[PATCH] D42527: [DebugInfo] Fix fragment offset emission order for symbol locations

[Mikael Holmén via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL323644: [DebugInfo] Fix fragment offset emission order for symbol locations (authored by uabelho, committed by ).

Changed prior to commit:
  https://reviews.llvm.org/D42527?vs=131414&id=131769#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D42527

Files:
  llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
  llvm/trunk/test/DebugInfo/X86/fragment-offset-order.ll


Index: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -191,6 +191,9 @@
       DwarfExpr = llvm::make_unique<DIEDwarfExpression>(*Asm, *this, *Loc);
     }
 
+    if (Expr)
+      DwarfExpr->addFragmentOffset(Expr);
+
     if (Global) {
       const MCSymbol *Sym = Asm->getSymbol(Global);
       if (Global->isThreadLocal()) {
@@ -226,10 +229,8 @@
         addOpAddress(*Loc, Sym);
       }
     }
-    if (Expr) {
-      DwarfExpr->addFragmentOffset(Expr);
+    if (Expr)
       DwarfExpr->addExpression(Expr);
-    }
   }
   if (Loc)
     addBlock(*VariableDIE, dwarf::DW_AT_location, DwarfExpr->finalize());
Index: llvm/trunk/test/DebugInfo/X86/fragment-offset-order.ll
===================================================================
--- llvm/trunk/test/DebugInfo/X86/fragment-offset-order.ll
+++ llvm/trunk/test/DebugInfo/X86/fragment-offset-order.ll
@@ -0,0 +1,62 @@
+; RUN: llc -dwarf-version=4 -filetype=obj -O0 \
+; RUN:     -mtriple=x86_64-unknown-linux-gnu < %s \
+; RUN:     | llvm-dwarfdump -v - | FileCheck %s
+
+; Verify that the empty DW_OP_piece operations that are created for the
+; optimized-out struct fields `foo' and `baz' are emitted before their
+; succeeding fields' symbol location expressions.
+
+; Test file based on foo.c:
+;
+; struct {
+;   long foo;
+;   void *bar;
+;   long baz;
+;   void *qux;
+; } static var;
+; 
+; void *ptr;
+; 
+; int main() {
+;   if (var.foo == 0)
+;     var.bar = var.qux = ptr;
+;   return 0;
+; }
+;
+; which was built using:
+;
+; clang -O0 -g2 -S -emit-llvm foo.c -o foo.ll
+; opt -S -globalopt foo.ll -o foo.opt.ll
+
+; CHECK: DW_AT_name {{.*}}"var"
+; CHECK: DW_AT_location [DW_FORM_exprloc] (DW_OP_piece 0x8, DW_OP_addr 0x0, DW_OP_piece 0x8, DW_OP_piece 0x8, DW_OP_addr 0x0, DW_OP_piece 0x8)
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at var.1 = internal unnamed_addr global i8* null, align 8, !dbg !0
+ at var.3 = internal unnamed_addr global i8* null, align 8, !dbg !15
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!16, !17}
+!llvm.ident = !{!18}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression(DW_OP_LLVM_fragment, 64, 64))
+!1 = distinct !DIGlobalVariable(name: "var", scope: !2, file: !3, line: 15, type: !7, isLocal: true, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 7.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
+!3 = !DIFile(filename: "foo.c", directory: "/")
+!4 = !{}
+!5 = !{!6}
+!6 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!7 = distinct !DICompositeType(tag: DW_TAG_structure_type, file: !3, line: 10, size: 256, elements: !8)
+!8 = !{!9, !11, !13, !14}
+!9 = !DIDerivedType(tag: DW_TAG_member, name: "foo", scope: !7, file: !3, line: 11, baseType: !10, size: 64)
+!10 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed)
+!11 = !DIDerivedType(tag: DW_TAG_member, name: "bar", scope: !7, file: !3, line: 12, baseType: !12, size: 64, offset: 64)
+!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+!13 = !DIDerivedType(tag: DW_TAG_member, name: "baz", scope: !7, file: !3, line: 13, baseType: !10, size: 64, offset: 128)
+!14 = !DIDerivedType(tag: DW_TAG_member, name: "qux", scope: !7, file: !3, line: 14, baseType: !12, size: 64, offset: 192)
+!15 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression(DW_OP_LLVM_fragment, 192, 64))
+!16 = !{i32 2, !"Dwarf Version", i32 4}
+!17 = !{i32 2, !"Debug Info Version", i32 3}
+!18 = !{!"clang version 7.0.0"}


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D42527.131769.patch
Type: text/x-patch
Size: 3795 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20180129/629e79ff/attachment.bin>