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Uninitialized variables: improved checking of loops

This commit is contained in:
Daniel Marjamäki 2013-01-24 19:41:15 +01:00
parent c2608108dd
commit c235737b6c
3 changed files with 129 additions and 51 deletions
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86
lib/checkuninitvar.cpp
View File

@ -25,6 +25,7 @@
#include "symboldatabase.h"
#include <algorithm>
#include <map>
#include <cassert>
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
@ -1288,8 +1289,8 @@ bool CheckUninitVar::checkScopeForVariable(const Scope* scope, const Token *tok,
const Token *tok2 = tok->next()->link()->next();
if (tok2 && tok2->str() == "{") {
bool possibleinit = true;
bool init = checkScopeForVariable(scope, tok2->next(), var, &possibleinit, NULL, membervar);
bool possibleinit = false;
bool init = checkLoopBody(scope, tok2, var, membervar);
// variable is initialized in the loop..
if (possibleinit || init)
@ -1350,21 +1351,12 @@ bool CheckUninitVar::checkScopeForVariable(const Scope* scope, const Token *tok,
// variable is seen..
if (tok->varId() == var.varId()) {
if (!membervar.empty()) {
if (Token::Match(tok, "%var% . %var%") && tok->strAt(2) == membervar) {
if (Token::Match(tok->tokAt(3), "[=.[]"))
return true;
else if (Token::Match(tok->tokAt(-2), "[(,=] &"))
return true;
else if (Token::Match(tok->previous(), "%op%") || Token::Match(tok->previous(), "[|="))
uninitStructMemberError(tok, tok->str() + "." + membervar);
else
return true;
} else if (tok->strAt(1) == "=")
if (isMemberVariableAssignment(tok, membervar))
return true;
else if (tok->strAt(-1) == "&")
return true;
else if (Token::Match(tok->previous(), "[(,] %var% [,)]") && isVariableUsage(scope, tok, var.isPointer()))
if (isMemberVariableUsage(scope, tok, var.isPointer(), membervar))
uninitStructMemberError(tok, tok->str() + "." + membervar);
} else {
// Use variable
if (!suppressErrors && isVariableUsage(scope, tok, var.isPointer()))
@ -1407,6 +1399,40 @@ bool CheckUninitVar::checkIfForWhileHead(const Scope *scope, const Token *startp
return false;
}
bool CheckUninitVar::checkLoopBody(const Scope* scope, const Token *tok, const Variable& var, const std::string &membervar)
{
const Token *usetok = NULL;
assert(tok->str() == "{");
for (const Token * const end = tok->link(); tok != end; tok = tok->next()) {
if (tok->varId() == var.varId()) {
if (!membervar.empty()) {
if (isMemberVariableAssignment(tok, membervar))
return true;
if (isMemberVariableUsage(scope, tok, var.isPointer(), membervar))
usetok = tok;
} else {
if (isVariableUsage(scope, tok, var.isPointer()))
usetok = tok;
else
return true;
}
}
}
if (usetok) {
if (membervar.empty())
uninitvarError(usetok, usetok->str());
else
uninitStructMemberError(usetok, usetok->str() + "." + membervar);
return true;
}
return false;
}
bool CheckUninitVar::isVariableUsage(const Scope* scope, const Token *vartok, bool pointer) const
{
if (vartok->previous()->str() == "return")
@ -1519,6 +1545,36 @@ bool CheckUninitVar::isVariableUsage(const Scope* scope, const Token *vartok, bo
return false;
}
bool CheckUninitVar::isMemberVariableAssignment(const Token *tok, const std::string &membervar) const
{
if (Token::Match(tok, "%var% . %var%") && tok->strAt(2) == membervar) {
if (Token::Match(tok->tokAt(3), "[=.[]"))
return true;
else if (Token::Match(tok->tokAt(-2), "[(,=] &"))
return true;
else if (Token::Match(tok->previous(), "%op%") || Token::Match(tok->previous(), "[|="))
; // member variable usage
else
return true;
} else if (tok->strAt(1) == "=")
return true;
else if (tok->strAt(-1) == "&")
return true;
return false;
}
bool CheckUninitVar::isMemberVariableUsage(const Scope *scope, const Token *tok, bool isPointer, const std::string &membervar) const
{
if (isMemberVariableAssignment(tok, membervar))
return false;
if (Token::Match(tok, "%var% . %var%") && tok->strAt(2) == membervar)
return true;
else if (Token::Match(tok->previous(), "[(,] %var% [,)]") && isVariableUsage(scope, tok, isPointer))
return true;
return false;
}
void CheckUninitVar::uninitstringError(const Token *tok, const std::string &varname, bool strncpy_)
{

4
lib/checkuninitvar.h
View File

@ -66,8 +66,10 @@ public:
void checkScope(const Scope* scope);
bool checkScopeForVariable(const Scope* scope, const Token *tok, const Variable& var, bool * const possibleInit, bool * const noreturn, const std::string &membervar);
bool checkIfForWhileHead(const Scope *scope, const Token *startparentheses, const Variable& var, bool suppressErrors, bool isuninit, const std::string &membervar);
bool checkLoopBody(const Scope* scope, const Token *tok, const Variable& var, const std::string &membervar);
bool isVariableUsage(const Scope* scope, const Token *vartok, bool ispointer) const;
bool isMemberVariableAssignment(const Token *tok, const std::string &membervar) const;
bool isMemberVariableUsage(const Scope *scope, const Token *tok, bool isPointer, const std::string &membervar) const;
/**
* @brief Uninitialized variables: analyse functions to see how they work with uninitialized variables

90
test/testuninitvar.cpp
View File

@ -2151,41 +2151,6 @@ private:
"}\n");
ASSERT_EQUALS("[test.cpp:5]: (error) Uninitialized variable: x\n", errout.str());
// for, while
checkUninitVar2("void f() {\n"
" int x;\n"
" while (a) {\n"
" if (b) x++;\n"
" else x = 0;\n"
" }\n"
"}\n");
ASSERT_EQUALS("", errout.str());
checkUninitVar2("void f() {\n"
" int x;\n"
" for (int i = 0; i < 10; i += x) {\n"
" x = y;\n"
" }\n"
"}\n");
ASSERT_EQUALS("", errout.str());
checkUninitVar2("void f() {\n"
" int x;\n"
" for (int i = 0; i < 10; i += x) { }\n"
"}\n");
ASSERT_EQUALS("[test.cpp:3]: (error) Uninitialized variable: x\n", errout.str());
checkUninitVar2("int f() {\n"
" int i;\n"
" for (i=0;i<9;++i)\n"
" if (foo()) goto out;\n"
"out:\n"
" return i;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
checkUninitVar2(">{ x while (y) z int = }"); // #4175 : don't crash
// try
checkUninitVar2("void f() {\n"
" int i, *p = &i;\n"
@ -2674,6 +2639,41 @@ private:
}
void uninitvar2_while() {
// for, while
checkUninitVar2("void f() {\n"
" int x;\n"
" while (a) {\n"
" if (b) x++;\n"
" else x = 0;\n"
" }\n"
"}\n");
ASSERT_EQUALS("", errout.str());
checkUninitVar2("void f() {\n"
" int x;\n"
" for (int i = 0; i < 10; i += x) {\n"
" x = y;\n"
" }\n"
"}\n");
ASSERT_EQUALS("", errout.str());
checkUninitVar2("void f() {\n"
" int x;\n"
" for (int i = 0; i < 10; i += x) { }\n"
"}\n");
ASSERT_EQUALS("[test.cpp:3]: (error) Uninitialized variable: x\n", errout.str());
checkUninitVar2("int f() {\n"
" int i;\n"
" for (i=0;i<9;++i)\n"
" if (foo()) goto out;\n"
"out:\n"
" return i;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
checkUninitVar2(">{ x while (y) z int = }"); // #4175 : don't crash
checkUninitVar2("int f(void) {\n"
" int x;\n"
" while (a()) {\n" // <- condition must always be true or there will be problem
@ -2685,6 +2685,26 @@ private:
" return x;\n"
"}\n", "test.c", true);
TODO_ASSERT_EQUALS("error", "", errout.str());
checkUninitVar2("void f(void) {\n"
" int x;\n"
" for (;;) {\n"
" int a = x+1;\n"
" do_something(a);\n"
" }\n"
"}\n");
ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: x\n", errout.str());
checkUninitVar2("struct AB {int a; int b;};\n"
"void f(void) {\n"
" struct AB ab;\n"
" while (true) {\n"
" int a = 1+ab.a;\n"
" do_something(a);\n"
" }\n"
"}\n", "test.c");
ASSERT_EQUALS("[test.c:5]: (error) Uninitialized variable: ab\n"
"[test.c:5]: (error) Uninitialized struct member: ab.a\n", errout.str());
}
void uninitvar2_4494() {