wasm2c runtime: refactor handling of alternate stack (NFC) #2338
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keithw
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wasm2c/wasm-rt-impl.c
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| stderr, | ||
| "wasm-rt error: tried to re-allocate thread-local alternate stack\n"); | ||
| abort(); | ||
| } |
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I'm not sure what the convention is within this file, but would it make sense to write these 6 lines as assert(!g_alt_stack && "wasm-rt error: tried to re-allocate thread-local alternate stack")?
| #ifndef NDEBUG | ||
| fprintf(stderr, | ||
| "wasm-rt warning: alternate stack was modified unexpectedly\n"); | ||
| #endif |
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And this could just be assert(false && ..?
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I'd rather not make this one abort() on failure, since it seems plausible the application would install its own altstack at some point, and that shouldn't be (in my view) an abort-style fatal error...
The runtime installs an alternate stack to handle SIGSEGV from stack exhaustion. Make this variable thread-local and refactor implementation that touches it.
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| sa.sa_flags = SA_SIGINFO | SA_ONSTACK; | ||
| #endif |
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How about:
sa.sa_flags = SA_SIGINFO;
#if !WASM_RT_USE_STACK_DEPTH_COUNT
sa.sa_flags |= SA_ONSTACK;
#endif
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Split out from #2332.
This makes the
g_alt_stackvariable thread-local and splits out the internal routines that handle allocation/installation. This will make it a smaller change to add the per-thread initialization API in #2332.