More warnings

[NOhs]

I think the following flags should be added to the defaults:

-fsanitize=address

see https://clang.llvm.org/docs/AddressSanitizer.html

and also

-Wshadow

seem useful flags for writing clean code. The first one can help identify illegal access mistakes and the second one can help finding shadowing bugs like in e.g. nested loops where the loop variables are shadowed in one of the inner loops.

[GPMueller]

Agreed!
But isn't -Wshadow automatically added by -Wall? Or does that not actually add "all" warnings?

[GPMueller]

Should behave the same as in gcc, so according to https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html -Wshadow is not activated by -Wall or -Wextra.

We should maybe also add -Wpedantic. People who do not want to be ISO-conformant should probably manually set all their flags.

And what about -fsanitize=leak and -fsanitize=undefined, see https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options

[NOhs]

I agree to add all your suggestions.

[GPMueller]

Unfortunately

• -fsanitize=leak won't work, except on OSX: clang++.EXE: error: unsupported option '-fsanitize=leak' for target 'x86_64-pc-windows-msvc'
• it seems -fsanitize=address and -fsanitize=undefined should be also passed to the linker, but not for static libraries

See also http://clang.llvm.org/docs/AddressSanitizer.html#platforms and http://clang.llvm.org/docs/LeakSanitizer.html

[GPMueller]

As the documentation (address, undefined behaviour) states, there is no run-time performance impact of ubsan, but asan gives a ~2x slowdown.
Should we

• add sanitizers to the default debug flags (also increase optimisation to Og and add -fno-optimize-sibling-calls -fno-omit-frame-pointer)?
• create a new sanitize build type?

[GPMueller]

I decided to add sanitizers directly to the debug build on PR #99. This can easily be changed later, if we feel that there should be a separate build type.