[DWARF parser] Make DWARF parser more robust against missing compile/type units.
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.
llvm-svn: 237733
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp
index 01e7247..39a7c77 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp
@@ -22,9 +22,10 @@
<< " (next unit at " << format("0x%08x", getNextUnitOffset())
<< ")\n";
- const DWARFDebugInfoEntryMinimal *CU = getCompileUnitDIE(false);
- assert(CU && "Null Compile Unit?");
- CU->dump(OS, this, -1U);
+ if (const DWARFDebugInfoEntryMinimal *CU = getUnitDIE(false))
+ CU->dump(OS, this, -1U);
+ else
+ OS << "<compile unit can't be parsed!>\n\n";
}
// VTable anchor.
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index 3b42700..1faa2ba 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -140,9 +140,11 @@
OS << "\n.debug_line contents:\n";
for (const auto &CU : compile_units()) {
savedAddressByteSize = CU->getAddressByteSize();
- unsigned stmtOffset =
- CU->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
- CU.get(), DW_AT_stmt_list, -1U);
+ const auto *CUDIE = CU->getUnitDIE();
+ if (CUDIE == nullptr)
+ continue;
+ unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
+ CU.get(), DW_AT_stmt_list, -1U);
if (stmtOffset != -1U) {
DataExtractor lineData(getLineSection().Data, isLittleEndian(),
savedAddressByteSize);
@@ -321,13 +323,14 @@
}
const DWARFLineTable *
-DWARFContext::getLineTableForUnit(DWARFUnit *cu) {
+DWARFContext::getLineTableForUnit(DWARFUnit *U) {
if (!Line)
Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
-
+ const auto *UnitDIE = U->getUnitDIE();
+ if (UnitDIE == nullptr)
+ return nullptr;
unsigned stmtOffset =
- cu->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
- cu, DW_AT_stmt_list, -1U);
+ UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U);
if (stmtOffset == -1U)
return nullptr; // No line table for this compile unit.
@@ -337,7 +340,7 @@
// We have to parse it first.
DataExtractor lineData(getLineSection().Data, isLittleEndian(),
- cu->getAddressByteSize());
+ U->getAddressByteSize());
return Line->getOrParseLineTable(lineData, stmtOffset);
}
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
index 65c7bff..766e8ac 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
@@ -33,7 +33,8 @@
<< " (next unit at " << format("0x%08x", getNextUnitOffset())
<< ")\n";
- const DWARFDebugInfoEntryMinimal *CU = getCompileUnitDIE(false);
- assert(CU && "Null Compile Unit?");
- CU->dump(OS, this, -1U);
+ if (const DWARFDebugInfoEntryMinimal *TU = getUnitDIE(false))
+ TU->dump(OS, this, -1U);
+ else
+ OS << "<type unit can't be parsed!>\n\n";
}
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index 406915a..63a9985 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -310,8 +310,11 @@
}
void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
- // First, check if CU DIE describes address ranges for the unit.
- const auto &CUDIERanges = getCompileUnitDIE()->getAddressRanges(this);
+ const auto *U = getUnitDIE();
+ if (U == nullptr)
+ return;
+ // First, check if unit DIE describes address ranges for the whole unit.
+ const auto &CUDIERanges = U->getAddressRanges(this);
if (!CUDIERanges.empty()) {
CURanges.insert(CURanges.end(), CUDIERanges.begin(), CUDIERanges.end());
return;