[llvm] r239420 - Revert "[DWARF] Fix a few corner cases in expression emission"

David Blaikie dblaikie at gmail.com
Tue Jun 9 11:01:52 PDT 2015


Author: dblaikie
Date: Tue Jun  9 13:01:51 2015
New Revision: 239420

URL: http://llvm.org/viewvc/llvm-project?rev=239420&view=rev
Log:
Revert "[DWARF] Fix a few corner cases in expression emission"

This reverts commit r239380 due to apparently GDB regressions:
http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/22562

Removed:
    llvm/trunk/test/DebugInfo/X86/expressions.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=239420&r1=239419&r2=239420&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Tue Jun  9 13:01:51 2015
@@ -1562,8 +1562,6 @@ void DwarfDebug::emitDebugLoc() {
     Asm->OutStreamer->EmitLabel(List.Label);
     const DwarfCompileUnit *CU = List.CU;
     for (const auto &Entry : DebugLocs.getEntries(List)) {
-       if (Entry.BeginSym == Entry.EndSym)
-        continue;
       // Set up the range. This range is relative to the entry point of the
       // compile unit. This is a hard coded 0 for low_pc when we're emitting
       // ranges, or the DW_AT_low_pc on the compile unit otherwise.

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp?rev=239420&r1=239419&r2=239420&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp Tue Jun  9 13:01:51 2015
@@ -65,11 +65,6 @@ void DwarfExpression::AddShr(unsigned Sh
   EmitOp(dwarf::DW_OP_shr);
 }
 
-void DwarfExpression::AddOpStackValue() {
-  if (DwarfVersion >= 4)
-    EmitOp(dwarf::DW_OP_stack_value);
-}
-
 bool DwarfExpression::AddMachineRegIndirect(unsigned MachineReg, int Offset) {
   if (isFrameRegister(MachineReg)) {
     // If variable offset is based in frame register then use fbreg.
@@ -177,14 +172,16 @@ void DwarfExpression::AddSignedConstant(
   // value, so the producers and consumers started to rely on heuristics
   // to disambiguate the value vs. location status of the expression.
   // See PR21176 for more details.
-  AddOpStackValue();
+  if (DwarfVersion >= 4)
+    EmitOp(dwarf::DW_OP_stack_value);
 }
 
 void DwarfExpression::AddUnsignedConstant(unsigned Value) {
   EmitOp(dwarf::DW_OP_constu);
   EmitUnsigned(Value);
   // cf. comment in DwarfExpression::AddSignedConstant().
-  AddOpStackValue();
+  if (DwarfVersion >= 4)
+    EmitOp(dwarf::DW_OP_stack_value);
 }
 
 static unsigned getOffsetOrZero(unsigned OffsetInBits,
@@ -215,30 +212,15 @@ bool DwarfExpression::AddMachineRegExpre
                getOffsetOrZero(OffsetInBits, PieceOffsetInBits));
   }
   case dwarf::DW_OP_plus: {
+    // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].
     auto N = I.getNext();
-    unsigned Offset = I->getArg(0);
-    // First combine all DW_OP_plus until we hit either a DW_OP_deref or a
-    // DW_OP_bit_piece
-    while (N != E && N->getOp() == dwarf::DW_OP_plus) {
-      Offset += N->getArg(0);
-      ++I;
-      N = I.getNext();
-    }
     if (N != E && N->getOp() == dwarf::DW_OP_deref) {
-      // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].
+      unsigned Offset = I->getArg(0);
       ValidReg = AddMachineRegIndirect(MachineReg, Offset);
       std::advance(I, 2);
-    } else {
-      assert ((N == E) || (N->getOp() == dwarf::DW_OP_bit_piece));
-      if (Offset == 0) {
-        ValidReg = AddMachineRegPiece(MachineReg);
-      } else {
-        ValidReg = AddMachineRegIndirect(MachineReg, Offset);
-        AddOpStackValue();
-      }
-      ++I;
-    }
-    break;
+      break;
+    } else
+      ValidReg = AddMachineRegPiece(MachineReg);
   }
   case dwarf::DW_OP_deref: {
       // [DW_OP_reg,DW_OP_deref] --> [DW_OP_breg].
@@ -255,7 +237,6 @@ bool DwarfExpression::AddMachineRegExpre
 
   // Emit remaining elements of the expression.
   AddExpression(I, E, PieceOffsetInBits);
-
   return true;
 }
 

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h?rev=239420&r1=239419&r2=239420&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h Tue Jun  9 13:01:51 2015
@@ -83,9 +83,6 @@ public:
   bool AddMachineRegPiece(unsigned MachineReg, unsigned PieceSizeInBits = 0,
                           unsigned PieceOffsetInBits = 0);
 
-  /// Emit a DW_OP_stack_value
-  void AddOpStackValue();
-
   /// Emit a signed constant.
   void AddSignedConstant(int Value);
   /// Emit an unsigned constant.

Removed: llvm/trunk/test/DebugInfo/X86/expressions.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/expressions.ll?rev=239419&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/expressions.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/expressions.ll (removed)
@@ -1,110 +0,0 @@
-; REQUIRES: object-emission
-; RUN: llc -mtriple x86_64-apple-darwin14.0.0-elf -filetype=obj %s -o %t
-; RUN: llc -mtriple x86_64-apple-darwin14.0.0-elf -O0 -filetype=obj %s -o %t0
-; RUN: llvm-dwarfdump -debug-dump=loc %t | FileCheck %s
-; RUN: llvm-dwarfdump -debug-dump=loc %t0 | FileCheck -check-prefix CHECK-O0 %s
-
-; CHECK: 0x00000000: Beginning address offset: 0x0000000000000000
-; CHECK:                Ending address offset: 0x[[END:[0-9a-f]+]]
-; CHECK:                 Location description:
-; CHECK-NOT:                                   75 00 55
-; CHECK-SAME:                                  55
-; CHECK: 0x00000023: Beginning address offset: 0x0000000000000000
-; CHECK:                Ending address offset: 0x{{.*}}[[END]]
-; CHECK:                 Location description: 75 08 9f
-; CHECK: 0x00000048: Beginning address offset: 0x0000000000000000
-; CHECK:                Ending address offset: 0x{{.*}}[[END]]
-; CHECK:                 Location description: 75 10 9f
-; CHECK: 0x0000006d: Beginning address offset: 0x0000000000000000
-; CHECK:                Ending address offset: 0x{{.*}}[[END]]
-; CHECK:                 Location description: 75 18
-
-
-; CHECK-O0: 0x00000000: Beginning address offset: 0x0000000000000000
-; CHECK-O0:                Ending address offset: 0x000000000000001b
-; CHECK-O0:                 Location description: 55
-; CHECK-O0:             Beginning address offset: 0x000000000000001b
-; CHECK-O0:                Ending address offset: 0x0000000000000024
-; CHECK-O0:                 Location description: 54
-; CHECK-O0:             Beginning address offset: 0x0000000000000024
-; CHECK-O0:                Ending address offset: 0x0000000000000025
-; CHECK-O0:                 Location description: 77 78 23 00
-; CHECK-O0: 0x0000004c: Beginning address offset: 0x0000000000000000
-; CHECK-O0:                Ending address offset: 0x000000000000001b
-; CHECK-O0:                 Location description: 75 08 9f
-; CHECK-O0:             Beginning address offset: 0x000000000000001b
-; CHECK-O0:                Ending address offset: 0x0000000000000024
-; CHECK-O0:                 Location description: 74 08 9f
-; CHECK-O0:             Beginning address offset: 0x0000000000000024
-; CHECK-O0:                Ending address offset: 0x0000000000000025
-; CHECK-O0:                 Location description: 77 78 23 08
-; CHECK-O0: 0x0000009c: Beginning address offset: 0x0000000000000000
-; CHECK-O0:                Ending address offset: 0x000000000000001b
-; CHECK-O0:                 Location description: 75 10 9f
-; CHECK-O0:             Beginning address offset: 0x000000000000001b
-; CHECK-O0:                Ending address offset: 0x0000000000000024
-; CHECK-O0:                 Location description: 74 10 9f
-; CHECK-O0:             Beginning address offset: 0x0000000000000024
-; CHECK-O0:                Ending address offset: 0x0000000000000025
-; CHECK-O0:                 Location description: 77 78 23 08 23 08
-; CHECK-O0: 0x000000ee: Beginning address offset: 0x0000000000000000
-; CHECK-O0:                Ending address offset: 0x000000000000001b
-; CHECK-O0:                 Location description: 75 18
-; CHECK-O0:             Beginning address offset: 0x000000000000001b
-; CHECK-O0:                Ending address offset: 0x0000000000000024
-; CHECK-O0:                 Location description: 74 18
-; CHECK-O0:             Beginning address offset: 0x0000000000000024
-; CHECK-O0:                Ending address offset: 0x0000000000000025
-; CHECK-O0:                 Location description: 77 78 23 10 23 08 06
-
-declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #0
-
-define float @foo(float* %args, float *%args2)
-{
-    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !11, metadata !12), !dbg !19
-    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !13, metadata !14), !dbg !19
-    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !15, metadata !16), !dbg !19
-    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !17, metadata !18), !dbg !19
-    %a = load float, float* %args, !dbg !19
-    %bptr = getelementptr float, float* %args, i32 1, !dbg !19
-    %b = load float, float* %bptr, !dbg !19
-    %cptr = getelementptr float, float* %args, i32 2, !dbg !19
-    %c = load float, float* %cptr, !dbg !19
-    %dptr = getelementptr float, float* %args, i32 3, !dbg !19
-    %d = load float, float* %dptr, !dbg !19
-    %ret1 = fadd float %a, %b, !dbg !19
-    %ret2 = fadd float %c, %d, !dbg !19
-    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !11, metadata !12), !dbg !19
-    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !13, metadata !14), !dbg !19
-    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !15, metadata !16), !dbg !19
-    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !17, metadata !18), !dbg !19
-    %ret  = fsub float %ret1, %ret2, !dbg !19
-    ret float %ret, !dbg !19
-}
-
-attributes #0 = { nounwind readnone }
-
-!llvm.module.flags = !{!0, !1}
-!llvm.dbg.cu = !{!2}
-
-!0 = !{i32 2, !"Dwarf Version", i32 4}
-!1 = !{i32 1, !"Debug Info Version", i32 3}
-
-!2 = !DICompileUnit(language: DW_LANG_C89, file: !3, producer: "byHand", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !4, retainedTypes: !4, subprograms: !5, globals: !4, imports: !4)
-!3 = !DIFile(filename: "expressions", directory: ".")
-!4 = !{}
-!5 = !{!6}
-!6 = !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !3, type: !7, isLocal: false, isDefinition: true, isOptimized: true, function: float (float*, float*)* @foo, variables: !4)
-!7 = !DISubroutineType(types: !8)
-!8 = !{!10, !10}
-!9 = !DIBasicType(name: "float", size: 4, align: 4, encoding: DW_ATE_float)
-!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64, align: 64)
-!11 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "a", arg: 1, scope: !6, file: !3, line: 1, type: !10)
-!12 = !DIExpression(DW_OP_plus, 0)
-!13 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "b", arg: 2, scope: !6, file: !3, line: 1, type: !10)
-!14 = !DIExpression(DW_OP_plus, 8)
-!15 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "c", arg: 3, scope: !6, file: !3, line: 1, type: !10)
-!16 = !DIExpression(DW_OP_plus, 8, DW_OP_plus, 8)
-!17 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "d", arg: 4, scope: !6, file: !3, line: 1, type: !9)
-!18 = !DIExpression(DW_OP_plus, 16, DW_OP_plus, 8, DW_OP_deref)
-!19 = !DILocation(line: 1, scope: !6)





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