IsDWARF64 = true;
+ prologue->TotalLength = debug_line_data.getU64(offset_ptr);
+ } else if (prologue->TotalLength >= 0xffffff00) {
+ return false;
+ }
prologue->Version = debug_line_data.getU16(offset_ptr);
if (prologue->Version != 2)
return false;
- prologue->PrologueLength = debug_line_data.getU32(offset_ptr);
- const uint32_t end_prologue_offset = prologue->PrologueLength + *offset_ptr;
+ prologue->PrologueLength = debug_line_data.getUnsigned(offset_ptr,
+ prologue->sizeofPrologueLength());
+ const uint64_t end_prologue_offset = prologue->PrologueLength + *offset_ptr;
prologue->MinInstLength = debug_line_data.getU8(offset_ptr);
prologue->DefaultIsStmt = debug_line_data.getU8(offset_ptr);
prologue->LineBase = debug_line_data.getU8(offset_ptr);
@@ -209,10 +216,15 @@
}
}
- if (*offset_ptr != end_prologue_offset) {
- fprintf(stderr, "warning: parsing line table prologue at 0x%8.8x should"
- " have ended at 0x%8.8x but it ended at 0x%8.8x\n",
- prologue_offset, end_prologue_offset, *offset_ptr);
+ if (prologue->IsDWARF64 && end_prologue_offset - *offset_ptr == 12) {
+ fprintf(stderr, "warning: apparent 64-bit DWARF GNU as prologue length bug"
+ " detected (prologue length 12 bytes too long)\n");
+ // Could correct the field: prologue->PrologueLength -= 12;
+ } else if (*offset_ptr != end_prologue_offset) {
+ fprintf(stderr, "warning: parsing line table prologue at 0x%8.8" PRIx64
+ " should have ended at 0x%8.8" PRIx64
+ " but it ended at 0x%8.8" PRIx64 "\n",
+ prologue_offset, end_prologue_offset, (uint64_t)*offset_ptr);
return false;
}
return true;
@@ -233,7 +245,7 @@
}
const uint32_t end_offset = debug_line_offset + prologue->TotalLength +
- sizeof(prologue->TotalLength);
+ prologue->sizeofTotalLength();
state.reset();
Index: lib/DebugInfo/DWARFDebugLine.h
===================================================================
--- lib/DebugInfo/DWARFDebugLine.h
+++ lib/DebugInfo/DWARFDebugLine.h
@@ -35,16 +35,17 @@
struct Prologue {
Prologue()
: TotalLength(0), Version(0), PrologueLength(0), MinInstLength(0),
- DefaultIsStmt(0), LineBase(0), LineRange(0), OpcodeBase(0) {}
+ DefaultIsStmt(0), LineBase(0), LineRange(0), OpcodeBase(0),
+ IsDWARF64(false) {}
// The size in bytes of the statement information for this compilation unit
// (not including the total_length field itself).
- uint32_t TotalLength;
+ uint64_t TotalLength;
// Version identifier for the statement information format.
uint16_t Version;
// The number of bytes following the prologue_length field to the beginning
// of the first byte of the statement program itself.
- uint32_t PrologueLength;
+ uint64_t PrologueLength;
// The size in bytes of the smallest target machine instruction. Statement
// program opcodes that alter the address register first multiply their
// operands by this value.
@@ -61,14 +62,22 @@
std::vector<const char*> IncludeDirectories;
std::vector<FileNameEntry> FileNames;
+ bool IsDWARF64;
+ uint32_t sizeofTotalLength() const {
+ return IsDWARF64 ? 12 : 4;
+ }
+ uint32_t sizeofPrologueLength() const {
+ return IsDWARF64 ? 8 : 4;
+ }
+
// Length of the prologue in bytes.
uint32_t getLength() const {
- return PrologueLength + sizeof(TotalLength) + sizeof(Version) +
- sizeof(PrologueLength);
+ return PrologueLength + sizeofTotalLength() + sizeof(Version) +
+ sizeofPrologueLength();
}
// Length of the line table data in bytes (not including the prologue).
uint32_t getStatementTableLength() const {
- return TotalLength + sizeof(TotalLength) - getLength();
+ return TotalLength + sizeofTotalLength() - getLength();
}
int32_t getMaxLineIncrementForSpecialOpcode() const {
return LineBase + (int8_t)LineRange - 1;
@@ -80,6 +89,7 @@
StandardOpcodeLengths.clear();
IncludeDirectories.clear();
FileNames.clear();
+ IsDWARF64 = false;
}
};
Index: test/DebugInfo/dwarfdump-64-bit-dwarf.test
===================================================================
--- /dev/null
+++ test/DebugInfo/dwarfdump-64-bit-dwarf.test
@@ -0,0 +1,12 @@
+RUN: llvm-dwarfdump %p/Inputs/dwarfdump-inl-test.elf-mips64-64-bit-dwarf \
+RUN: --debug-dump=line | FileCheck %s
+
+CHECK: total_length: 0x00000212
+CHECK: version: 2
+CHECK:prologue_length: 0x000001ab
+CHECK:min_inst_length: 1
+CHECK:default_is_stmt: 1
+CHECK: line_base: -5
+CHECK: line_range: 14
+CHECK: opcode_base: 13
+CHECK: is_stmt end_sequence
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