r183597 - Debug info: An if condition now creates a lexical scope of its own.

[David Blaikie]

On Fri, Jun 7, 2013 at 5:16 PM, Adrian Prantl <aprantl at apple.com> wrote:
> Author: adrian
> Date: Fri Jun  7 19:16:55 2013
> New Revision: 183597
>
> URL: http://llvm.org/viewvc/llvm-project?rev=183597&view=rev
> Log:
> Debug info: An if condition now creates a lexical scope of its own.
> Two variables with the same name declared in two if conditions in the same
> scope are no longer coalesced into one.

With this (or Eric's) change do we get the right (same as (or
justified if different) GCC) number/placement of scopes/variables for:

if (x)
  a();
else
  b();

if (int x = ...)
  a();
else
  b();

if (int x = ...) {
  int y = ...;
  a();
} else {
  int z = ...;
}

(in theory 'x' should be in-scope across both the if and the else, but
we probably don't bother creating a scope if there's no variable in
that scope - and just create one for the if/else bodies... but not
sure)

>
> rdar://problem/14024005
>
> Added:
>     cfe/trunk/test/CodeGenCXX/debug-info-scope.cpp
> Modified:
>     cfe/trunk/lib/CodeGen/CGStmt.cpp
>     cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp
>
> Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=183597&r1=183596&r2=183597&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGStmt.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGStmt.cpp Fri Jun  7 19:16:55 2013
> @@ -419,6 +419,11 @@ void CodeGenFunction::EmitIfStmt(const I
>    // unequal to 0.  The condition must be a scalar type.
>    RunCleanupsScope ConditionScope(*this);
>
> +  // Also open a debugger-visible lexical scope for the condition.
> +  CGDebugInfo *DI = getDebugInfo();
> +  if (DI)
> +    DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin());
> +
>    if (S.getConditionVariable())
>      EmitAutoVarDecl(*S.getConditionVariable());
>
> @@ -439,6 +444,8 @@ void CodeGenFunction::EmitIfStmt(const I
>          RunCleanupsScope ExecutedScope(*this);
>          EmitStmt(Executed);
>        }
> +      if (DI)
> +        DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
>        return;
>      }
>    }
> @@ -476,6 +483,9 @@ void CodeGenFunction::EmitIfStmt(const I
>      EmitBranch(ContBlock);
>    }
>
> +  if (DI)
> +    DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
> +
>    // Emit the continuation block for code after the if.
>    EmitBlock(ContBlock, true);
>  }
>
> 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=183597&r1=183596&r2=183597&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/debug-info-namespace.cpp Fri Jun  7 19:16:55 2013
> @@ -50,8 +50,9 @@ int func(bool b) {
>  // CHECK: [[M1]] = metadata !{i32 {{[0-9]*}}, metadata [[CTXT]], metadata [[NS]], i32 9} ; [ DW_TAG_imported_module ]
>  // CHECK: [[M2]] = metadata !{i32 {{[0-9]*}}, metadata [[CU]], metadata [[CTXT]], i32 12} ; [ DW_TAG_imported_module ]
>  // CHECK: [[M3]] = metadata !{i32 {{[0-9]*}}, metadata [[CU]], metadata [[CTXT]], i32 13, metadata !"E"} ; [ DW_TAG_imported_module ]
> -// CHECK: [[M4]] = metadata !{i32 {{[0-9]*}}, metadata [[LEX:![0-9]*]], metadata [[NS]], i32 17} ; [ DW_TAG_imported_module ]
> -// CHECK: [[LEX]] = metadata !{i32 {{[0-9]*}}, metadata [[FILE2]], metadata [[FUNC]], i32 16, i32 0, i32 0} ; [ DW_TAG_lexical_block ]
> +// CHECK: [[M4]] = metadata !{i32 {{[0-9]*}}, metadata [[LEX2:![0-9]*]], metadata [[NS]], i32 17} ; [ DW_TAG_imported_module ]
> +// CHECK: [[LEX2]] = metadata !{i32 {{[0-9]*}}, metadata [[FILE2]], metadata [[LEX1:![0-9]+]], i32 16, i32 0, i32 {{.*}}} ; [ DW_TAG_lexical_block ]
> +// CHECK: [[LEX1]] = metadata !{i32 {{[0-9]*}}, metadata [[FILE2]], metadata [[FUNC]], i32 16, i32 0, i32 {{.*}}} ; [ DW_TAG_lexical_block ]
>  // CHECK: [[M5]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[CTXT]], i32 20} ; [ DW_TAG_imported_module ]
>  // CHECK: [[M6]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[FOO:![0-9]*]], i32 21} ; [ DW_TAG_imported_declaration ]
>  // CHECK: [[FOO]] {{.*}} ; [ DW_TAG_structure_type ] [foo] [line 5, size 0, align 0, offset 0] [fwd] [from ]
>
> Added: cfe/trunk/test/CodeGenCXX/debug-info-scope.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/debug-info-scope.cpp?rev=183597&view=auto
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/debug-info-scope.cpp (added)
> +++ cfe/trunk/test/CodeGenCXX/debug-info-scope.cpp Fri Jun  7 19:16:55 2013
> @@ -0,0 +1,32 @@
> +// RUN: %clang_cc1 -g -emit-llvm %s -o -| FileCheck %s
> +//
> +// Two variables with the same name in subsequent if staments need to be in separate scopes.
> +//
> +// rdar://problem/14024005
> +//
> +
> +int printf(const char*, ...);
> +
> +char *return_char (int input)
> +{
> +  if (input%2 == 0)
> +    return "I am even.\n";
> +  else
> +    return "I am odd.\n";
> +}
> +
> +int main2() {
> +// CHECK: [ DW_TAG_auto_variable ] [ptr] [line [[@LINE+2]]]
> +// CHECK metadata !{i32 {{.*}}, metadata !{{.*}}, i32 [[@LINE+1]], {{.*}}} ; [ DW_TAG_lexical_block ]
> +  if (char *ptr = return_char(1)) {
> +    printf ("%s", ptr);
> +  }
> +// CHECK: [ DW_TAG_auto_variable ] [ptr] [line [[@LINE+2]]]
> +// CHECK metadata !{i32 {{.*}}, metadata !{{.*}}, i32 [[@LINE+1]], {{.*}}} ; [ DW_TAG_lexical_block ]
> +  if (char *ptr = return_char(2)) {
> +    printf ("%s", ptr);
> +  }
> +  else printf ("%s", ptr);
> +
> +  return 0;
> +}
>
>
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