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76 lines
2.7 KiB
C
76 lines
2.7 KiB
C
#ifndef COSMOPOLITAN_LIBC_ASSERT_H_
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#define COSMOPOLITAN_LIBC_ASSERT_H_
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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COSMOPOLITAN_C_START_
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extern bool __assert_disable;
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void __assert_fail(const char *, const char *, int) _Hide relegated;
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#ifdef NDEBUG
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#define assert(x) ((void)0)
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#else
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#define assert(x) ((void)((x) || (__assert_fail(#x, __FILE__, __LINE__), 0)))
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#endif
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#ifndef __cplusplus
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#define static_assert _Static_assert
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#endif
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#ifdef __GNUC__
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#if !defined(TINY) && !defined(MODE_DBG)
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/**
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* Specifies expression can't possibly be false.
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*
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* This macro uses the `notpossible` keyword and is intended for things
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* like systems integration, where we know for a fact that something is
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* never going to happen, but there's no proof. So we don't want to add
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* extra bloat for filenames and line numbers, since `ShowCrashReports`
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* can print a backtrace if we just embed the UD2 instruction to crash.
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* That's useful for systems code, for the following reason. Invariants
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* make sense with _unassert() since they usually get placed at the top
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* of functions. But if you used _unassert() to test a system call does
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* not fail, then check happens at the end of your function usually and
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* is therefore likely to result in a failure condition where execution
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* falls through into a different function, which is shocking to debug.
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*
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* In `MODE=tiny` these assertions are redefined as undefined behavior.
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*/
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#define _npassert(x) \
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({ \
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if (__builtin_expect(!(x), 0)) { \
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notpossible; \
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} \
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(void)0; \
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})
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#else
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#define _npassert(x) _unassert(x)
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#endif
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#endif
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#ifdef __GNUC__
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/**
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* Specifies expression being false is undefined behavior.
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*
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* This is a good way to tell the compiler about your invariants, which
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* leads to smaller faster programs. The expression is never removed by
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* the preprocessor so it's recommended that it be free of side-effects
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* if you intend for it to be removed. At the same time, this guarantee
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* makes this assertion useful for things like system calls, since they
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* won't be removed by `NDEBUG` mode.
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*
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* If this assertion fails, the worst possible things can happen unless
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* you've built your binary in `MODE=dbg` since UBSAN is the only thing
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* that's capable of debugging this macro.
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*/
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#define _unassert(x) \
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({ \
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if (__builtin_expect(!(x), 0)) { \
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unreachable; \
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} \
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(void)0; \
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})
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#endif
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COSMOPOLITAN_C_END_
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_ASSERT_H_ */
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