r318456 - Issue -Wempty-body warnings for else blocks

[Hans Wennborg via cfe-commits]

Reverted in r318667.

See coments on the r318556 thread.

On Thu, Nov 16, 2017 at 3:32 PM, Richard Smith via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
> This is kicking up false positives on code that does the following:
>
> #define USED(x) if(x);else
> // ...
> assert(x);
> USED(x);
>
> It's a bit of a weird pattern, but it occurs in some open-source code and
> seems easy enough for us to detect (if the semicolon and the preceding token
> aren't from the same FileID, we shouldn't be diagnosing, because they aren't
> actually adjacent).
>
> On 16 November 2017 at 13:26, Reid Kleckner via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
>>
>> Author: rnk
>> Date: Thu Nov 16 13:26:18 2017
>> New Revision: 318456
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=318456&view=rev
>> Log:
>> Issue -Wempty-body warnings for else blocks
>>
>> This looks like it was just an oversight.
>>
>> Fixes http://llvm.org/pr35319
>>
>> Modified:
>>     cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>     cfe/trunk/lib/Sema/SemaStmt.cpp
>>     cfe/trunk/test/SemaCXX/warn-empty-body.cpp
>>
>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=318456&r1=318455&r2=318456&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Nov 16
>> 13:26:18 2017
>> @@ -8090,6 +8090,8 @@ def err_switch_incomplete_class_type : E
>>
>>  def warn_empty_if_body : Warning<
>>    "if statement has empty body">, InGroup<EmptyBody>;
>> +def warn_empty_else_body : Warning<
>> +  "else clause has empty body">, InGroup<EmptyBody>;
>>  def warn_empty_for_body : Warning<
>>    "for loop has empty body">, InGroup<EmptyBody>;
>>  def warn_empty_range_based_for_body : Warning<
>>
>> Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=318456&r1=318455&r2=318456&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaStmt.cpp Thu Nov 16 13:26:18 2017
>> @@ -527,7 +527,9 @@ Sema::ActOnIfStmt(SourceLocation IfLoc,
>>                         CondExpr->getExprLoc()))
>>      CommaVisitor(*this).Visit(CondExpr);
>>
>> -  if (!elseStmt)
>> +  if (elseStmt)
>> +    DiagnoseEmptyStmtBody(ElseLoc, elseStmt, diag::warn_empty_else_body);
>> +  else
>>      DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), thenStmt,
>>                            diag::warn_empty_if_body);
>>
>>
>> Modified: cfe/trunk/test/SemaCXX/warn-empty-body.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-empty-body.cpp?rev=318456&r1=318455&r2=318456&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/warn-empty-body.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/warn-empty-body.cpp Thu Nov 16 13:26:18 2017
>> @@ -238,6 +238,26 @@ void test6(int x, int y) {
>>    }
>>  }
>>
>> +void test_if_else(int x) {
>> +  if (x); // expected-warning{{if statement has empty body}}
>> expected-note{{separate line}}
>> +
>> +  if (x)
>> +    ; // no-warning
>> +
>> +  if (x)
>> +    ; // no-warning
>> +  else
>> +    ; // no-warning
>> +
>> +  if (x)
>> +    ; // no-warning
>> +  else; // expected-warning{{else clause has empty body}}
>> expected-note{{separate line}}
>> +
>> +  if (x)
>> +    ; // no-warning
>> +  else EMPTY(x); // no-warning
>> +}
>> +
>>  void test_errors(int x) {
>>    if (1)
>>      aa; // expected-error{{use of undeclared identifier}}
>>
>>
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>
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