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Fixed #3088 (False positive: Dont report "struct or union member is never used" for structs with __attribute__((packed)) or #pragma pack(push))

This commit is contained in:
Daniel Marjamäki 2020-06-30 10:59:57 +02:00
parent 0f20506063
commit 0583763cc6
6 changed files with 59 additions and 17 deletions
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12
lib/checkunusedvar.cpp
View File

@ -21,6 +21,7 @@
#include "checkunusedvar.h"
#include "astutils.h"
#include "preprocessor.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
@ -1340,6 +1341,17 @@ void CheckUnusedVar::checkStructMemberUsage()
// Packed struct => possibly used by lowlevel code. Struct members might be required by hardware.
if (scope.bodyEnd->isAttributePacked())
continue;
if (const Preprocessor *preprocessor = mTokenizer->getPreprocessor()) {
bool isPacked = false;
for (const Directive &d: preprocessor->getDirectives()) {
if (d.str == "#pragma pack(1)" && d.file == mTokenizer->list.getFiles().front() && d.linenr < scope.bodyStart->linenr()) {
isPacked=true;
break;
}
}
if (isPacked)
continue;
}
// Bail out if struct/union contains any functions
if (!scope.functionList.empty())

31
lib/cppcheck.cpp
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@ -688,16 +688,17 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
continue;
}
Tokenizer mTokenizer(&mSettings, this);
Tokenizer tokenizer(&mSettings, this);
tokenizer.setPreprocessor(&preprocessor);
if (mSettings.showtime != SHOWTIME_MODES::SHOWTIME_NONE)
mTokenizer.setTimerResults(&s_timerResults);
tokenizer.setTimerResults(&s_timerResults);
try {
// Create tokens, skip rest of iteration if failed
{
Timer timer("Tokenizer::createTokens", mSettings.showtime, &s_timerResults);
simplecpp::TokenList tokensP = preprocessor.preprocess(tokens1, mCurrentConfig, files, true);
mTokenizer.createTokens(std::move(tokensP));
tokenizer.createTokens(std::move(tokensP));
}
hasValidConfig = true;
@ -708,7 +709,7 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
mErrorLogger.reportOut("Checking " + fixedpath + ": " + mCurrentConfig + "...");
}
if (!mTokenizer.tokens())
if (!tokenizer.tokens())
continue;
// skip rest of iteration if just checking configuration
@ -716,11 +717,11 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
continue;
// Check raw tokens
checkRawTokens(mTokenizer);
checkRawTokens(tokenizer);
// Simplify tokens into normal form, skip rest of iteration if failed
Timer timer2("Tokenizer::simplifyTokens1", mSettings.showtime, &s_timerResults);
bool result = mTokenizer.simplifyTokens1(mCurrentConfig);
bool result = tokenizer.simplifyTokens1(mCurrentConfig);
timer2.stop();
if (!result)
continue;
@ -733,13 +734,13 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
fdump << " <cpp version=\"" << mSettings.standards.getCPP() << "\"/>" << std::endl;
fdump << " </standards>" << std::endl;
preprocessor.dump(fdump);
mTokenizer.dump(fdump);
tokenizer.dump(fdump);
fdump << "</dump>" << std::endl;
}
// Skip if we already met the same simplified token list
if (mSettings.force || mSettings.maxConfigs > 1) {
const unsigned long long checksum = mTokenizer.list.calculateChecksum();
const unsigned long long checksum = tokenizer.list.calculateChecksum();
if (checksums.find(checksum) != checksums.end()) {
if (mSettings.debugwarnings)
purgedConfigurationMessage(filename, mCurrentConfig);
@ -749,11 +750,11 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
}
// Check normal tokens
checkNormalTokens(mTokenizer);
checkNormalTokens(tokenizer);
// Analyze info..
if (!mSettings.buildDir.empty())
checkUnusedFunctions.parseTokens(mTokenizer, filename.c_str(), &mSettings);
checkUnusedFunctions.parseTokens(tokenizer, filename.c_str(), &mSettings);
// simplify more if required, skip rest of iteration if failed
if (mSimplify && hasRule("simple")) {
@ -761,13 +762,13 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
// if further simplification fails then skip rest of iteration
Timer timer3("Tokenizer::simplifyTokenList2", mSettings.showtime, &s_timerResults);
result = mTokenizer.simplifyTokenList2();
result = tokenizer.simplifyTokenList2();
timer3.stop();
if (!result)
continue;
if (!Settings::terminated())
executeRules("simple", mTokenizer);
executeRules("simple", tokenizer);
}
} catch (const simplecpp::Output &o) {
@ -779,16 +780,16 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
} catch (const InternalError &e) {
std::list<ErrorMessage::FileLocation> locationList;
if (e.token) {
ErrorMessage::FileLocation loc(e.token, &mTokenizer.list);
ErrorMessage::FileLocation loc(e.token, &tokenizer.list);
locationList.push_back(loc);
} else {
ErrorMessage::FileLocation loc(mTokenizer.list.getSourceFilePath(), 0, 0);
ErrorMessage::FileLocation loc(tokenizer.list.getSourceFilePath(), 0, 0);
ErrorMessage::FileLocation loc2(filename, 0, 0);
locationList.push_back(loc2);
locationList.push_back(loc);
}
ErrorMessage errmsg(locationList,
mTokenizer.list.getSourceFilePath(),
tokenizer.list.getSourceFilePath(),
Severity::error,
e.errorMessage,
e.id,

3
lib/preprocessor.h
View File

@ -91,6 +91,9 @@ public:
void inlineSuppressions(const simplecpp::TokenList &tokens);
void setDirectives(const simplecpp::TokenList &tokens);
void setDirectives(const std::list<Directive> &directives) {
mDirectives = directives;
}
/** list of all directives met while preprocessing file */
const std::list<Directive> &getDirectives() const {

4
lib/tokenize.cpp
View File

@ -157,8 +157,9 @@ Tokenizer::Tokenizer() :
mCodeWithTemplates(false), //is there any templates?
mTimerResults(nullptr)
#ifdef MAXTIME
,mMaxTime(std::time(0) + MAXTIME)
, mMaxTime(std::time(0) + MAXTIME)
#endif
, mPreprocessor(nullptr)
{
}
@ -175,6 +176,7 @@ Tokenizer::Tokenizer(const Settings *settings, ErrorLogger *errorLogger) :
#ifdef MAXTIME
,mMaxTime(std::time(0) + MAXTIME)
#endif
, mPreprocessor(nullptr)
{
// make sure settings are specified
assert(mSettings);

10
lib/tokenize.h
View File

@ -37,6 +37,7 @@ class TimerResults;
class Token;
class TemplateSimplifier;
class ErrorLogger;
class Preprocessor;
namespace simplecpp {
class TokenList;
@ -560,6 +561,13 @@ public:
*/
static const Token * isFunctionHead(const Token *tok, const std::string &endsWith, bool cpp);
void setPreprocessor(const Preprocessor *preprocessor) {
mPreprocessor = preprocessor;
}
const Preprocessor *getPreprocessor() const {
return mPreprocessor;
}
private:
/**
@ -956,6 +964,8 @@ private:
/** Tokenizer maxtime */
const std::time_t mMaxTime;
#endif
const Preprocessor *mPreprocessor;
};
/// @}

16
test/testunusedvar.cpp
View File

@ -17,6 +17,7 @@
*/
#include "checkunusedvar.h"
#include "preprocessor.h"
#include "settings.h"
#include "testsuite.h"
#include "tokenize.h"
@ -55,6 +56,7 @@ private:
TEST_CASE(structmember12); // #7179 - FP unused structmember
TEST_CASE(structmember13); // #3088 - __attribute__((packed))
TEST_CASE(structmember14); // #6508 - (struct x){1,2,..}
TEST_CASE(structmember15); // #3088 - #pragma pack(1)
TEST_CASE(structmember_sizeof);
TEST_CASE(localvar1);
@ -211,12 +213,17 @@ private:
TEST_CASE(volatileData); // #9280
}
void checkStructMemberUsage(const char code[]) {
void checkStructMemberUsage(const char code[], const std::list<Directive> *directives=nullptr) {
// Clear the error buffer..
errout.str("");
Preprocessor preprocessor(settings, nullptr);
if (directives)
preprocessor.setDirectives(*directives);
// Tokenize..
Tokenizer tokenizer(&settings, this);
tokenizer.setPreprocessor(&preprocessor);
std::istringstream istr(code);
tokenizer.tokenize(istr, "test.cpp");
@ -473,6 +480,13 @@ private:
ASSERT_EQUALS("", errout.str());
}
void structmember15() { // #3088
std::list<Directive> directives;
directives.emplace_back("test.cpp", 1, "#pragma pack(1)");
checkStructMemberUsage("\nstruct Foo { int x; int y; };", &directives);
ASSERT_EQUALS("", errout.str());
}
void structmember_extern() {
// extern struct => no false positive
checkStructMemberUsage("extern struct AB\n"