Recommit r348806: DebugInfo: Use symbol difference for CU length to simplify assembly reading/editing
Mucking about simplifying a test case ( https://reviews.llvm.org/D55261 ) I stumbled across something I've hit before - that LLVM's (GCC's does too, FWIW) assembly output includes a hardcode length for a DWARF unit in its header. Instead we could emit a label difference - making the assembly easier to read/edit (though potentially at a slight (I haven't tried to observe it) performance cost of delaying/sinking the length computation into the MC layer).
Fix: Predicated all the changes (including creating the labels, even if they aren't used/needed) behind the NVPTX useSectionsAsReferences, avoiding emitting labels in NVPTX where ptxas can't parse them.
Reviewers: JDevlieghere, probinson, ABataev
Differential Revision: https://reviews.llvm.org/D55281
llvm-svn: 349430
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index c5cb7e1..a59ebb7 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -49,6 +49,9 @@
/// Target of Dwarf emission.
AsmPrinter *Asm;
+ /// Emitted at the end of the CU and used to compute the CU Length field.
+ MCSymbol *EndLabel = nullptr;
+
// Holders for some common dwarf information.
DwarfDebug *DD;
DwarfFile *DU;
@@ -82,6 +85,7 @@
public:
// Accessors.
AsmPrinter* getAsmPrinter() const { return Asm; }
+ MCSymbol *getEndLabel() const { return EndLabel; }
uint16_t getLanguage() const { return CUNode->getSourceLanguage(); }
const DICompileUnit *getCUNode() const { return CUNode; }