Dwarf: support for LTO where a single object file can have multiple line tables
We generate one line table for each compilation unit in the object file.
Reviewed by Eric and Kevin.
rdar://problem/13067005
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174445 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 967c149..dcaab31 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -662,13 +662,21 @@
// 2.17.1 requires that we use DW_AT_low_pc for a single entry point
// into an entity. We're using 0 (or a NULL label) for this.
NewCU->addLabelAddress(Die, dwarf::DW_AT_low_pc, NULL);
+
+ // Define start line table label for each Compile Unit.
+ MCSymbol *LineTableStartSym = Asm->GetTempSymbol("line_table_start",
+ NewCU->getUniqueID());
+ Asm->OutStreamer.getContext().setMCLineTableSymbol(LineTableStartSym,
+ NewCU->getUniqueID());
+
// DW_AT_stmt_list is a offset of line number information for this
// compile unit in debug_line section.
if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
NewCU->addLabel(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4,
- Asm->GetTempSymbol("section_line"));
+ LineTableStartSym);
else
- NewCU->addUInt(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4, 0);
+ NewCU->addDelta(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4,
+ LineTableStartSym, Asm->GetTempSymbol("section_line"));
if (!CompilationDir.empty())
NewCU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
@@ -1399,6 +1407,13 @@
if (LScopes.empty()) return;
identifyScopeMarkers();
+ // Set DwarfCompileUnitID in MCContext to the Compile Unit this function
+ // belongs to.
+ LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
+ CompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
+ assert(TheCU && "Unable to find compile unit!");
+ Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
+
FunctionBeginSym = Asm->GetTempSymbol("func_begin",
Asm->getFunctionNumber());
// Assumes in correct section after the entry point.
@@ -1583,6 +1598,8 @@
Asm->getFunctionNumber());
// Assumes in correct section after the entry point.
Asm->OutStreamer.EmitLabel(FunctionEndSym);
+ // Set DwarfCompileUnitID in MCContext to default value.
+ Asm->OutStreamer.getContext().setDwarfCompileUnitID(0);
SmallPtrSet<const MDNode *, 16> ProcessedVars;
collectVariableInfo(MF, ProcessedVars);