r189649 - Fixing a bug where debug info for a local variable gets emitted at file scope.

David Blaikie dblaikie at gmail.com
Thu Aug 29 23:36:07 PDT 2013


On Thu, Aug 29, 2013 at 10:37 PM, Yunzhong Gao
<Yunzhong_Gao at playstation.sony.com> wrote:
> Author: ygao
> Date: Fri Aug 30 00:37:02 2013
> New Revision: 189649
>
> URL: http://llvm.org/viewvc/llvm-project?rev=189649&view=rev
> Log:
> Fixing a bug where debug info for a local variable gets emitted at file scope.

Seems this fixed a few XFAILs in the GDB 7.5 test suite (
http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/8340/steps/gdb-75-check/logs/gdb.cp__namespace.exp
) would you mind fixing those? (remove the "if clang setup_xfail"
lines from http://llvm.org/viewvc/llvm-project/clang-tests-external/trunk/gdb/7.5/gdb/testsuite/gdb.cp/namespace.exp
)

Otherwise I can do it.

>
> The patch was discussed in Phabricator. See:
> http://llvm-reviews.chandlerc.com/D1281
>
>
> Added:
>     cfe/trunk/test/CodeGen/debug-info-line5.cpp
>     cfe/trunk/test/CodeGen/debug-info-line5.h
> Modified:
>     cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
>     cfe/trunk/lib/CodeGen/CGDebugInfo.h
>     cfe/trunk/lib/CodeGen/CGExpr.cpp
>     cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
>     cfe/trunk/lib/CodeGen/CodeGenFunction.h
>     cfe/trunk/test/CodeGen/debug-info-scope.c
>     cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp
>
> Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.cpp?rev=189649&r1=189648&r2=189649&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp Fri Aug 30 00:37:02 2013
> @@ -3142,14 +3142,31 @@ CGDebugInfo::getOrCreateStaticDataMember
>  }
>
>  /// EmitGlobalVariable - Emit information about a global variable.
> -void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
> +/// \param VarOrInit either the global variable itself or the initializer
> +/// \param D the global declaration
> +void CGDebugInfo::EmitGlobalVariable(llvm::Value *VarOrInit,
>                                       const VarDecl *D) {
>    assert(DebugKind >= CodeGenOptions::LimitedDebugInfo);
>    // Create global variable debug descriptor.
>    llvm::DIFile Unit = getOrCreateFile(D->getLocation());
>    unsigned LineNo = getLineNumber(D->getLocation());
> +  StringRef DeclName = D->getName();
> +  StringRef LinkageName;
> +  bool IsLocalToUnit = true;
>
> -  setLocation(D->getLocation());
> +  // For deferred global variables, the current source location is usually
> +  // where they are being referenced. Do not change the current source location
> +  // to the place where they are declared, lest we get a bogus line table.
> +  // FIXME: maybe we do not need to set the source location here at all.
> +  if (llvm::GlobalVariable *Var = dyn_cast<llvm::GlobalVariable>(VarOrInit)) {
> +    setLocation(D->getLocation());
> +    IsLocalToUnit = Var->hasInternalLinkage();
> +    if (D->getDeclContext() && !isa<FunctionDecl>(D->getDeclContext())
> +        && !isa<ObjCMethodDecl>(D->getDeclContext()))
> +      LinkageName = Var->getName();
> +    if (LinkageName == DeclName)
> +      LinkageName = StringRef();
> +  }
>
>    QualType T = D->getType();
>    if (T->isIncompleteArrayType()) {
> @@ -3161,18 +3178,11 @@ void CGDebugInfo::EmitGlobalVariable(llv
>      T = CGM.getContext().getConstantArrayType(ET, ConstVal,
>                                                ArrayType::Normal, 0);
>    }
> -  StringRef DeclName = D->getName();
> -  StringRef LinkageName;
> -  if (D->getDeclContext() && !isa<FunctionDecl>(D->getDeclContext())
> -      && !isa<ObjCMethodDecl>(D->getDeclContext()))
> -    LinkageName = Var->getName();
> -  if (LinkageName == DeclName)
> -    LinkageName = StringRef();
>    llvm::DIDescriptor DContext =
>      getContextDescriptor(dyn_cast<Decl>(D->getDeclContext()));
>    llvm::DIGlobalVariable GV = DBuilder.createStaticVariable(
>        DContext, DeclName, LinkageName, Unit, LineNo, getOrCreateType(T, Unit),
> -      Var->hasInternalLinkage(), Var,
> +      IsLocalToUnit, VarOrInit,
>        getOrCreateStaticDataMemberDeclarationOrNull(D));
>    DeclCache.insert(std::make_pair(D->getCanonicalDecl(), llvm::WeakVH(GV)));
>  }
> @@ -3203,26 +3213,16 @@ void CGDebugInfo::EmitGlobalVariable(llv
>                                  Var->hasInternalLinkage(), Var);
>  }
>
> -/// EmitGlobalVariable - Emit global variable's debug info.
> -void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD,
> -                                     llvm::Constant *Init) {
> +/// EmitEnumConstant - Emit debug info for an enumerator constant
> +void CGDebugInfo::EmitEnumConstant(const EnumConstantDecl *ECD)
> +{
>    assert(DebugKind >= CodeGenOptions::LimitedDebugInfo);
> -  // Create the descriptor for the variable.
> -  llvm::DIFile Unit = getOrCreateFile(VD->getLocation());
> -  StringRef Name = VD->getName();
> -  llvm::DIType Ty = getOrCreateType(VD->getType(), Unit);
> -  if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(VD)) {
> -    const EnumDecl *ED = cast<EnumDecl>(ECD->getDeclContext());
> -    assert(isa<EnumType>(ED->getTypeForDecl()) && "Enum without EnumType?");
> -    Ty = getOrCreateType(QualType(ED->getTypeForDecl(), 0), Unit);
> -  }
> -  // Do not use DIGlobalVariable for enums.
> -  if (Ty.getTag() == llvm::dwarf::DW_TAG_enumeration_type)
> -    return;
> -  llvm::DIGlobalVariable GV = DBuilder.createStaticVariable(
> -      Unit, Name, Name, Unit, getLineNumber(VD->getLocation()), Ty, true, Init,
> -      getOrCreateStaticDataMemberDeclarationOrNull(cast<VarDecl>(VD)));
> -  DeclCache.insert(std::make_pair(VD->getCanonicalDecl(), llvm::WeakVH(GV)));
> +  llvm::DIFile Unit = getOrCreateFile(ECD->getLocation());
> +  llvm::DIType Ty = getOrCreateType(ECD->getType(), Unit);
> +
> +  const EnumDecl *ED = cast<EnumDecl>(ECD->getDeclContext());
> +  assert(isa<EnumType>(ED->getTypeForDecl()) && "Enum without EnumType?");
> +  Ty = getOrCreateType(QualType(ED->getTypeForDecl(), 0), Unit);
>  }
>
>  llvm::DIScope CGDebugInfo::getCurrentContextDescriptor(const Decl *D) {
>
> Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.h?rev=189649&r1=189648&r2=189649&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGDebugInfo.h (original)
> +++ cfe/trunk/lib/CodeGen/CGDebugInfo.h Fri Aug 30 00:37:02 2013
> @@ -264,13 +264,13 @@ public:
>                                              CGBuilderTy &Builder);
>
>    /// EmitGlobalVariable - Emit information about a global variable.
> -  void EmitGlobalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
> +  void EmitGlobalVariable(llvm::Value *VarOrInit, const VarDecl *Decl);
>
>    /// EmitGlobalVariable - Emit information about an objective-c interface.
>    void EmitGlobalVariable(llvm::GlobalVariable *GV, ObjCInterfaceDecl *Decl);
>
> -  /// EmitGlobalVariable - Emit global variable's debug info.
> -  void EmitGlobalVariable(const ValueDecl *VD, llvm::Constant *Init);
> +  /// EmitEnumConstant - Emit information about an enumerator constant
> +  void EmitEnumConstant(const EnumConstantDecl *ECD);
>
>    /// \brief - Emit C++ using directive.
>    void EmitUsingDirective(const UsingDirectiveDecl &UD);
>
> Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=189649&r1=189648&r2=189649&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExpr.cpp Fri Aug 30 00:37:02 2013
> @@ -967,15 +967,9 @@ CodeGenFunction::tryEmitAsConstant(DeclR
>    // Emit as a constant.
>    llvm::Constant *C = CGM.EmitConstantValue(result.Val, resultType, this);
>
> -  // Make sure we emit a debug reference to the global variable.
> -  // This should probably fire even for
> -  if (isa<VarDecl>(value)) {
> -    if (!getContext().DeclMustBeEmitted(cast<VarDecl>(value)))
> -      EmitDeclRefExprDbgValue(refExpr, C);
> -  } else {
> -    assert(isa<EnumConstantDecl>(value));
> -    EmitDeclRefExprDbgValue(refExpr, C);
> -  }
> +  // Make sure we emit a debug reference to the global variable or
> +  // enumerator constant.
> +  EmitValueDeclDbgValue(value, C);
>
>    // If we emitted a reference constant, we need to dereference that.
>    if (resultIsReference)
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=189649&r1=189648&r2=189649&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Fri Aug 30 00:37:02 2013
> @@ -1376,12 +1376,27 @@ llvm::Value* CodeGenFunction::EmitVAList
>    return EmitLValue(E).getAddress();
>  }
>
> -void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E,
> -                                              llvm::Constant *Init) {
> +void CodeGenFunction::EmitValueDeclDbgValue(const ValueDecl *Val,
> +                                            llvm::Constant *Init) {
>    assert (Init && "Invalid DeclRefExpr initializer!");
> -  if (CGDebugInfo *Dbg = getDebugInfo())
> -    if (CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo)
> -      Dbg->EmitGlobalVariable(E->getDecl(), Init);
> +  CGDebugInfo *Dbg = getDebugInfo();
> +  if (!Dbg ||
> +      CGM.getCodeGenOpts().getDebugInfo() < CodeGenOptions::LimitedDebugInfo)
> +    return;
> +
> +  // Make sure we emit a debug reference to the global variable.
> +  if (const VarDecl *VD = dyn_cast<VarDecl>(Val)) {
> +    // Do not duplicate DIE entry for local variables; they are not deferred
> +    // like global variables are.
> +    if (VD->isFileVarDecl() && !getLangOpts().EmitAllDecls &&
> +        !getContext().DeclMustBeEmitted(Val))
> +      Dbg->EmitGlobalVariable(Init, VD);
> +
> +  // Make sure we emit a debug reference to an enumerator constant.
> +  } else {
> +    assert(isa<EnumConstantDecl>(Val));
> +    Dbg->EmitEnumConstant(dyn_cast<EnumConstantDecl>(Val));
> +  }
>  }
>
>  CodeGenFunction::PeepholeProtection
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=189649&r1=189648&r2=189649&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Fri Aug 30 00:37:02 2013
> @@ -2047,7 +2047,8 @@ public:
>    LValue EmitStmtExprLValue(const StmtExpr *E);
>    LValue EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E);
>    LValue EmitObjCSelectorLValue(const ObjCSelectorExpr *E);
> -  void   EmitDeclRefExprDbgValue(const DeclRefExpr *E, llvm::Constant *Init);
> +  void   EmitValueDeclDbgValue(const ValueDecl *Val, llvm::Constant *Init);
> +
>
>    //===--------------------------------------------------------------------===//
>    //                         Scalar Expression Emission
>
> Added: cfe/trunk/test/CodeGen/debug-info-line5.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/debug-info-line5.cpp?rev=189649&view=auto
> ==============================================================================
> --- cfe/trunk/test/CodeGen/debug-info-line5.cpp (added)
> +++ cfe/trunk/test/CodeGen/debug-info-line5.cpp Fri Aug 30 00:37:02 2013
> @@ -0,0 +1,18 @@
> +// RUN: %clang %s -g -gcolumn-info -S -emit-llvm -o - | FileCheck %s
> +// Line table entries should reference this cpp file, not the header
> +
> +#include "debug-info-line5.h"
> +
> +int result;
> +int foo(unsigned);
> +
> +int main()
> +{
> +  while ( 1 )
> +  {
> +    result = foo(Marker);
> +  }
> +  return result;
> +}
> +
> +// CHECK: !{{[0-9]*}} = metadata !{i32 {{[0-9]*}}, i32 {{[0-9]*}}, null, metadata !"Marker", {{.*}} ; [ DW_TAG_variable ] [Marker]
>
> Added: cfe/trunk/test/CodeGen/debug-info-line5.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/debug-info-line5.h?rev=189649&view=auto
> ==============================================================================
> --- cfe/trunk/test/CodeGen/debug-info-line5.h (added)
> +++ cfe/trunk/test/CodeGen/debug-info-line5.h Fri Aug 30 00:37:02 2013
> @@ -0,0 +1,2 @@
> +// Declaration of "Marker"
> +const unsigned Marker = 0xFF999999;
>
> Modified: cfe/trunk/test/CodeGen/debug-info-scope.c
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/debug-info-scope.c?rev=189649&r1=189648&r2=189649&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGen/debug-info-scope.c (original)
> +++ cfe/trunk/test/CodeGen/debug-info-scope.c Fri Aug 30 00:37:02 2013
> @@ -1,7 +1,16 @@
>  // RUN: %clang_cc1 -g -emit-llvm < %s | FileCheck %s
> +
> +// Make sure that the debug info of the local variable d does not shadow
> +// the global variable d
> +// CHECK: [ DW_TAG_variable ] [d] [line 6] [def]
> +const int d = 100;
> +
>  // Two variables with same name in separate scope.
>  // Radar 8330217.
>  int main() {
> +// CHECK-NOT: [ DW_TAG_variable ] [d] [line 13]
> +// CHECK: [ DW_TAG_auto_variable ] [d] [line 13]
> +       const int d = 4;
>         int j = 0;
>         int k = 0;
>  // CHECK: DW_TAG_auto_variable ] [i]
> @@ -12,5 +21,5 @@ int main() {
>  // CHECK-NEXT: DW_TAG_lexical_block
>         for (int i = 0; i < 10; i++)
>                 k++;
> -       return 0;
> +       return d; // make a reference to d so that its debug info gets included
>  }
>
> Modified: cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp?rev=189649&r1=189648&r2=189649&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp Fri Aug 30 00:37:02 2013
> @@ -39,6 +39,16 @@ int func(bool b) {
>  // This should work even if 'i' and 'func' were declarations & not definitions,
>  // but it doesn't yet.
>
> +namespace C
> +{
> + const int j = 32;
> +}
> +
> +int func2()
> +{
> + return C::j;
> +}
> +
>  // CHECK: [[CU:![0-9]*]] = {{.*}}[[MODULES:![0-9]*]], metadata !""} ; [ DW_TAG_compile_unit ]
>  // CHECK: [[FILE:![0-9]*]] {{.*}}debug-info-namespace.cpp"
>  // CHECK: [[FOO:![0-9]*]] {{.*}} ; [ DW_TAG_structure_type ] [foo] [line 5, size 0, align 0, offset 0] [decl] [from ]
> @@ -50,6 +60,8 @@ int func(bool b) {
>  // CHECK: [[FUNC:![0-9]*]] {{.*}} ; [ DW_TAG_subprogram ] {{.*}} [def] [func]
>  // CHECK: [[FILE2]]} ; [ DW_TAG_file_type ] [{{.*}}foo.cpp]
>  // CHECK: [[I:![0-9]*]] = {{.*}}, metadata [[NS]], metadata !"i", {{.*}} ; [ DW_TAG_variable ] [i]
> +// CHECK: [[VAR:![0-9]*]] = {{.*}}, metadata [[SPACE:![0-9]*]], metadata !"j", {{.*}} ; [ DW_TAG_variable ] [j]
> +// CHECK: [[SPACE]] = {{.*}}, metadata !"C", {{.*}} ; [ DW_TAG_namespace ] [C]
>  // CHECK: [[MODULES]] = metadata !{metadata [[M1:![0-9]*]], metadata [[M2:![0-9]*]], metadata [[M3:![0-9]*]], metadata [[M4:![0-9]*]], metadata [[M5:![0-9]*]], metadata [[M6:![0-9]*]], metadata [[M7:![0-9]*]], metadata [[M8:![0-9]*]], metadata [[M9:![0-9]*]], metadata [[M10:![0-9]*]], metadata [[M11:![0-9]*]], metadata [[M12:![0-9]*]]}
>  // CHECK: [[M1]] = metadata !{i32 {{[0-9]*}}, metadata [[CTXT]], metadata [[NS]], i32 11} ; [ DW_TAG_imported_module ]
>  // CHECK: [[M2]] = metadata !{i32 {{[0-9]*}}, metadata [[CU]], metadata [[CTXT]], i32 {{[0-9]*}}} ; [ DW_TAG_imported_module ]
>
>
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