Re-land "[codeview] Emit information about global variables"
This reverts commit r271962 and reinstantes r271957.
MSVC's linker doesn't appear to like it if you have an empty symbol
substream, so only open a symbol substream if we're going to emit
something about globals into it.
Makes check-asan pass.
llvm-svn: 271965
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 57fa54a..db1dc51 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -232,7 +232,7 @@
}
void CodeViewDebug::endModule() {
- if (FnDebugInfo.empty())
+ if (!Asm || !MMI->hasDebugInfo())
return;
assert(Asm != nullptr);
@@ -242,13 +242,18 @@
// of the payload followed by the payload itself. The subsections are 4-byte
// aligned.
- // Make a subsection for all the inlined subprograms.
+ // Use the generic .debug$S section, and make a subsection for all the inlined
+ // subprograms.
+ switchToDebugSectionForSymbol(nullptr);
emitInlineeLinesSubsection();
// Emit per-function debug information.
for (auto &P : FnDebugInfo)
emitDebugInfoForFunction(P.first, P.second);
+ // Emit global variable debug information.
+ emitDebugInfoForGlobals();
+
// Switch back to the generic .debug$S section after potentially processing
// comdat symbol sections.
switchToDebugSectionForSymbol(nullptr);
@@ -326,17 +331,9 @@
if (InlinedSubprograms.empty())
return;
- // Use the generic .debug$S section.
- switchToDebugSectionForSymbol(nullptr);
-
- MCSymbol *InlineBegin = MMI->getContext().createTempSymbol(),
- *InlineEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Inlinee lines subsection");
- OS.EmitIntValue(unsigned(ModuleSubstreamKind::InlineeLines), 4);
- OS.AddComment("Subsection size");
- OS.emitAbsoluteSymbolDiff(InlineEnd, InlineBegin, 4);
- OS.EmitLabel(InlineBegin);
+ MCSymbol *InlineEnd = beginCVSubsection(ModuleSubstreamKind::InlineeLines);
// We don't provide any extra file info.
// FIXME: Find out if debuggers use this info.
@@ -363,7 +360,7 @@
OS.EmitIntValue(SP->getLine(), 4);
}
- OS.EmitLabel(InlineEnd);
+ endCVSubsection(InlineEnd);
}
void CodeViewDebug::collectInlineSiteChildren(
@@ -467,13 +464,8 @@
FuncName = GlobalValue::getRealLinkageName(GV->getName());
// Emit a symbol subsection, required by VS2012+ to find function boundaries.
- MCSymbol *SymbolsBegin = MMI->getContext().createTempSymbol(),
- *SymbolsEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Symbol subsection for " + Twine(FuncName));
- OS.EmitIntValue(unsigned(ModuleSubstreamKind::Symbols), 4);
- OS.AddComment("Subsection size");
- OS.emitAbsoluteSymbolDiff(SymbolsEnd, SymbolsBegin, 4);
- OS.EmitLabel(SymbolsBegin);
+ MCSymbol *SymbolsEnd = beginCVSubsection(ModuleSubstreamKind::Symbols);
{
MCSymbol *ProcRecordBegin = MMI->getContext().createTempSymbol(),
*ProcRecordEnd = MMI->getContext().createTempSymbol();
@@ -532,9 +524,7 @@
OS.AddComment("Record kind: S_PROC_ID_END");
OS.EmitIntValue(unsigned(SymbolKind::S_PROC_ID_END), 2);
}
- OS.EmitLabel(SymbolsEnd);
- // Every subsection must be aligned to a 4-byte boundary.
- OS.EmitValueToAlignment(4);
+ endCVSubsection(SymbolsEnd);
// We have an assembler directive that takes care of the whole line table.
OS.EmitCVLinetableDirective(FI.FuncId, Fn, FI.End);
@@ -1272,3 +1262,82 @@
return;
maybeRecordLocation(DL, Asm->MF);
}
+
+MCSymbol *CodeViewDebug::beginCVSubsection(ModuleSubstreamKind Kind) {
+ MCSymbol *BeginLabel = MMI->getContext().createTempSymbol(),
+ *EndLabel = MMI->getContext().createTempSymbol();
+ OS.EmitIntValue(unsigned(Kind), 4);
+ OS.AddComment("Subsection size");
+ OS.emitAbsoluteSymbolDiff(EndLabel, BeginLabel, 4);
+ OS.EmitLabel(BeginLabel);
+ return EndLabel;
+}
+
+void CodeViewDebug::endCVSubsection(MCSymbol *EndLabel) {
+ OS.EmitLabel(EndLabel);
+ // Every subsection must be aligned to a 4-byte boundary.
+ OS.EmitValueToAlignment(4);
+}
+
+void CodeViewDebug::emitDebugInfoForGlobals() {
+ NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
+ for (const MDNode *Node : CUs->operands()) {
+ const auto *CU = cast<DICompileUnit>(Node);
+
+ // First, emit all globals that are not in a comdat in a single symbol
+ // substream. MSVC doesn't like it if the substream is empty, so only open
+ // it if we have at least one global to emit.
+ switchToDebugSectionForSymbol(nullptr);
+ MCSymbol *EndLabel = nullptr;
+ for (const DIGlobalVariable *G : CU->getGlobalVariables()) {
+ if (const auto *GV = dyn_cast<GlobalVariable>(G->getVariable()))
+ if (!GV->hasComdat()) {
+ if (!EndLabel) {
+ OS.AddComment("Symbol subsection for globals");
+ EndLabel = beginCVSubsection(ModuleSubstreamKind::Symbols);
+ }
+ emitDebugInfoForGlobal(G, Asm->getSymbol(GV));
+ }
+ }
+ if (EndLabel)
+ endCVSubsection(EndLabel);
+
+ // Second, emit each global that is in a comdat into its own .debug$S
+ // section along with its own symbol substream.
+ for (const DIGlobalVariable *G : CU->getGlobalVariables()) {
+ if (const auto *GV = dyn_cast<GlobalVariable>(G->getVariable())) {
+ if (GV->hasComdat()) {
+ MCSymbol *GVSym = Asm->getSymbol(GV);
+ OS.AddComment("Symbol subsection for " +
+ Twine(GlobalValue::getRealLinkageName(GV->getName())));
+ switchToDebugSectionForSymbol(GVSym);
+ EndLabel = beginCVSubsection(ModuleSubstreamKind::Symbols);
+ emitDebugInfoForGlobal(G, GVSym);
+ endCVSubsection(EndLabel);
+ }
+ }
+ }
+ }
+}
+
+void CodeViewDebug::emitDebugInfoForGlobal(const DIGlobalVariable *DIGV,
+ MCSymbol *GVSym) {
+ // DataSym record, see SymbolRecord.h for more info.
+ // FIXME: Thread local data, etc
+ MCSymbol *DataBegin = MMI->getContext().createTempSymbol(),
+ *DataEnd = MMI->getContext().createTempSymbol();
+ OS.AddComment("Record length");
+ OS.emitAbsoluteSymbolDiff(DataEnd, DataBegin, 2);
+ OS.EmitLabel(DataBegin);
+ OS.AddComment("Record kind: S_GDATA32");
+ OS.EmitIntValue(unsigned(SymbolKind::S_GDATA32), 2);
+ OS.AddComment("Type");
+ OS.EmitIntValue(getCompleteTypeIndex(DIGV->getType()).getIndex(), 4);
+ OS.AddComment("DataOffset");
+ OS.EmitCOFFSecRel32(GVSym);
+ OS.AddComment("Segment");
+ OS.EmitCOFFSectionIndex(GVSym);
+ OS.AddComment("Name");
+ emitNullTerminatedSymbolName(OS, DIGV->getName());
+ OS.EmitLabel(DataEnd);
+}
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
index 208ff33..69c9c96 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
@@ -169,6 +169,17 @@
void emitDebugInfoForFunction(const Function *GV, FunctionInfo &FI);
+ void emitDebugInfoForGlobals();
+
+ void emitDebugInfoForGlobal(const DIGlobalVariable *DIGV, MCSymbol *GVSym);
+
+ /// Opens a subsection of the given kind in a .debug$S codeview section.
+ /// Returns an end label for use with endCVSubsection when the subsection is
+ /// finished.
+ MCSymbol *beginCVSubsection(codeview::ModuleSubstreamKind Kind);
+
+ void endCVSubsection(MCSymbol *EndLabel);
+
void emitInlinedCallSite(const FunctionInfo &FI, const DILocation *InlinedAt,
const InlineSite &Site);