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Fixed #3075 (False positive => Improve tokenizer: remove redundant code after a 'return' state)

This commit is contained in:
Edoardo Prezioso 2011-09-13 07:55:47 +02:00 committed by Daniel Marjamäki
parent 302daeb9bd
commit 1ff7410f4f
6 changed files with 268 additions and 10 deletions
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193
lib/tokenize.cpp
View File

@ -2742,6 +2742,8 @@ bool Tokenizer::tokenize(std::istream &code,
}
}
removeRedundantCodeAfterReturn();
_tokens->assignProgressValues();
removeRedundantSemicolons();
@ -4543,6 +4545,8 @@ bool Tokenizer::simplifyTokenList()
simplifyGoto();
removeRedundantCodeAfterReturn();
// Combine wide strings
for (Token *tok = _tokens; tok; tok = tok->next())
{
@ -4888,6 +4892,195 @@ void Tokenizer::removeRedundantAssignment()
}
}
void Tokenizer::removeRedundantCodeAfterReturn()
{
unsigned int indentlevel = 0;
unsigned int indentcase = 0;
unsigned int indentret = 0; //this is the indentation level when 'return ;' token is found;
unsigned int indentswitch = 0;
unsigned int indentlabel = 0;
bool ret = false; //is it already found a 'return' token?
bool switched = false; //is it there a switch code?
for (Token *tok = _tokens; tok; tok = tok->next())
{
if (tok->str() == "{")
{
++indentlevel;
if (ret)
{
unsigned int indentlevel1 = indentlevel;
for (Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
{
if (tok2->str() == "{")
++indentlevel1;
else if (tok2->str() == "}")
{
if (indentlevel1 == indentlevel)
break;
--indentlevel1;
}
else if (Token::Match(tok2, "%var% : ;")
&& tok2->str()!="case" && tok2->str()!="default")
{
indentlabel = indentlevel1;
break;
}
}
if (indentlevel > indentlabel)
{
tok = tok->previous();
tok->deleteNext();
}
}
}
else if (tok->str() == "}")
{
if (indentlevel == 0)
break; // break out - it seems the code is wrong
//there's already a 'return ;' and more indentation!
if (ret)
{
if (!switched || indentlevel > indentcase)
{
if (indentlevel > indentret && indentlevel > indentlabel)
{
tok = tok->previous();
tok->deleteNext();
}
}
else
{
if (indentcase >= indentret && indentlevel > indentlabel)
{
tok = tok->previous();
tok->deleteNext();
}
}
}
if (indentlevel == indentret)
ret = false;
--indentlevel;
if (indentlevel <= indentcase)
{
if (!indentswitch)
{
indentcase = 0;
switched = false;
}
else
{
--indentswitch;
indentcase = indentlevel-1;
}
}
}
else if (!ret)
{
if (tok->str() == "switch")
{
if (indentlevel == 0)
break;
if (!switched)
{
for (Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
{
if (tok2->str() == "{")
{
switched = true;
tok = tok2;
break;
}
else if (tok2->str() == "}")
break; //bad code
}
if (!switched)
break;
++indentlevel;
indentcase = indentlevel;
}
else
{
++indentswitch;
//todo this case
}
}
else if (switched
&& (tok->str() == "case" || tok->str() == "default"))
{
if (indentlevel > indentcase)
{
--indentlevel;
}
for (Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
{
if (tok2->str() == ":" || Token::Match(tok2, ": ;"))
{
if (indentlevel == indentcase)
{
++indentlevel;
}
tok = tok2;
break;
}
else if (tok2->str() == "}" || tok2->str() == "{")
break; //bad code
}
}
else if (tok->str() == "return")
{
if (indentlevel == 0)
break; // break out - never seen a 'return' not inside a scope;
//catch the first ';' after the return
for (Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
{
if (tok2->str() == ";")
{
ret = true;
tok = tok2;
break;
}
else if (tok2->str() == "{" || tok2->str() == "}")
break; //I think this is an error code...
}
if (!ret)
break;
indentret = indentlevel;
}
}
else if (ret) //there's already a "return;" declaration
{
if (!switched || indentlevel > indentcase+1)
{
if (indentlevel >= indentret && (!(Token::Match(tok, "%var% : ;")) || tok->str()=="case" || tok->str()=="default"))
{
tok = tok->previous();
tok->deleteNext();
}
else
{
ret = false;
}
}
else
{
if (!(Token::Match(tok, "%var% : ;")) && tok -> str() != "case" && tok->str() != "default")
{
tok = tok->previous();
tok->deleteNext();
}
else
{
ret = false;
tok = tok->previous();
}
}
}
}
}
bool Tokenizer::removeReduntantConditions()
{
// Return value for function. Set to true if there are any simplifications

3
lib/tokenize.h
View File

@ -199,6 +199,9 @@ public:
/** Remove redundant assignment */
void removeRedundantAssignment();
/** Remove redudant code after return */
void removeRedundantCodeAfterReturn();
/**
* Replace sizeof() to appropriate size.
*/

14
test/testclass.cpp
View File

@ -467,8 +467,8 @@ private:
checkOpertorEqRetRefThis(
"class A {\n"
"public:\n"
" inline A &operator =(int *other) { return (*this;) };\n"
" inline A &operator =(long *other) { return (*this = 0;) };\n"
" inline A &operator =(int *other) { return (*this); };\n"
" inline A &operator =(long *other) { return (*this = 0); };\n"
"};");
ASSERT_EQUALS("", errout.str());
@ -478,14 +478,14 @@ private:
" A &operator =(int *other);\n"
" A &operator =(long *other);\n"
"};\n"
"A &A::operator =(int *other) { return (*this;) };\n"
"A &A::operator =(long *other) { return (*this = 0;) };");
"A &A::operator =(int *other) { return (*this); };\n"
"A &A::operator =(long *other) { return (*this = 0); };");
ASSERT_EQUALS("", errout.str());
checkOpertorEqRetRefThis(
"class A {\n"
"public:\n"
" inline A &operator =(int *other) { return (*this;) };\n"
" inline A &operator =(int *other) { return (*this); };\n"
" inline A &operator =(long *other) { return operator = (*(int *)other); };\n"
"};");
ASSERT_EQUALS("", errout.str());
@ -496,7 +496,7 @@ private:
" A &operator =(int *other);\n"
" A &operator =(long *other);\n"
"};\n"
"A &A::operator =(int *other) { return (*this;) };\n"
"A &A::operator =(int *other) { return (*this); };\n"
"A &A::operator =(long *other) { return operator = (*(int *)other); };");
ASSERT_EQUALS("", errout.str());
@ -506,7 +506,7 @@ private:
" A &operator =(int *other);\n"
" A &operator =(long *other);\n"
"};\n"
"A &A::operator =(int *other) { return (*this;) };\n"
"A &A::operator =(int *other) { return (*this); };\n"
"A &A::operator =(long *other) { return this->operator = (*(int *)other); };");
ASSERT_EQUALS("", errout.str());
}

17
test/testmemleak.cpp
View File

@ -349,6 +349,7 @@ private:
// #2662: segfault because of endless recursion (call_func -> getAllocationType -> functionReturnType -> call_func ..)
TEST_CASE(trac2662);
TEST_CASE(redundantCodeAfterReturnGoto);
}
@ -3838,6 +3839,22 @@ private:
"}\n");
ASSERT_EQUALS("", errout.str());
}
//ticket # 3083
void redundantCodeAfterReturnGoto()
{
check("void foo()\n"
"{\n"
" char * data;\n"
" data = NULL;\n"
" goto source;\n"
" data = (char *)malloc((10+1)*sizeof(char));\n"
"source:\n"
" data = (char *)malloc(10*sizeof(char));\n"
" free(data);\n"
"}");
ASSERT_EQUALS("",errout.str());
}
};
static TestMemleakInFunction testMemleakInFunction;

2
test/testsimplifytokens.cpp
View File

@ -441,7 +441,7 @@ private:
"}\n";
const char expected[] = "static void crash ( ) "
"{ foo ( ) ; return ; foo ( ) ; }";
"{ foo ( ) ; return ; }";
ASSERT_EQUALS(expected, tok(code));
}

49
test/testtokenize.cpp
View File

@ -355,6 +355,9 @@ private:
TEST_CASE(multipleAssignment);
TEST_CASE(simplifyIfAddBraces); // ticket # 2739 (segmentation fault)
//remove redundant code after the 'return ;' statement
TEST_CASE(removeRedundantCodeAfterReturn);
}
@ -1568,8 +1571,7 @@ private:
"{"
" int i ;"
" for ( i = 0 ; i < 10 ; ++ i ) { }"
" return ;"
" str [ i ] = 0 ; "
" return ; "
"}",
simplifyKnownVariables(code));
}
@ -5869,6 +5871,49 @@ private:
tokenizeAndStringify(code));
}
}
void removeRedundantCodeAfterReturn()
{
ASSERT_EQUALS("void f ( ) { return ; }", tokenizeAndStringify("void f() { return; foo();}"));
ASSERT_EQUALS("void f ( int n ) { if ( n ) { return ; } foo ( ) ; }",tokenizeAndStringify("void f(int n) { if (n) return; foo();}"));
ASSERT_EQUALS("int f ( int n ) { switch ( n ) { case 0 : return 0 ; default : ; return n ; } return -1 ; }",
tokenizeAndStringify("int f(int n) { switch (n) {case 0: return 0; n*=2; default: return n; n*=6;} return -1; foo();}"));
{
const char code[] = "void f(){ "
"if (k>0) goto label; "
"return; "
"if (tnt) "
" { "
" { "
" check(); "
" k=0; "
" } "
" label: "
" bar(); "
" } "
"}";
ASSERT_EQUALS("void f ( ) { if ( 0 < k ) { goto label ; } return ; { label : ; bar ( ) ; } }",simplifyKnownVariables(code));
}
{
const char code[] = "int f() { "
"switch (x) { case 1: return 1; bar(); tack; { ticak(); return; } return; "
"case 2: return 2; { reere(); } tack(); "
"switch(y) { case 1: return 0; case 2: return 7; } "
"return 2; } return 3; }";
ASSERT_EQUALS("int f ( ) { switch ( x ) { case 1 : return 1 ; case 2 : return 2 ; } return 3 ; }",simplifyKnownVariables(code));
}
{
const char code[] = "int f() { "
"switch (x) { case 1: return 1; bar(); tack; { ticak(); return; } return; "
"case 2: switch(y) { case 1: return 0; bar2(); foo(); case 2: return 7; } "
"return 2; } return 3; }";
ASSERT_EQUALS("int f ( ) { switch ( x ) { case 1 : return 1 ; case 2 : switch ( y ) { case 1 : return 0 ; case 2 : return 7 ; } return 2 ; } return 3 ; }",simplifyKnownVariables(code));
}
}
};
REGISTER_TEST(TestTokenizer)