[ATfE] Enable minimal libc++ testing with LLVM libc - #953
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This adds one AArch64 and two Armv7-M (softfp and hardfp) configurations to test libc++ on top on LLVM libc. This requires some small changes/fixes along the way: - JSON files enable tests and also provide enough memory for C++ tests. - CMake and lit option to tell which C library is used for C++ tests. - CMake disable unused rt library. - Test runners to only pass the name of the test binary - not full paths that exceeds LLVM libc bootcode limit and is not used anyway. - Enable stderr to be used separately from stdout in LLVM semihosting and FVP parameters. The resulting failures added to the xfail list: mostly missing functionality or mismatch with hosted behavior. A few stdin tests excluded since they hang with semihosting thus trigger the long timeout.
vhscampos
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Aug 17, 2026
| -DLIBCXX_ENABLE_FILESYSTEM=OFF | ||
| -DLIBCXX_ENABLE_LOCALIZATION=ON | ||
| -DLIBCXX_ENABLE_UNICODE=OFF | ||
| -DLIBCXX_HAS_RT_LIB=OFF |
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Can you explain in the PR description why the rt lib needs to be disabled?
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Yes, expanded: it effectively controls use of clock_gettime() that is a POSIX function provided by bare-metal LLVM libc now (it seems to be provided for some other targets though).
| stdio_open(&__llvm_libc_stdin_cookie, OPENMODE_R); | ||
| stdio_open(&__llvm_libc_stdout_cookie, OPENMODE_W); | ||
| stdio_open(&__llvm_libc_stderr_cookie, OPENMODE_W); | ||
| stdio_open(&__llvm_libc_stderr_cookie, OPENMODE_A); |
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Expanded the description as well: this is how the stderr is opened (vs stdout).
vhscampos
approved these changes
Aug 17, 2026
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This adds one AArch64 and two Armv7-M (softfp and hardfp) configurations to test libc++ on top on LLVM libc.
This requires some small changes/fixes along the way:
The resulting failures added to the xfail list: mostly missing functionality or mismatch with hosted behavior. A few stdin tests excluded since they hang with semihosting thus trigger the long timeout.