[cfe-commits] r157204 - in /cfe/trunk: lib/StaticAnalyzer/Core/ObjCMessage.cpp test/Analysis/PR12905.c

[Benjamin Kramer]

On 21.05.2012, at 22:04, Anna Zaks wrote:

> Benjamin,
> 
> The issue is that the size of the string is 1, correct? Can we just check the size and return if it's less than 2 and proceed with the existing checks afterwards? This function is called a lot.

LLVM knows how to generate great optimized code for startswith, it becomes a check that the length is >=2 and two unaligned loads + compares. It's far more readable and I doubt that it's slower than the old buggy code.

> Do you have a test case?

Yes, and a reduced version was committed along with this fix.

- Ben

> 
> Thanks,
> Anna.
> On May 21, 2012, at 12:40 PM, Benjamin Kramer wrote:
> 
>> Author: d0k
>> Date: Mon May 21 14:40:38 2012
>> New Revision: 157204
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=157204&view=rev
>> Log:
>> Analyzer: Fix PR12905, a crash when encountering a call to a function named "C".
>> 
>> While there clean up indentation.
>> 
>> Added:
>>   cfe/trunk/test/Analysis/PR12905.c
>> Modified:
>>   cfe/trunk/lib/StaticAnalyzer/Core/ObjCMessage.cpp
>> 
>> Modified: cfe/trunk/lib/StaticAnalyzer/Core/ObjCMessage.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/ObjCMessage.cpp?rev=157204&r1=157203&r2=157204&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/StaticAnalyzer/Core/ObjCMessage.cpp (original)
>> +++ cfe/trunk/lib/StaticAnalyzer/Core/ObjCMessage.cpp Mon May 21 14:40:38 2012
>> @@ -161,16 +161,15 @@
>> }
>> 
>> bool CallOrObjCMessage::isCFCGAllowingEscape(StringRef FName) {
>> -  if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G'))
>> -         if (StrInStrNoCase(FName, "InsertValue") != StringRef::npos||
>> -             StrInStrNoCase(FName, "AddValue") != StringRef::npos ||
>> -             StrInStrNoCase(FName, "SetValue") != StringRef::npos ||
>> -             StrInStrNoCase(FName, "WithData") != StringRef::npos ||
>> -             StrInStrNoCase(FName, "AppendValue") != StringRef::npos||
>> -             StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) {
>> -       return true;
>> -     }
>> -  return false;
>> +  if (!FName.startswith("CF") && !FName.startswith("CG"))
>> +    return false;
>> +
>> +  return StrInStrNoCase(FName, "InsertValue")  != StringRef::npos ||
>> +         StrInStrNoCase(FName, "AddValue")     != StringRef::npos ||
>> +         StrInStrNoCase(FName, "SetValue")     != StringRef::npos ||
>> +         StrInStrNoCase(FName, "WithData")     != StringRef::npos ||
>> +         StrInStrNoCase(FName, "AppendValue")  != StringRef::npos ||
>> +         StrInStrNoCase(FName, "SetAttribute") != StringRef::npos;
>> }
>> 
>> 
>> 
>> Added: cfe/trunk/test/Analysis/PR12905.c
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/PR12905.c?rev=157204&view=auto
>> ==============================================================================
>> --- cfe/trunk/test/Analysis/PR12905.c (added)
>> +++ cfe/trunk/test/Analysis/PR12905.c Mon May 21 14:40:38 2012
>> @@ -0,0 +1,8 @@
>> +// RUN: %clang_cc1 -analyze -analyzer-checker=core %s
>> +// PR12905
>> +
>> +void C(void);
>> +
>> +void t(void) {
>> +  C();
>> +}
>> 
>> 
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