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[DWARF parser] Make DWARF parser more robust against missing compile/type units.

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DWARF standard claims that each compilation/type unit header in
.debug_info/.debug_types section must be followed by corresponding
compile/type unit DIE, possibly with its children. Two situations
are possible:

 * compile/type unit DIE is missing because DWARF producer failed to
   emit it.
 * DWARF parser failed to parse unit DIE correctly, for instance if it
   contains some unsupported attributes (see r237721, for instance).

In either of these cases, the library, and the tools that use it
(llvm-dwarfdump, llvm-symbolizer) should not crash. Insert appropriate
checks to protect against this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237733 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alexey Samsonov
2015-05-19 21:54:32 +00:00
parent b9b3fb261e
commit 05f725eb67
6 changed files with 33 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
tools/dsymutil/DwarfLinker.cpp
View File

@@ -729,7 +729,7 @@ void DwarfStreamer::emitLocationsForUnit(const CompileUnit &Unit,
const DWARFSection &InputSec = Dwarf.getLocSection();
DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(), AddressSize);
DWARFUnit &OrigUnit = Unit.getOrigUnit();
const auto *OrigUnitDie = OrigUnit.getCompileUnitDIE(false);
const auto *OrigUnitDie = OrigUnit.getUnitDIE(false);
int64_t UnitPcOffset = 0;
uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress(
&OrigUnit, dwarf::DW_AT_low_pc, -1ULL);
@@ -2203,7 +2203,7 @@ void DwarfLinker::patchRangesForUnit(const CompileUnit &Unit,
OrigDwarf.isLittleEndian(), AddressSize);
auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange;
DWARFUnit &OrigUnit = Unit.getOrigUnit();
const auto *OrigUnitDie = OrigUnit.getCompileUnitDIE(false);
const auto *OrigUnitDie = OrigUnit.getUnitDIE(false);
uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress(
&OrigUnit, dwarf::DW_AT_low_pc, -1ULL);
// Ranges addresses are based on the unit's low_pc. Compute the
@@ -2287,7 +2287,7 @@ static void insertLineSequence(std::vector<DWARFDebugLine::Row> &Seq,
void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
DWARFContext &OrigDwarf) {
const DWARFDebugInfoEntryMinimal *CUDie =
Unit.getOrigUnit().getCompileUnitDIE();
Unit.getOrigUnit().getUnitDIE();
uint64_t StmtList = CUDie->getAttributeValueAsSectionOffset(
&Unit.getOrigUnit(), dwarf::DW_AT_stmt_list, -1ULL);
if (StmtList == -1ULL)
@@ -2461,7 +2461,7 @@ bool DwarfLinker::link(const DebugMap &Map) {
// In a first phase, just read in the debug info and store the DIE
// parent links that we will use during the next phase.
for (const auto &CU : DwarfContext.compile_units()) {
auto *CUDie = CU->getCompileUnitDIE(false);
auto *CUDie = CU->getUnitDIE(false);
if (Options.Verbose) {
outs() << "Input compilation unit:";
CUDie->dump(outs(), CU.get(), 0);
@@ -2476,7 +2476,7 @@ bool DwarfLinker::link(const DebugMap &Map) {
// references require the ParentIdx to be setup for every CU in
// the object file before calling this.
for (auto &CurrentUnit : Units)
lookForDIEsToKeep(*CurrentUnit.getOrigUnit().getCompileUnitDIE(), *Obj,
lookForDIEsToKeep(*CurrentUnit.getOrigUnit().getUnitDIE(), *Obj,
CurrentUnit, 0);
// The calls to applyValidRelocs inside cloneDIE will walk the
@@ -2489,7 +2489,7 @@ bool DwarfLinker::link(const DebugMap &Map) {
// to clone/emit.
if (!ValidRelocs.empty())
for (auto &CurrentUnit : Units) {
const auto *InputDIE = CurrentUnit.getOrigUnit().getCompileUnitDIE();
const auto *InputDIE = CurrentUnit.getOrigUnit().getUnitDIE();
CurrentUnit.setStartOffset(OutputDebugInfoSize);
DIE *OutputDIE = cloneDIE(*InputDIE, CurrentUnit, 0 /* PCOffset */,
11 /* Unit Header size */);