Integer Overflow: Don't warn about left-shift expressions with negative result like '1<<31'. That is common practice.
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@ -113,7 +113,7 @@ void CheckType::tooBigBitwiseShiftError(const Token *tok, int lhsbits, const Val
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void CheckType::checkIntegerOverflow()
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{
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// unknown sizeof(int) => can't run this checker
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if (_settings->platformType == Settings::Unspecified)
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if (_settings->platformType == Settings::Unspecified || _settings->int_bit >= 64)
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return;
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// max int value according to platform settings.
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@ -136,7 +136,13 @@ void CheckType::checkIntegerOverflow()
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const ValueFlow::Value *value = tok->getValueGE(maxint + 1, _settings);
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if (!value)
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value = tok->getValueLE(-maxint - 2, _settings);
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if (value)
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if (!value)
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continue;
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// For left shift, it's common practice to shift into the sign bit
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if (tok->str() == "<<" && value->intvalue > 0 && value->intvalue < (1LL << _settings->int_bit))
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continue;
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integerOverflowError(tok, *value);
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}
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}
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@ -42,7 +42,7 @@ private:
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TEST_CASE(checkFloatToIntegerOverflow);
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}
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void check(const char code[], Settings* settings = 0) {
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void check(const char code[], Settings* settings = 0, const char filename[] = "test.cpp") {
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// Clear the error buffer..
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errout.str("");
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@ -55,7 +55,7 @@ private:
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// Tokenize..
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Tokenizer tokenizer(settings, this);
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std::istringstream istr(code);
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tokenizer.tokenize(istr, "test.cpp");
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tokenizer.tokenize(istr, filename);
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// Check..
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CheckType checkType(&tokenizer, settings, this);
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@ -137,6 +137,11 @@ private:
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" return 123456U * x;\n"
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"}",&settings);
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ASSERT_EQUALS("", errout.str());
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check("int foo() {\n"
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" x = 1 << 31;\n" // this is technically integer overflow but it's common code
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"}", &settings, "test.c");
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ASSERT_EQUALS("", errout.str());
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}
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void signConversion() {
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