Predefine version FreeStanding when targeting bare-metal
#3608
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| @@ -2,13 +2,16 @@ | |||
| // RUN: %ldc -mtriple=x86_64 -c -w %s | |||
| // RUN: not %ldc -mtriple=x86_64 -c -w -d-version=WithSynchronized %s 2>&1 | FileCheck %s | |||
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hm, I always thought that specifying a triple without the 2nd/3rd parts would select the default for the host OS, instead of selecting "no OS"....
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See Clang's documentation https://clang.llvm.org/docs/CrossCompilation.html#target-triple
Clang also uses the default when a triple part is empty, instead of assuming none.
-ffreestanding is what we should implement, in my opinion.
See also: https://chromium.googlesource.com/external/llvm.org/clang/+/google/stable/test/CodeGen/PR3589-freestanding-libcalls.c
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Clang also uses the default when a triple part is empty, instead of assuming
none.
Doesn't seem to be the case: https://cpp.godbolt.org/z/ThW5jW. I think -march=x86-64 is to be used when only wanting to target another arch, with the same host OS and environment.
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Ah OK. Indeed.
I presume FreeStanding can be used to disable all parts of druntime that depend on a host OS. So it'd be good to be able to still set the arch without changing OS.
Is LDCs behavior changed now? (e.g. that before -mtriple=x86_64 would still compile-in all Linux/Windows/... parts.)
Don't think so right?
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Nothing has changed (FreeStanding isn't used anywhere in druntime/Phobos yet); Windows, linux, OSX etc. haven't been predefined before either. I think it just might make disabling parts you've mentioned easier.
| void foo() {} | ||
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| version (WithSynchronized) | ||
| void bar() | ||
| { | ||
| __gshared int global; | ||
| // CHECK: unknown_critical_section_size.d(12): Error: unknown critical section size for the selected target |
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fyi, FileCheck has @LINE for such cases: ...size.d([[@LINE+1]]): Error...
http://llvm.org/docs/CommandGuide/FileCheck.html#filecheck-pseudo-numeric-variables
Resolves #3607.
This has been added 5+ years ago with dlang/dlang.org@4c9a20a.