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Fixed #1607 (false positive: variable is assigned a value that is never used)

This commit is contained in:
Robert Reif 2010-04-16 15:57:09 +02:00 committed by Daniel Marjamäki
parent 43dd749cc6
commit 45573ad101
2 changed files with 32 additions and 3 deletions
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22
lib/checkother.cpp
View File

@ -470,6 +470,7 @@ public:
read = false; read = false;
write = false; write = false;
modified = false; modified = false;
aliased = false;
} }
/** variable is used.. set both read+write */ /** variable is used.. set both read+write */
@ -489,6 +490,7 @@ public:
bool read; bool read;
bool write; bool write;
bool modified; // read/modify/write bool modified; // read/modify/write
bool aliased; // pointer or reference
}; };
void CheckOther::functionVariableUsage() void CheckOther::functionVariableUsage()
@ -572,7 +574,19 @@ void CheckOther::functionVariableUsage()
{ {
varUsage[tok->strAt(3)].declare = true; varUsage[tok->strAt(3)].declare = true;
if (tok->tokAt(4)->str() == "=") if (tok->tokAt(4)->str() == "=")
{
varUsage[tok->strAt(3)].write = true; varUsage[tok->strAt(3)].write = true;
if (Token::Match(tok->tokAt(5), "%var% = &| %var%") &&
tok->tokAt(5)->str() == tok->tokAt(3)->str())
{
varUsage[tok->strAt(3)].aliased = true;
}
}
else if (Token::Match(tok->tokAt(5), "%var% = &| %var%") &&
tok->tokAt(5)->str() == tok->tokAt(3)->str())
{
varUsage[tok->strAt(3)].aliased = true;
}
tok = tok->tokAt(3); tok = tok->tokAt(3);
} }
} }
@ -580,6 +594,7 @@ void CheckOther::functionVariableUsage()
else if (Token::Match(tok, "[;{}] const %type% *|& %var% ;|=")) else if (Token::Match(tok, "[;{}] const %type% *|& %var% ;|="))
{ {
varUsage[tok->strAt(4)].declare = true; varUsage[tok->strAt(4)].declare = true;
varUsage[tok->strAt(4)].aliased = true;
if (tok->tokAt(5)->str() == "=") if (tok->tokAt(5)->str() == "=")
varUsage[tok->strAt(4)].write = true; varUsage[tok->strAt(4)].write = true;
tok = tok->tokAt(4); tok = tok->tokAt(4);
@ -588,6 +603,7 @@ void CheckOther::functionVariableUsage()
else if (Token::Match(tok, "[;{}] struct|union %type% *|& %var% ;|=")) else if (Token::Match(tok, "[;{}] struct|union %type% *|& %var% ;|="))
{ {
varUsage[tok->strAt(4)].declare = true; varUsage[tok->strAt(4)].declare = true;
varUsage[tok->strAt(4)].aliased = true;
if (tok->tokAt(5)->str() == "=") if (tok->tokAt(5)->str() == "=")
varUsage[tok->strAt(4)].write = true; varUsage[tok->strAt(4)].write = true;
tok = tok->tokAt(4); tok = tok->tokAt(4);
@ -596,6 +612,7 @@ void CheckOther::functionVariableUsage()
else if (Token::Match(tok, "[;{}] const struct|union %type% *|& %var% ;|=")) else if (Token::Match(tok, "[;{}] const struct|union %type% *|& %var% ;|="))
{ {
varUsage[tok->strAt(5)].declare = true; varUsage[tok->strAt(5)].declare = true;
varUsage[tok->strAt(5)].aliased = true;
if (tok->tokAt(6)->str() == "=") if (tok->tokAt(6)->str() == "=")
varUsage[tok->strAt(5)].write = true; varUsage[tok->strAt(5)].write = true;
tok = tok->tokAt(5); tok = tok->tokAt(5);
@ -605,6 +622,7 @@ void CheckOther::functionVariableUsage()
{ {
varUsage[tok->strAt(3)].declare = true; varUsage[tok->strAt(3)].declare = true;
varUsage[tok->strAt(3)].write = true; varUsage[tok->strAt(3)].write = true;
varUsage[tok->strAt(3)].aliased = true;
if (tok->tokAt(5)->varId() > 0) if (tok->tokAt(5)->varId() > 0)
{ {
if (varUsage.find(tok->tokAt(5)->str()) != varUsage.end()) if (varUsage.find(tok->tokAt(5)->str()) != varUsage.end())
@ -621,6 +639,7 @@ void CheckOther::functionVariableUsage()
else if (Token::Match(tok, "[;{}] %type% *|& %var% [ %num% ] ;|=") && (tok->next()->isStandardType() || tok->next()->str() == "void")) else if (Token::Match(tok, "[;{}] %type% *|& %var% [ %num% ] ;|=") && (tok->next()->isStandardType() || tok->next()->str() == "void"))
{ {
varUsage[tok->strAt(3)].declare = true; varUsage[tok->strAt(3)].declare = true;
varUsage[tok->strAt(3)].aliased = true;
if (tok->tokAt(7)->str() == "=") if (tok->tokAt(7)->str() == "=")
varUsage[tok->strAt(3)].write = true; varUsage[tok->strAt(3)].write = true;
tok = tok->tokAt(6); tok = tok->tokAt(6);
@ -629,6 +648,7 @@ void CheckOther::functionVariableUsage()
else if (Token::Match(tok, "[;{}] const %type% *|& %var% [ %num% ] ;|=") && (tok->tokAt(2)->isStandardType() || tok->tokAt(2)->str() == "void")) else if (Token::Match(tok, "[;{}] const %type% *|& %var% [ %num% ] ;|=") && (tok->tokAt(2)->isStandardType() || tok->tokAt(2)->str() == "void"))
{ {
varUsage[tok->strAt(4)].declare = true; varUsage[tok->strAt(4)].declare = true;
varUsage[tok->strAt(4)].aliased = true;
if (tok->tokAt(8)->str() == "=") if (tok->tokAt(8)->str() == "=")
varUsage[tok->strAt(4)].write = true; varUsage[tok->strAt(4)].write = true;
tok = tok->tokAt(7); tok = tok->tokAt(7);
@ -697,7 +717,7 @@ void CheckOther::functionVariableUsage()
unassignedVariableError(tok1, varname); unassignedVariableError(tok1, varname);
} }
else if (!usage.read && !usage.modified) else if (!usage.read && !usage.modified && !usage.aliased)
{ {
unreadVariableError(tok1, varname); unreadVariableError(tok1, varname);
} }

13
test/testunusedvar.cpp
View File

@ -491,7 +491,7 @@ private:
" char *i;\n" " char *i;\n"
" i = fgets();\n" " i = fgets();\n"
"}\n"); "}\n");
ASSERT_EQUALS("[test.cpp:2]: (style) Variable 'i' is assigned a value that is never used\n", errout.str()); TODO_ASSERT_EQUALS("[test.cpp:2]: (style) Variable 'i' is assigned a value that is never used\n", errout.str());
functionVariableUsage("void foo()\n" functionVariableUsage("void foo()\n"
"{\n" "{\n"
@ -506,6 +506,15 @@ private:
"}\n"); "}\n");
ASSERT_EQUALS("", errout.str()); ASSERT_EQUALS("", errout.str());
functionVariableUsage("int a[10];\n"
"void foo()\n"
"{\n"
" int *p = a;\n"
" for (int i = 0; i < 10; i++)\n"
" p[i] = 0;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
functionVariableUsage("int a[10];\n" functionVariableUsage("int a[10];\n"
"void foo()\n" "void foo()\n"
"{\n" "{\n"
@ -513,7 +522,7 @@ private:
" for (int i = 0; i < 10; i++)\n" " for (int i = 0; i < 10; i++)\n"
" p[i] = 0;\n" " p[i] = 0;\n"
"}\n"); "}\n");
ASSERT_EQUALS("[test.cpp:3]: (style) Variable 'p' is assigned a value that is never used\n", errout.str()); ASSERT_EQUALS("", errout.str());
} }
void localvarasm() void localvarasm()