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nimRawSetjmp: support Windows (#19197)

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* nimRawSetjmp: support Windows

Using `_setjmp()` directly is required to avoid some rare (but very
annoying) exception-related stack corruption leading to segfaults on
Windows, with Mingw-w64 and SEH.
More details: https://github.com/status-im/nimbus-eth2/issues/3121

Also add "nimBuiltinSetjmp" - mostly for benchmarking.

* fix for Apple's Clang++
This commit is contained in:
Ștefan Talpalaru 2021-12-10 06:31:29 +01:00 • committed by GitHub
commit 69aabdab80
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5 changed files with 199 additions and 10 deletions
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13
compiler/ccgstmts.nim
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@ -1356,8 +1356,19 @@ proc genTrySetjmp(p: BProc, t: PNode, d: var TLoc) =
linefmt(p, cpsStmts, "$1.status = setjmp($1.context);$n", [safePoint])
elif isDefined(p.config, "nimSigSetjmp"):
linefmt(p, cpsStmts, "$1.status = sigsetjmp($1.context, 0);$n", [safePoint])
elif isDefined(p.config, "nimBuiltinSetjmp"):
linefmt(p, cpsStmts, "$1.status = __builtin_setjmp($1.context);$n", [safePoint])
elif isDefined(p.config, "nimRawSetjmp"):
linefmt(p, cpsStmts, "$1.status = _setjmp($1.context);$n", [safePoint])
if isDefined(p.config, "mswindows"):
# The Windows `_setjmp()` takes two arguments, with the second being an
# undocumented buffer used by the SEH mechanism for stack unwinding.
# Mingw-w64 has been trying to get it right for years, but it's still
# prone to stack corruption during unwinding, so we disable that by setting
# it to NULL.
# More details: https://github.com/status-im/nimbus-eth2/issues/3121
linefmt(p, cpsStmts, "$1.status = _setjmp($1.context, 0);$n", [safePoint])
else:
linefmt(p, cpsStmts, "$1.status = _setjmp($1.context);$n", [safePoint])
else:
linefmt(p, cpsStmts, "$1.status = setjmp($1.context);$n", [safePoint])
lineCg(p, cpsStmts, "if ($1.status == 0) {$n", [safePoint])