Add initial support for handling gnu style pubnames accepted by some
versions of gold. This support is designed to allow gold to produce
gdb_index sections similar to the accelerator tables and consumable
by gdb.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190649 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index f155647..4f62ab9 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -68,6 +68,11 @@
cl::desc("Add the CU hash as the dwo_id."),
cl::init(false));
+static cl::opt<bool>
+GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden,
+ cl::desc("Generate GNU-style pubnames and pubtypes"),
+ cl::init(false));
+
namespace {
enum DefaultOnOff {
Default,
@@ -768,6 +773,12 @@
// skeleton CU and so we don't need to duplicate it here.
if (!useSplitDwarf() && !CompilationDir.empty())
NewCU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
+
+ // Flag to let the linker know we have emitted new style pubnames. Only
+ // emit it here if we don't have a skeleton CU for split dwarf.
+ if (!useSplitDwarf() && GenerateGnuPubSections)
+ NewCU->addFlag(Die, dwarf::DW_AT_GNU_pubnames);
+
if (DIUnit.isOptimized())
NewCU->addFlag(Die, dwarf::DW_AT_APPLE_optimized);
@@ -1149,8 +1160,8 @@
// Emit the pubnames and pubtypes sections if requested.
if (HasDwarfPubSections) {
- emitDebugPubNames();
- emitDebugPubTypes();
+ emitDebugPubNames(GenerateGnuPubSections ? true : false);
+ emitDebugPubTypes(GenerateGnuPubSections ? true : false);
}
// Finally emit string information into a string table.
@@ -1933,7 +1944,11 @@
if (HasDwarfPubSections) {
emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
+ } else if (GenerateGnuPubSections) {
+ emitSectionSym(Asm, TLOF.getDwarfGnuPubNamesSection());
+ emitSectionSym(Asm, TLOF.getDwarfGnuPubTypesSection());
}
+
DwarfStrSectionSym =
emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
if (useSplitDwarf()) {
@@ -2292,11 +2307,83 @@
AT.Emit(Asm, SectionBegin, &InfoHolder);
}
+// Public name handling.
+// The format for the various pubnames:
+//
+// dwarf pubnames - offset/name pairs where the offset is the offset into the CU
+// for the DIE that is named.
+//
+// gnu pubnames - offset/index value/name tuples where the offset is the offset
+// into the CU and the index value is computed according to the type of value
+// for the DIE that is named.
+//
+// For type units the offset is the offset of the skeleton DIE. For split dwarf
+// it's the offset within the debug_info/debug_types dwo section, however, the
+// reference in the pubname header doesn't change.
+
+/// computeIndexValue - Compute the gdb index value for the DIE and CU.
+static uint8_t computeIndexValue(CompileUnit *CU, DIE *Die) {
+#define UPDATE_VALUE(CURRENT, VALUE) \
+ { \
+ (CURRENT) |= (((VALUE) & dwarf::GDB_INDEX_SYMBOL_KIND_MASK) \
+ << dwarf::GDB_INDEX_SYMBOL_KIND_SHIFT); \
+ }
+
+#define UPDATE_STATIC(CURRENT, IS_STATIC) \
+ { \
+ (CURRENT) |= (((IS_STATIC) & dwarf::GDB_INDEX_SYMBOL_STATIC_MASK) \
+ << dwarf::GDB_INDEX_SYMBOL_STATIC_SHIFT); \
+ }
+
+ // Compute the Attributes for the Die.
+ uint32_t Value = dwarf::GDB_INDEX_SYMBOL_KIND_NONE;
+ bool External =
+ Die->findAttribute(dwarf::DW_AT_external) != NULL ? true : false;
+
+ switch (Die->getTag()) {
+ case dwarf::DW_TAG_class_type:
+ case dwarf::DW_TAG_structure_type:
+ case dwarf::DW_TAG_union_type:
+ case dwarf::DW_TAG_enumeration_type:
+ case dwarf::DW_TAG_typedef:
+ case dwarf::DW_TAG_base_type:
+ case dwarf::DW_TAG_subrange_type:
+ UPDATE_VALUE(Value, dwarf::GDB_INDEX_SYMBOL_KIND_TYPE);
+ UPDATE_STATIC(Value, 1);
+ break;
+ case dwarf::DW_TAG_namespace:
+ UPDATE_VALUE(Value, dwarf::GDB_INDEX_SYMBOL_KIND_TYPE);
+ break;
+ case dwarf::DW_TAG_subprogram:
+ UPDATE_VALUE(Value, dwarf::GDB_INDEX_SYMBOL_KIND_FUNCTION);
+ UPDATE_STATIC(Value, !External);
+ break;
+ case dwarf::DW_TAG_constant:
+ case dwarf::DW_TAG_variable:
+ UPDATE_VALUE(Value, dwarf::GDB_INDEX_SYMBOL_KIND_VARIABLE);
+ UPDATE_STATIC(Value, !External);
+ break;
+ case dwarf::DW_TAG_enumerator:
+ UPDATE_VALUE(Value, dwarf::GDB_INDEX_SYMBOL_KIND_VARIABLE);
+ UPDATE_STATIC(Value, 1);
+ break;
+ default:
+ break;
+ }
+ // We don't need to add the CU into the bitmask for two reasons:
+ // a) the pubnames/pubtypes sections are per-cpu, and
+ // b) the linker wouldn't understand it anyhow.
+ // so go ahead and make it 1 byte by shifting it down.
+ return Value >> dwarf::GDB_INDEX_CU_BITSIZE;
+}
+
/// emitDebugPubNames - Emit visible names into a debug pubnames section.
///
-void DwarfDebug::emitDebugPubNames() {
+void DwarfDebug::emitDebugPubNames(bool GnuStyle) {
const MCSection *ISec = Asm->getObjFileLowering().getDwarfInfoSection();
- const MCSection *PSec = Asm->getObjFileLowering().getDwarfPubNamesSection();
+ const MCSection *PSec =
+ GnuStyle ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection()
+ : Asm->getObjFileLowering().getDwarfPubNamesSection();
typedef DenseMap<const MDNode*, CompileUnit*> CUMapType;
for (CUMapType::iterator I = CUMap.begin(), E = CUMap.end(); I != E; ++I) {
@@ -2309,6 +2396,7 @@
// Start the dwarf pubnames section.
Asm->OutStreamer.SwitchSection(PSec);
+ // Emit the header.
Asm->OutStreamer.AddComment("Length of Public Names Info");
Asm->EmitLabelDifference(Asm->GetTempSymbol("pubnames_end", ID),
Asm->GetTempSymbol("pubnames_begin", ID), 4);
@@ -2327,15 +2415,21 @@
Asm->GetTempSymbol(ISec->getLabelBeginName(), ID),
4);
+ // Emit the pubnames for this compilation unit.
const StringMap<DIE*> &Globals = TheCU->getGlobalNames();
for (StringMap<DIE*>::const_iterator
GI = Globals.begin(), GE = Globals.end(); GI != GE; ++GI) {
const char *Name = GI->getKeyData();
- const DIE *Entity = GI->second;
+ DIE *Entity = GI->second;
Asm->OutStreamer.AddComment("DIE offset");
Asm->EmitInt32(Entity->getOffset());
+ if (GnuStyle) {
+ Asm->OutStreamer.AddComment("Index value");
+ Asm->EmitInt8(computeIndexValue(TheCU, Entity));
+ }
+
if (Asm->isVerbose())
Asm->OutStreamer.AddComment("External Name");
Asm->OutStreamer.EmitBytes(StringRef(Name, GI->getKeyLength()+1));
@@ -2347,7 +2441,7 @@
}
}
-void DwarfDebug::emitDebugPubTypes() {
+void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
const MCSection *ISec = Asm->getObjFileLowering().getDwarfInfoSection();
const MCSection *PSec = Asm->getObjFileLowering().getDwarfPubTypesSection();
@@ -2390,6 +2484,11 @@
Asm->OutStreamer.AddComment("DIE offset");
Asm->EmitInt32(Entity->getOffset());
+ if (GnuStyle) {
+ Asm->OutStreamer.AddComment("Index value");
+ Asm->EmitInt8(computeIndexValue(TheCU, Entity));
+ }
+
if (Asm->isVerbose())
Asm->OutStreamer.AddComment("External Name");
@@ -2651,6 +2750,10 @@
if (!CompilationDir.empty())
NewCU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
+ // Flag to let the linker know we have emitted new style pubnames.
+ if (GenerateGnuPubSections)
+ NewCU->addFlag(Die, dwarf::DW_AT_GNU_pubnames);
+
SkeletonHolder.addUnit(NewCU);
SkeletonCUs.push_back(NewCU);
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index c702180..5a03e9f 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -533,10 +533,16 @@
void emitAccelTypes();
/// \brief Emit visible names into a debug pubnames section.
- void emitDebugPubNames();
+ /// \param GnuStyle determines whether or not we want to emit
+ /// additional information into the table ala newer gcc for gdb
+ /// index.
+ void emitDebugPubNames(bool GnuStyle = false);
/// \brief Emit visible types into a debug pubtypes section.
- void emitDebugPubTypes();
+ /// \param GnuStyle determines whether or not we want to emit
+ /// additional information into the table ala newer gcc for gdb
+ /// index.
+ void emitDebugPubTypes(bool GnuStyle = false);
/// \brief Emit visible names into a debug str section.
void emitDebugStr();