[cfe-commits] r156148 - in /cfe/trunk: lib/Sema/SemaStmt.cpp test/SemaCXX/warn-loop-analysis.cpp

[Jordy Rose]

Should static local variables be excepted from this exception? I can contrive a case where it wouldn't be a problem, but in general it's probably just as bad.

> void bad() {
> 	static int x = 5;
> 	for (;x;) { printf("hi"); }
> 	x = 0;
> }
> 
> void okay() {
> 	static int x = 5;
> 	--x;
> 	for (;x;) { printf("hi"); okay(); }
> }
> 
> void badButHardToCatch() {
> 	static int x = 5;
> 	for (;x;) { printf("hi"); badButHardToCatch(); }
> 	--x;
> }

Jordy


On May 3, 2012, at 23:01, Richard Trieu wrote:

> Author: rtrieu
> Date: Thu May  3 22:01:54 2012
> New Revision: 156148
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=156148&view=rev
> Log:
> Skip checking for infinite for-loops if there are global or static variables
> in the conditional.
> 
> Modified:
>    cfe/trunk/lib/Sema/SemaStmt.cpp
>    cfe/trunk/test/SemaCXX/warn-loop-analysis.cpp
> 
> Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=156148&r1=156147&r2=156148&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaStmt.cpp Thu May  3 22:01:54 2012
> @@ -1214,11 +1214,12 @@
>     // No decls found.
>     if (Decls.size() == 0) return;
> 
> -    // Don't warn on volatile decls.
> +    // Don't warn on volatile, static, or global variables.
>     for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(),
>                                                   E = Decls.end();
>          I != E; ++I)
> -      if ((*I)->getType().isVolatileQualified()) return;
> +      if ((*I)->getType().isVolatileQualified() ||
> +          (*I)->hasGlobalStorage()) return;
> 
>     if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
>         DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
> 
> Modified: cfe/trunk/test/SemaCXX/warn-loop-analysis.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-loop-analysis.cpp?rev=156148&r1=156147&r2=156148&view=diff
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/warn-loop-analysis.cpp (original)
> +++ cfe/trunk/test/SemaCXX/warn-loop-analysis.cpp Thu May  3 22:01:54 2012
> @@ -144,3 +144,11 @@
>   for (int a; a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a;);//\
>    // expected-warning {{variable 'a' used in loop condition not modified in loop body}}
> }
> +
> +// Ignore global variables and static variables.
> +int x6;
> +void test6() {
> +  static int y;
> +  for (;x6;);
> +  for (;y;);
> +}
> 
> 
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