84 lines
1.9 KiB
Markdown
84 lines
1.9 KiB
Markdown
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# Speeding up Cppcheck
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It is possible to speed up Cppcheck analysis in a few different ways.
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## Preprocessor configurations
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Imagine this source code:
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void foo()
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{
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int x;
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#ifdef __GNUC__
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x = 0;
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#endif
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#ifdef _MSC_VER
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x = 1;
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#endif
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return x;
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}
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By default Cppcheck will try to check all the configurations. There are 3 important configurations here:
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- Neither `__GNUC__` nor `_MSC_VER` is defined
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- `__GNUC__` is defined
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- `_MSC_VER` is defined
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When you run Cppcheck, the output will be something like:
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$ cppcheck test.c
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Checking test.c ...
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[test.c:10]: (error) Uninitialized variable: x
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Checking test.c: __GNUC__...
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Checking test.c: _MSC_VER...
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Now if you want you can limit the analysis. You probably know what the target compiler is. If `-D` is supplied and you do not specify `--force` then Cppcheck will only check the configuration you give.
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$ cppcheck -D __GNUC__ test.c
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Checking test.c ...
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Checking test.c: __GNUC__=1...
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## Unused templates
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If you think Cppcheck is slow and you are using templates, then you should try how it works to remove unused templates.
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Imagine this code:
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template <class T> struct Foo {
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T x = 100;
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};
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template <class T> struct Bar {
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T x = 200 / 0;
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};
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int main() {
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Foo<int> foo;
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return 0;
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}
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Cppcheck says:
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$ cppcheck test.cpp
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Checking test.cpp ...
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[test.cpp:7]: (error) Division by zero.
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It complains about division by zero in `Bar` even though `Bar` is not instantiated.
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You can use the option `--remove-unused-templates` to remove unused templates from Cppcheck analysis.
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Example:
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$ cppcheck --remove-unused-templates test.cpp
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Checking test.cpp ...
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This lost message is in theory not critical, since `Bar` is not instantiated the division by zero should not occur in your real program.
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The speedup you get can be remarkable.
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## Check headers
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TBD
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