[DebugInfo] Fix emitting offsets to CUs with -dwarf-sections-as-references=Enable.

The size of the field depends on the DWARF format, not the address size
of the target.

Differential Revision: https://reviews.llvm.org/D82311

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
index 2a8ab09..d81a9be 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
@@ -181,7 +181,8 @@ void AsmPrinter::emitDwarfStringOffset(DwarfStringPoolEntry S) const {
 }
 
 void AsmPrinter::emitDwarfOffset(const MCSymbol *Label, uint64_t Offset) const {
-  emitLabelPlusOffset(Label, Offset, MAI->getCodePointerSize());
+  // TODO: Support DWARF64
+  emitLabelPlusOffset(Label, Offset, 4);
 }
 
 void AsmPrinter::emitCallSiteOffset(const MCSymbol *Hi, const MCSymbol *Lo,

diff --git a/llvm/test/DebugInfo/X86/sections-as-references-cu-offset.ll b/llvm/test/DebugInfo/X86/sections-as-references-cu-offset.ll
new file mode 100644 (file)
index 0000000..6349698
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/sections-as-references-cu-offset.ll
@@ -0,0 +1,27 @@
+; Test that references to CU are 4 bytes long when the target is 64-bit
+; and -dwarf-sections-as-references=Enable is specified.
+
+; RUN: llc -filetype=asm -mtriple=x86_64-linux-gnu -dwarf-sections-as-references=Enable < %s \
+; RUN:   | FileCheck %s
+
+; CHECK: .section .debug_pubnames
+; CHECK: .long .debug_info      # Offset of Compilation Unit Info
+; CHECK: .section .debug_pubtypes
+; CHECK: .long .debug_info      # Offset of Compilation Unit Info
+
+%struct.foo = type { i8 }
+
+@f = global %struct.foo zeroinitializer, align 1, !dbg !0
+
+!llvm.dbg.cu = !{!5}
+!llvm.module.flags = !{!8}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = !DIGlobalVariable(name: "f", scope: null, file: !2, line: 2, type: !3, isLocal: false, isDefinition: true)
+!2 = !DIFile(filename: "tu1.cpp", directory: "/dir")
+!3 = !DICompositeType(tag: DW_TAG_structure_type, name: "foo", file: !2, line: 1, size: 8, align: 8, elements: !4, identifier: "_ZTS3foo")
+!4 = !{}
+!5 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, retainedTypes: !6, globals: !7, imports: !4)
+!6 = !{!3}
+!7 = !{!0}
+!8 = !{i32 1, !"Debug Info Version", i32 3}