Debug Info: use DW_FORM_ref_addr instead of DW_FORM_ref4 if the referenced DIE
belongs to a different compile unit.
DW_FORM_ref_addr should be used for cross compile-unit reference.
When compiling a large application, we got a dwarfdump verification error where
abstract_origin points to nowhere.
This error can't be reproduced on any testing case in MultiSource.
We may have other cases where we use DW_FORM_ref4 unconditionally.
rdar://problem/13370501
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176882 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 30bfa78..2da0bb3 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -352,11 +352,16 @@
// If we're updating an abstract DIE, then we will be adding the children and
// object pointer later on. But what we don't want to do is process the
// concrete DIE twice.
- if (DIE *AbsSPDIE = AbstractSPDies.lookup(SPNode)) {
+ DIE *AbsSPDIE = AbstractSPDies.lookup(SPNode);
+ if (AbsSPDIE) {
+ bool InSameCU = (AbsSPDIE->getCompileUnit() == SPCU->getCUDie());
// Pick up abstract subprogram DIE.
SPDie = new DIE(dwarf::DW_TAG_subprogram);
+ // If AbsSPDIE belongs to a different CU, use DW_FORM_ref_addr instead of
+ // DW_FORM_ref4.
SPCU->addDIEEntry(SPDie, dwarf::DW_AT_abstract_origin,
- dwarf::DW_FORM_ref4, AbsSPDIE);
+ InSameCU ? dwarf::DW_FORM_ref4 : dwarf::DW_FORM_ref_addr,
+ AbsSPDIE);
SPCU->addDie(SPDie);
} else {
DISubprogram SPDecl = SP.getFunctionDeclaration();
@@ -1692,15 +1697,19 @@
// Compute the size and offset of all the DIEs.
void DwarfUnits::computeSizeAndOffsets() {
+ // Offset from the beginning of debug info section.
+ unsigned AccuOffset = 0;
for (SmallVector<CompileUnit *, 1>::iterator I = CUs.begin(),
E = CUs.end(); I != E; ++I) {
+ (*I)->setDebugInfoOffset(AccuOffset);
unsigned Offset =
sizeof(int32_t) + // Length of Compilation Unit Info
sizeof(int16_t) + // DWARF version number
sizeof(int32_t) + // Offset Into Abbrev. Section
sizeof(int8_t); // Pointer Size (in bytes)
- computeSizeAndOffset((*I)->getCUDie(), Offset);
+ unsigned EndOffset = computeSizeAndOffset((*I)->getCUDie(), Offset);
+ AccuOffset += EndOffset;
}
}
@@ -1774,6 +1783,13 @@
DIEEntry *E = cast<DIEEntry>(Values[i]);
DIE *Origin = E->getEntry();
unsigned Addr = Origin->getOffset();
+ if (Form == dwarf::DW_FORM_ref_addr) {
+ // For DW_FORM_ref_addr, output the offset from beginning of debug info
+ // section. Origin->getOffset() returns the offset from start of the
+ // compile unit.
+ DwarfUnits &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
+ Addr += Holder.getCUOffset(Origin->getCompileUnit());
+ }
Asm->EmitInt32(Addr);
break;
}
@@ -1871,6 +1887,17 @@
}
}
+/// For a given compile unit DIE, returns offset from beginning of debug info.
+unsigned DwarfUnits::getCUOffset(DIE *Die) {
+ for (SmallVector<CompileUnit *, 1>::iterator I = CUs.begin(),
+ E = CUs.end(); I != E; ++I) {
+ CompileUnit *TheCU = *I;
+ if (TheCU->getCUDie() == Die)
+ return TheCU->getDebugInfoOffset();
+ }
+ return 0;
+}
+
// Emit the debug info section.
void DwarfDebug::emitDebugInfo() {
DwarfUnits &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;