[llvm] r261168 - DwarfDebug: Don't drop the DIExpression just because a variable is

[Adrian Prantl via llvm-commits]

Author: adrian
Date: Wed Feb 17 16:20:08 2016
New Revision: 261168

URL: http://llvm.org/viewvc/llvm-project?rev=261168&view=rev
Log:
DwarfDebug: Don't drop the DIExpression just because a variable is
described by an immediate.

Found via http://reviews.llvm.org/D16867
Thanks to Paul Robinson for pointing this out.

<rdar://problem/24456528>

Added:
    llvm/trunk/test/DebugInfo/ARM/split-complex.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp?rev=261168&r1=261167&r2=261168&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp Wed Feb 17 16:20:08 2016
@@ -504,9 +504,20 @@ DIE *DwarfCompileUnit::constructVariable
         addVariableAddress(DV, *VariableDie, Location);
       } else if (RegOp.getReg())
         addVariableAddress(DV, *VariableDie, MachineLocation(RegOp.getReg()));
-    } else if (DVInsn->getOperand(0).isImm())
-      addConstantValue(*VariableDie, DVInsn->getOperand(0), DV.getType());
-    else if (DVInsn->getOperand(0).isFPImm())
+    } else if (DVInsn->getOperand(0).isImm()) {
+      // This variable is described by a single constant.
+      // Check whether it has a DIExpression.
+      auto *Expr = DV.getSingleExpression();
+      if (Expr && Expr->getNumElements()) {
+        DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+        DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
+        // If there is an expression, emit raw unsigned bytes.
+        DwarfExpr.AddUnsignedConstant(DVInsn->getOperand(0).getImm());
+        DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end());
+        addBlock(*VariableDie, dwarf::DW_AT_location, Loc);
+      } else
+        addConstantValue(*VariableDie, DVInsn->getOperand(0), DV.getType());
+    } else if (DVInsn->getOperand(0).isFPImm())
       addConstantFPValue(*VariableDie, DVInsn->getOperand(0));
     else if (DVInsn->getOperand(0).isCImm())
       addConstantValue(*VariableDie, DVInsn->getOperand(0).getCImm(),

Added: llvm/trunk/test/DebugInfo/ARM/split-complex.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/ARM/split-complex.ll?rev=261168&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/ARM/split-complex.ll (added)
+++ llvm/trunk/test/DebugInfo/ARM/split-complex.ll Wed Feb 17 16:20:08 2016
@@ -0,0 +1,57 @@
+; RUN: %llc_dwarf -O0 -filetype=obj -o %t.o %s
+; RUN: llvm-dwarfdump -debug-dump=info %t.o | FileCheck %s
+; REQUIRES: object-emission
+target datalayout = "e-m:o-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "thumbv7-apple-unknown-macho"
+
+; generated from (-triple thumbv7-apple-unknown-macho -Os):
+;   void f(_Complex double c) { c = 0; }
+
+; Function Attrs: nounwind readnone
+define arm_aapcscc void @f([2 x i64] %c.coerce) #0 !dbg !4 {
+entry:
+  tail call void @llvm.dbg.declare(metadata { double, double }* undef, metadata !14, metadata !15), !dbg !16
+  ; The target has no native double type.
+  ; SROA split the complex value into two i64 values.
+  ; CHECK: DW_TAG_formal_parameter
+  ; CHECK-NEXT:  DW_AT_location [DW_FORM_block1]	(<0x04> 10 00 93 08 )
+  ;              DW_AT_location       ( constu 0x00000000, piece 0x00000008 )
+  ; CHECK-NEXT:  DW_AT_name {{.*}} "c"
+  tail call void @llvm.dbg.value(metadata i64 0, i64 0, metadata !14, metadata !17), !dbg !16
+  ; Manually removed to disable location list emission:
+  ; tail call void @llvm.dbg.value(metadata i64 0, i64 0, metadata !14, metadata !18), !dbg !16
+  ret void, !dbg !19
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #0
+
+attributes #0 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!9, !10, !11, !12}
+!llvm.ident = !{!13}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 259998) (llvm/trunk 259999)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "<stdin>", directory: "/")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DISubprogram(name: "f", scope: !5, file: !5, line: 1, type: !6, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, variables: !2)
+!5 = !DIFile(filename: "test.c", directory: "/")
+!6 = !DISubroutineType(types: !7)
+!7 = !{null, !8}
+!8 = !DIBasicType(name: "complex", size: 128, align: 64, encoding: DW_ATE_complex_float)
+!9 = !{i32 2, !"Dwarf Version", i32 2}
+!10 = !{i32 2, !"Debug Info Version", i32 3}
+!11 = !{i32 1, !"wchar_size", i32 4}
+!12 = !{i32 1, !"min_enum_size", i32 4}
+!13 = !{!"clang version 3.9.0 (trunk 259998) (llvm/trunk 259999)"}
+!14 = !DILocalVariable(name: "c", arg: 1, scope: !4, file: !5, line: 1, type: !8)
+!15 = !DIExpression()
+!16 = !DILocation(line: 1, column: 24, scope: !4)
+!17 = !DIExpression(DW_OP_bit_piece, 0, 64)
+!18 = !DIExpression(DW_OP_bit_piece, 64, 64)
+!19 = !DILocation(line: 1, column: 36, scope: !4)