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Fixed #4906 (False positive: void * calculation (cast))

This commit is contained in:
Lucas Manuel Rodriguez 2013-07-10 06:40:09 +02:00 committed by Daniel Marjamäki
parent 4106972fdc
commit 040c1e3a13
3 changed files with 35 additions and 5 deletions
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9
lib/checksizeof.cpp
View File

@ -295,7 +295,10 @@ void CheckSizeof::sizeofVoid()
int index = (tok->isName()) ? 0 : 1; int index = (tok->isName()) ? 0 : 1;
const Variable* var = tok->tokAt(index)->variable(); const Variable* var = tok->tokAt(index)->variable();
if (var && Token::Match(var->typeStartToken(), "void *")) { if (var && Token::Match(var->typeStartToken(), "void *")) {
arithOperationsOnVoidPointerError(tok, tok->tokAt(index)->str()); if (Token::Match(tok->previous(), ") %var% +|-") && // Check for cast on operations with +|-
!Token::Match(tok->previous()->link(), "( const| void *"))
continue;
arithOperationsOnVoidPointerError(tok, tok->strAt(index), var->typeStartToken()->stringifyList(var->typeEndToken()->next()));
} }
} }
} }
@ -315,9 +318,9 @@ void CheckSizeof::sizeofDereferencedVoidPointerError(const Token *tok, const std
reportError(tok, Severity::portability, "sizeofDereferencedVoidPointer", message + "\n" + verbose); reportError(tok, Severity::portability, "sizeofDereferencedVoidPointer", message + "\n" + verbose);
} }
void CheckSizeof::arithOperationsOnVoidPointerError(const Token* tok, const std::string &varname) void CheckSizeof::arithOperationsOnVoidPointerError(const Token* tok, const std::string &varname, const std::string &vartype)
{ {
const std::string message = "'" + varname + "' is of type 'void *'. When using void pointers in calculations, the behaviour is undefined."; const std::string message = "'" + varname + "' is of type '" + vartype + "'. When using void pointers in calculations, the behaviour is undefined.";
const std::string verbose = message + " Arithmetic operations on 'void *' is a GNU C extension, which defines the 'sizeof(void)' to be 1."; const std::string verbose = message + " Arithmetic operations on 'void *' is a GNU C extension, which defines the 'sizeof(void)' to be 1.";
reportError(tok, Severity::portability, "arithOperationsOnVoidPointer", message + "\n" + verbose); reportError(tok, Severity::portability, "arithOperationsOnVoidPointer", message + "\n" + verbose);
} }

4
lib/checksizeof.h
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@ -97,7 +97,7 @@ private:
void sizeofForNumericParameterError(const Token* tok); void sizeofForNumericParameterError(const Token* tok);
void sizeofVoidError(const Token *tok); void sizeofVoidError(const Token *tok);
void sizeofDereferencedVoidPointerError(const Token *tok, const std::string &varname); void sizeofDereferencedVoidPointerError(const Token *tok, const std::string &varname);
void arithOperationsOnVoidPointerError(const Token* tok, const std::string &varname); void arithOperationsOnVoidPointerError(const Token* tok, const std::string &varname, const std::string &vartype);
void getErrorMessages(ErrorLogger* errorLogger, const Settings* settings) const { void getErrorMessages(ErrorLogger* errorLogger, const Settings* settings) const {
CheckSizeof c(0, settings, errorLogger); CheckSizeof c(0, settings, errorLogger);
@ -111,7 +111,7 @@ private:
c.divideSizeofError(0); c.divideSizeofError(0);
c.sizeofVoidError(0); c.sizeofVoidError(0);
c.sizeofDereferencedVoidPointerError(0, "varname"); c.sizeofDereferencedVoidPointerError(0, "varname");
c.arithOperationsOnVoidPointerError(0, "varname"); c.arithOperationsOnVoidPointerError(0, "varname", "vartype");
} }
static std::string myName() { static std::string myName() {

27
test/testsizeof.cpp
View File

@ -531,6 +531,33 @@ private:
" int j = sizeof(*p1);\n" " int j = sizeof(*p1);\n"
"}"); "}");
ASSERT_EQUALS("", errout.str()); ASSERT_EQUALS("", errout.str());
// Calculations on void* with casts
check("void f(void *data) {\n"
" *((unsigned char *)data + 1) = 0;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(void *data) {\n"
" *((unsigned char *)(data) + 1) = 0;\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(void *data) {\n"
" unsigned char* c = (unsigned char *)(data + 1);\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (portability) 'data' is of type 'void *'. When using void pointers in calculations, the behaviour is undefined.\n", errout.str());
check("void f(void *data) {\n"
" unsigned char* c = (unsigned char *)data++;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (portability) 'data' is of type 'void *'. When using void pointers in calculations, the behaviour is undefined.\n", errout.str());
check("void f(void *data) {\n"
" void* data2 = (void *)data + 1;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (portability) 'data' is of type 'void *'. When using void pointers in calculations, the behaviour is undefined.\n", errout.str());
} }
}; };