r183597 - Debug info: An if condition now creates a lexical scope of its own.
Adrian Prantl
aprantl at apple.com
Mon Jun 10 15:56:11 PDT 2013
(CC’ing John because he understands the intricacies of LexicalScope better than I do)
On the first glimpse LexicalScope appears to be a subclass of RunCleanupsScope that additionally emits a (DebugInfo-)LexicalScope. But looking at the destructors it appears that they have slightly different semantics: ~LexicalScope runs ForceCleanup and ~RunCleanupsScope apparently doesn’t.
I’m wary that switching to Lexicalscope in CodeGenFunction::EmitIfStmt() might lead to tricky ARC or EH-related problems because of that.
Does anyone have an opinion on that?
-- adrian
On Jun 10, 2013, at 10:47 AM, Eric Christopher <echristo at gmail.com> wrote:
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> I think you can just use a LexicalScope here instead of the patch
> you've got. I.e. the attached patch passes all of the tests you added
> - I just did the quick manual replacement without thinking about the
> else or then blocks, but figured you might want to run this on your
> original test?
>
> -eric
>
>
>
> 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.
>>
>> 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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