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Fixed TODO (check if function parameter is non-const reference etc..) by common function

This commit is contained in:
Frank Zingsheim 2016-10-23 13:54:44 +02:00
parent a91c54df72
commit d4f01583b6
8 changed files with 178 additions and 91 deletions
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2
Makefile
View File

@ -303,7 +303,7 @@ endif
$(SRCDIR)/analyzerinfo.o: lib/analyzerinfo.cpp lib/cxx11emu.h lib/analyzerinfo.h lib/config.h lib/errorlogger.h lib/suppressions.h lib/path.h
$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CFG) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o $(SRCDIR)/analyzerinfo.o $(SRCDIR)/analyzerinfo.cpp
$(SRCDIR)/astutils.o: lib/astutils.cpp lib/cxx11emu.h lib/astutils.h lib/symboldatabase.h lib/config.h lib/token.h lib/valueflow.h lib/mathlib.h lib/tokenize.h lib/errorlogger.h lib/suppressions.h lib/tokenlist.h
$(SRCDIR)/astutils.o: lib/astutils.cpp lib/cxx11emu.h lib/astutils.h lib/settings.h lib/config.h lib/library.h lib/mathlib.h lib/standards.h lib/errorlogger.h lib/suppressions.h lib/platform.h lib/importproject.h lib/timer.h lib/symboldatabase.h lib/token.h lib/valueflow.h lib/tokenize.h lib/tokenlist.h
$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CFG) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o $(SRCDIR)/astutils.o $(SRCDIR)/astutils.cpp
$(SRCDIR)/check.o: lib/check.cpp lib/cxx11emu.h lib/check.h lib/config.h lib/token.h lib/valueflow.h lib/mathlib.h lib/tokenize.h lib/errorlogger.h lib/suppressions.h lib/tokenlist.h lib/settings.h lib/library.h lib/standards.h lib/platform.h lib/importproject.h lib/timer.h

79
lib/astutils.cpp
View File

@ -19,6 +19,7 @@
//---------------------------------------------------------------------------
#include "astutils.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
@ -341,7 +342,69 @@ bool isReturnScope(const Token * const endToken)
return false;
}
bool isVariableChanged(const Token *start, const Token *end, const unsigned int varid)
bool isVariableChangedByFunctionCall(const Token *tok, const Settings *settings, bool *inconclusive)
{
if (!tok)
return false;
// address of variable
const bool addressOf = tok && Token::simpleMatch(tok->previous(), "&");
// passing variable to subfunction?
if (Token::Match(tok->tokAt(-2), ") & %name% [,)]") && Token::Match(tok->linkAt(-2)->previous(), "[,(] ("))
;
else if (Token::Match(tok->tokAt(addressOf?-2:-1), "[(,] &| %name% [,)]"))
;
else
return false;
// reinterpret_cast etc..
if (Token::Match(tok->tokAt(-3), "> ( & %name% ) [,)]") &&
tok->linkAt(-3) &&
Token::Match(tok->linkAt(-3)->tokAt(-2), "[,(] %type% <"))
tok = tok->linkAt(-3);
// goto start of function call and get argnr
unsigned int argnr = 0;
while (tok && tok->str() != "(") {
if (tok->str() == ",")
++argnr;
else if (tok->str() == ")")
tok = tok->link();
tok = tok->previous();
}
tok = tok ? tok->previous() : nullptr;
if (tok && tok->link() && tok->str() == ">")
tok = tok->link()->previous();
if (!Token::Match(tok, "%name% ("))
return false; // not a function => variable not changed
if (tok->varId())
return false; // Constructor call of tok => variable probably not changed by constructor call
if (!tok->function()) {
// if the library says 0 is invalid
// => it is assumed that parameter is an in parameter (TODO: this is a bad heuristic)
if (!addressOf && settings->library.isnullargbad(tok, 1+argnr))
return false;
// addressOf => inconclusive
if (!addressOf) {
if (inconclusive != nullptr)
*inconclusive = true;
return false;
}
return true;
}
const Variable *arg = tok->function()->getArgumentVar(argnr);
if (addressOf && !(arg && arg->isConst()))
return true;
return arg && !arg->isConst() && arg->isReference();
}
bool isVariableChanged(const Token *start, const Token *end, const unsigned int varid, const Settings *settings)
{
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (tok->varId() == varid) {
@ -351,17 +414,11 @@ bool isVariableChanged(const Token *start, const Token *end, const unsigned int
if (Token::Match(tok->previous(), "++|-- %name%"))
return true;
if (Token::Match(tok->tokAt(-2), "[(,] & %var% [,)]"))
return true; // TODO: check if function parameter is const
if (Token::Match(tok->previous(), "[(,] %var% [,)]")) {
const Token *parent = tok->astParent();
while (parent && parent->str() == ",")
parent = parent->astParent();
if (parent && Token::Match(parent->previous(), "%name% (") && !parent->previous()->function())
bool inconclusive = false;
bool isChanged = isVariableChangedByFunctionCall(tok, settings, &inconclusive);
isChanged |= inconclusive;
if (isChanged)
return true;
// TODO: check if function parameter is non-const reference etc..
}
const Token *parent = tok->astParent();
while (Token::Match(parent, ".|::"))

13
lib/astutils.h
View File

@ -25,6 +25,7 @@
#include <set>
#include <string>
class Settings;
class Token;
/** Is expression a 'signed char' if no promotion is used */
@ -71,8 +72,18 @@ bool isWithoutSideEffects(bool cpp, const Token* tok);
/** Is scope a return scope (scope will unconditionally return) */
bool isReturnScope(const Token *endToken);
/** Is variable changed by function call?
* In case the anser of the question is inconclusive, e.g. because the function declaration is not known
* the return value is false and the output parameter inconclusive is set to true
*
* @param tok token of varible in function call
* @param settings program settings
* @param inconclusive pointer to output variable which indicates that the answer of the question is inconclusive
*/
bool isVariableChangedByFunctionCall(const Token *tok, const Settings *settings, bool *inconclusive);
/** Is variable changed in block of code? */
bool isVariableChanged(const Token *start, const Token *end, const unsigned int varid);
bool isVariableChanged(const Token *start, const Token *end, const unsigned int varid, const Settings *settings);
/** Determines the number of arguments - if token is a function call or macro
* @param start token which is supposed to be the function/macro name.

2
lib/checkcondition.cpp
View File

@ -151,7 +151,7 @@ bool CheckCondition::assignIfParseScope(const Token * const assignTok,
// is variable changed in loop?
const Token *bodyStart = tok2->linkAt(1)->next();
const Token *bodyEnd = bodyStart ? bodyStart->link() : nullptr;
if (!bodyEnd || bodyEnd->str() != "}" || isVariableChanged(bodyStart, bodyEnd, varid))
if (!bodyEnd || bodyEnd->str() != "}" || isVariableChanged(bodyStart, bodyEnd, varid, _settings))
continue;
}

94
lib/valueflow.cpp
View File

@ -87,63 +87,6 @@ static void bailout(TokenList *tokenlist, ErrorLogger *errorLogger, const Token
errorLogger->reportErr(errmsg);
}
static bool bailoutFunctionPar(const Token *tok, const ValueFlow::Value &value, const Settings *settings, bool *inconclusive)
{
if (!tok)
return false;
// address of variable
const bool addressOf = tok && Token::simpleMatch(tok->previous(), "&");
// passing variable to subfunction?
if (Token::Match(tok->tokAt(-2), ") & %name% [,)]") && Token::Match(tok->linkAt(-2)->previous(), "[,(] ("))
;
else if (Token::Match(tok->tokAt(addressOf?-2:-1), "[(,] &| %name% [,)]"))
;
else
return false;
// reinterpret_cast etc..
if (Token::Match(tok->tokAt(-3), "> ( & %name% ) [,)]") &&
tok->linkAt(-3) &&
Token::Match(tok->linkAt(-3)->tokAt(-2), "[,(] %type% <"))
tok = tok->linkAt(-3);
// goto start of function call and get argnr
unsigned int argnr = 0;
while (tok && tok->str() != "(") {
if (tok->str() == ",")
++argnr;
else if (tok->str() == ")")
tok = tok->link();
tok = tok->previous();
}
tok = tok ? tok->previous() : nullptr;
if (tok && tok->link() && tok->str() == ">")
tok = tok->link()->previous();
if (!Token::Match(tok, "%name% ("))
return false; // not a function => do not bailout
if (!tok->function()) {
// if value is 0 and the library says 0 is invalid => do not bailout
if (value.intvalue==0 && settings->library.isnullargbad(tok, 1+argnr))
return false;
// addressOf => inconclusive
if (!addressOf) {
*inconclusive = true;
return false;
}
return true;
}
const Variable *arg = tok->function()->getArgumentVar(argnr);
if (addressOf && !(arg && arg->isConst()))
return true;
return arg && !arg->isConst() && arg->isReference();
}
/**
* Is condition always false when variable has given value?
* \param condition top ast token in condition
@ -891,7 +834,7 @@ static void valueFlowReverse(TokenList *tokenlist,
// assigned by subfunction?
bool inconclusive = false;
if (bailoutFunctionPar(tok2,val2.condition ? val2 : val, settings, &inconclusive)) {
if (isVariableChangedByFunctionCall(tok2, settings, &inconclusive)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction");
break;
@ -950,7 +893,7 @@ static void valueFlowReverse(TokenList *tokenlist,
const Token *start = tok2;
const Token *end = start->link();
if (isVariableChanged(start,end,varid)) {
if (isVariableChanged(start,end,varid, settings)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " is assigned in loop. so valueflow analysis bailout when start of loop is reached.");
break;
@ -1029,7 +972,7 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, SymbolDatabase *symbo
// Variable changed in 3rd for-expression
if (Token::simpleMatch(tok2->previous(), "for (")) {
if (tok2->astOperand2() && tok2->astOperand2()->astOperand2() && isVariableChanged(tok2->astOperand2()->astOperand2(), tok2->link(), varid)) {
if (tok2->astOperand2() && tok2->astOperand2()->astOperand2() && isVariableChanged(tok2->astOperand2()->astOperand2(), tok2->link(), varid, settings)) {
varid = 0U;
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "variable " + var->name() + " used in loop");
@ -1041,7 +984,7 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, SymbolDatabase *symbo
const Token * const start = tok2->link()->next();
const Token * const end = start->link();
if (isVariableChanged(start,end,varid)) {
if (isVariableChanged(start,end,varid, settings)) {
varid = 0U;
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "variable " + var->name() + " used in loop");
@ -1134,13 +1077,14 @@ static void valueFlowAST(Token *tok, unsigned int varid, const ValueFlow::Value
static void handleKnownValuesInLoop(const Token *startToken,
const Token *endToken,
std::list<ValueFlow::Value> *values,
unsigned int varid)
unsigned int varid,
const Settings *settings)
{
bool isChanged = false;
for (std::list<ValueFlow::Value>::iterator it = values->begin(); it != values->end(); ++it) {
if (it->isKnown()) {
if (!isChanged) {
if (!isVariableChanged(startToken, endToken, varid))
if (!isVariableChanged(startToken, endToken, varid, settings))
break;
isChanged = true;
}
@ -1239,19 +1183,19 @@ static bool valueFlowForward(Token * const startToken,
if (Token::simpleMatch(end, "} while ("))
end = end->linkAt(2);
if (isVariableChanged(start, end, varid)) {
if (isVariableChanged(start, end, varid, settings)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, assignment in do-while");
return false;
}
handleKnownValuesInLoop(start, end, &values, varid);
handleKnownValuesInLoop(start, end, &values, varid, settings);
}
// conditional block of code that assigns variable..
else if (Token::Match(tok2, "%name% (") && Token::simpleMatch(tok2->linkAt(1), ") {")) {
// is variable changed in condition?
if (isVariableChanged(tok2->next(), tok2->next()->link(), varid)) {
if (isVariableChanged(tok2->next(), tok2->next()->link(), varid, settings)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, assignment in condition");
return false;
@ -1259,7 +1203,7 @@ static bool valueFlowForward(Token * const startToken,
// if known variable is changed in loop body, change it to a possible value..
if (Token::Match(tok2, "for|while"))
handleKnownValuesInLoop(tok2, tok2->linkAt(1)->linkAt(1), &values, varid);
handleKnownValuesInLoop(tok2, tok2->linkAt(1)->linkAt(1), &values, varid, settings);
// Set values in condition
for (Token* tok3 = tok2->tokAt(2); tok3 != tok2->next()->link(); tok3 = tok3->next()) {
@ -1294,7 +1238,7 @@ static bool valueFlowForward(Token * const startToken,
errorLogger,
settings);
if (isVariableChanged(startToken1, startToken1->link(), varid)) {
if (isVariableChanged(startToken1, startToken1->link(), varid, settings)) {
removeValues(values, truevalues);
std::list<ValueFlow::Value>::iterator it;
@ -1314,7 +1258,7 @@ static bool valueFlowForward(Token * const startToken,
Token * const start = tok2->linkAt(1)->next();
Token * const end = start->link();
bool varusage = (indentlevel >= 0 && constValue && number_of_if == 0U) ?
isVariableChanged(start,end,varid) :
isVariableChanged(start,end,varid, settings) :
(nullptr != Token::findmatch(start, "%varid%", end, varid));
if (!read) {
read = bool(nullptr != Token::findmatch(tok2, "%varid% !!=", end, varid));
@ -1383,7 +1327,7 @@ static bool valueFlowForward(Token * const startToken,
return false;
}
if (isVariableChanged(start, end, varid)) {
if (isVariableChanged(start, end, varid, settings)) {
if ((!read || number_of_if == 0) &&
Token::simpleMatch(tok2, "if (") &&
!(Token::simpleMatch(end, "} else {") &&
@ -1623,7 +1567,7 @@ static bool valueFlowForward(Token * const startToken,
// assigned by subfunction?
bool inconclusive = false;
if (bailoutFunctionPar(tok2, ValueFlow::Value(), settings, &inconclusive)) {
if (isVariableChangedByFunctionCall(tok2, settings, &inconclusive)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "possible assignment of " + tok2->str() + " by subfunction");
return false;
@ -1642,7 +1586,7 @@ static bool valueFlowForward(Token * const startToken,
Token::simpleMatch(tok2->linkAt(1), "] (") &&
Token::simpleMatch(tok2->linkAt(1)->linkAt(1), ") {")) {
const Token *bodyStart = tok2->linkAt(1)->linkAt(1)->next();
if (isVariableChanged(bodyStart, bodyStart->link(), varid)) {
if (isVariableChanged(bodyStart, bodyStart->link(), varid, settings)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "valueFlowForward, " + var->name() + " is changed in lambda function");
return false;
@ -1788,7 +1732,7 @@ static void valueFlowAfterCondition(TokenList *tokenlist, SymbolDatabase* symbol
// does condition reassign variable?
if (tok != top->astOperand2() &&
Token::Match(top->astOperand2(), "%oror%|&&") &&
isVariableChanged(top, top->link(), varid)) {
isVariableChanged(top, top->link(), varid, settings)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "assignment in condition");
continue;
@ -1823,7 +1767,7 @@ static void valueFlowAfterCondition(TokenList *tokenlist, SymbolDatabase* symbol
if (startToken) {
if (!valueFlowForward(startToken->next(), startToken->link(), var, varid, values, true, tokenlist, errorLogger, settings))
continue;
if (isVariableChanged(startToken, startToken->link(), varid)) {
if (isVariableChanged(startToken, startToken->link(), varid, settings)) {
// TODO: The endToken should not be startToken->link() in the valueFlowForward call
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, startToken->link(), "valueFlowAfterCondition: " + var->name() + " is changed in conditional block");
@ -2119,7 +2063,7 @@ static void valueFlowForLoopSimplify(Token * const bodyStart, const unsigned int
const Token * const bodyEnd = bodyStart->link();
// Is variable modified inside for loop
if (isVariableChanged(bodyStart, bodyEnd, varid))
if (isVariableChanged(bodyStart, bodyEnd, varid, settings))
return;
for (Token *tok2 = bodyStart->next(); tok2 != bodyEnd; tok2 = tok2->next()) {

47
test/testcondition.cpp
View File

@ -193,6 +193,26 @@ private:
"}");
ASSERT_EQUALS("", errout.str());
check("void g(int x);\n"
"void f(int x) {\n"
" int a = 100;\n"
" while (x) {\n"
" int y = 16 | a;\n"
" while (y != 0) g(y);\n"
" }\n"
"}");
ASSERT_EQUALS("[test.cpp:6]: (style) Condition 'y!=0' is always true\n[test.cpp:5] -> [test.cpp:6]: (style) Mismatching assignment and comparison, comparison 'y!=0' is always true.\n", errout.str());
check("void g(int &x);\n"
"void f(int x) {\n"
" int a = 100;\n"
" while (x) {\n"
" int y = 16 | a;\n"
" while (y != 0) g(y);\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
// calling function
check("void f(int x) {\n"
" int y = x & 7;\n"
@ -293,6 +313,33 @@ private:
" }\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("void f() {\n"
" int x = 100;\n"
" while (x) {\n"
" g(x);\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void g(int x);\n"
"void f() {\n"
" int x = 100;\n"
" while (x) {\n"
" g(x);\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void g(int & x);\n"
"void f() {\n"
" int x = 100;\n"
" while (x) {\n"
" g(x);\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void mismatchingBitAnd() {

2
test/testnullpointer.cpp
View File

@ -2503,7 +2503,7 @@ private:
void ticket6505() {
check("void foo(MythSocket *socket) {\n"
" bool do_write=false;\n"
" bool do_write=0;\n"
" if (socket) {\n"
" do_write=something();\n"
" }\n"

28
test/testvalueflow.cpp
View File

@ -1865,6 +1865,34 @@ private:
"}\n";
ASSERT(isNotKnownValues(code, "<"));
code = "void dostuff(int x);\n"
"void f() {\n"
" int x = 0;\n"
" dostuff(x);\n"
" if (x < 0) {}\n"
"}\n";
value = valueOfTok(code, "<");
ASSERT_EQUALS(0, value.intvalue);
ASSERT(value.isKnown());
code = "void dostuff(int & x);\n"
"void f() {\n"
" int x = 0;\n"
" dostuff(x);\n"
" if (x < 0) {}\n"
"}\n";
ASSERT(isNotKnownValues(code, "<"));
code = "void dostuff(const int & x);\n"
"void f() {\n"
" int x = 0;\n"
" dostuff(x);\n"
" if (x < 0) {}\n"
"}\n";
value = valueOfTok(code, "<");
ASSERT_EQUALS(0, value.intvalue);
ASSERT(value.isKnown());
code = "void f() {\n"
" int x = 0;\n"
" do {\n"