[PATCH] Fix the argument index error of __builtin___memccpy_chk

[Steven Wu]

Thanks Eric for review. 
Commit to r218367.

> On Sep 23, 2014, at 5:06 PM, Eric Christopher <echristo at gmail.com> wrote:
> 
> OK.
> 
> -eric
> 
> On Tue, Sep 23, 2014 at 4:51 PM, Steven Wu <stevenwu at apple.com> wrote:
>> Add the testcase. The assertion failure only happens when size_t is not the
>> same as int, so I add the test to builtin-object-size.c.
>> I can also add it to builtins.c as an alternative, it won’t assertion failed
>> but it will give the wrong diagnostics. Let me know if the other way is
>> better.
>> 
>> New patch:
>> --- a/lib/Sema/SemaChecking.cpp
>> +++ b/lib/Sema/SemaChecking.cpp
>> @@ -365,7 +365,6 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl,
>> unsigned BuiltinID,
>>   // check secure string manipulation functions where overflows
>>   // are detectable at compile time
>>   case Builtin::BI__builtin___memcpy_chk:
>> -  case Builtin::BI__builtin___memccpy_chk:
>>   case Builtin::BI__builtin___memmove_chk:
>>   case Builtin::BI__builtin___memset_chk:
>>   case Builtin::BI__builtin___strlcat_chk:
>> @@ -375,6 +374,9 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl,
>> unsigned BuiltinID,
>>   case Builtin::BI__builtin___stpncpy_chk:
>>     SemaBuiltinMemChkCall(*this, FDecl, TheCall, 2, 3);
>>     break;
>> +  case Builtin::BI__builtin___memccpy_chk:
>> +    SemaBuiltinMemChkCall(*this, FDecl, TheCall, 3, 4);
>> +    break;
>>   case Builtin::BI__builtin___snprintf_chk:
>>   case Builtin::BI__builtin___vsnprintf_chk:
>>     SemaBuiltinMemChkCall(*this, FDecl, TheCall, 1, 3);
>> diff --git a/test/Sema/builtin-object-size.c
>> b/test/Sema/builtin-object-size.c
>> index e4b6560..b1bda06 100644
>> --- a/test/Sema/builtin-object-size.c
>> +++ b/test/Sema/builtin-object-size.c
>> @@ -43,3 +43,12 @@ void f5(void)
>>   memcpy((char *)NULL + 0x10000, buf, 0x10);
>>   memcpy1((char *)NULL + 0x10000, buf, 0x10); // expected-error {{argument
>> should be a value from 0 to 3}}
>> }
>> +
>> +// rdar://18431336
>> +void f6(void)
>> +{
>> +  char b[5];
>> +  char buf[10];
>> +  __builtin___memccpy_chk (buf, b, '\0', sizeof(b), __builtin_object_size
>> (buf, 0));
>> +  __builtin___memccpy_chk (b, buf, '\0', sizeof(buf), __builtin_object_size
>> (b, 0));  // expected-warning {{'__builtin___memccpy_chk' will always
>> overflow destination buffer}}
>> +}
>> 
>> On Sep 23, 2014, at 4:12 PM, jahanian <fjahanian at apple.com> wrote:
>> 
>> Ok. But please provide a test case. See builtin-object-size.c for some
>> samples.
>> 
>> - Fariborz
>> 
>> 
>> On Sep 23, 2014, at 4:03 PM, Steven Wu <stevenwu at apple.com> wrote:
>> 
>> Fix an assertion failure in CheckBuiltinFunctionCall.
>> memccpy_chk should have source and dest size at arg 3 and 4.
>> 
>> ---
>> lib/Sema/SemaChecking.cpp | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>> 
>> diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
>> index 7462869..5ea862c 100644
>> --- a/lib/Sema/SemaChecking.cpp
>> +++ b/lib/Sema/SemaChecking.cpp
>> @@ -365,7 +365,6 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl,
>> unsigned BuiltinID,
>>  // check secure string manipulation functions where overflows
>>  // are detectable at compile time
>>  case Builtin::BI__builtin___memcpy_chk:
>> -  case Builtin::BI__builtin___memccpy_chk:
>>  case Builtin::BI__builtin___memmove_chk:
>>  case Builtin::BI__builtin___memset_chk:
>>  case Builtin::BI__builtin___strlcat_chk:
>> @@ -375,6 +374,9 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl,
>> unsigned BuiltinID,
>>  case Builtin::BI__builtin___stpncpy_chk:
>>    SemaBuiltinMemChkCall(*this, FDecl, TheCall, 2, 3);
>>    break;
>> +  case Builtin::BI__builtin___memccpy_chk:
>> +    SemaBuiltinMemChkCall(*this, FDecl, TheCall, 3, 4);
>> +    break;
>>  case Builtin::BI__builtin___snprintf_chk:
>>  case Builtin::BI__builtin___vsnprintf_chk:
>>    SemaBuiltinMemChkCall(*this, FDecl, TheCall, 1, 3);
>> 
>> <memccpy.patch>
>> 
>>