[compiler-rt][cmake] Test COMPILER_RT_HAS_AARCH64_SME with arm64 #141115
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architecture only. Apple configures CMake only once for compiler-rt, even when building for multiple architectures. As a result, we need to explicitly test for arm64 specific attributes by building for that architecture rdar://149068965
| " | ||
| void foo(void) __arm_streaming_compatible { | ||
| asm(\".arch armv9-a+sme2\\n\" | ||
| \"smstart\\n\" | ||
| \"ldr zt0, [sp]\"); | ||
| } | ||
| ") | ||
| " "-target aarch64-linux-gnu") |
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Do we document somewhere which compilers are supported to build compiler-rt? If we support non-clang compilers, this test won't work on such compilers. (And if we don't support non-clang compilers, why are we checking this?)
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This SME test is to check the clang being used is new enough to support compiling the builtins for SME.
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So you're saying the only supported compiler is clang? What versions of clang?
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The idea of this test is to check if the clang version is new enough in terms of features that it doesn't barf when given SME2 constructs and the keyword attributes __arm_streaming_compatible. It doesn't need to check for a specific clang version.
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We don't need to hardcode versions here, but we need to have some idea, in general, of what compilers we support. Like, are we going to add code to support clang 3.0? Probably not, but have we written that down anywhere?
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I was under the impression that LLVM_ENABLE_PROJECTS wasn't supposed to be used anymore for compiler-rt and it was only a matter of time before support is removed completely. On that basis it seems the expectation is that eventually they become rev-locked. At which point some of these tests will become redundant except for ones check a particular target has been built.
And yes, I know that's a self-incriminating statement. I believe we are trying to move to LLVM_ENABLE_RUNTIMES but software is hard.
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The removal from LLVM_ENABLE_PROJECTS doesn't necessarily imply anything about the compiler; even in a "runtimes" build you can point to any compiler you want.
libcxx has a specific policy around this.
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Ok, that's not what I thought it meant. @petrhosek your slides at https://llvm.org/devmtg/2023-10/slides/tutorials/Hosek-UnderstandingtheLLVMbuild.pdf on slide 18 indicate that RUNTIMES mean using the just-built compiler. Is that not strictly true?
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LLVM_ENABLE_RUNTIMES is always the just-built compiler, yes. But a "runtimes" build can also just invoked directly (see https://libcxx.llvm.org/VendorDocumentation.html#the-default-build ).
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Err, I mean, passing LLVM_ENABLE_RUNTIMES to an LLVM build always uses the LLVM_ENABLE_RUNTIMES. I guess the option for choosing which runtimes are enabled if you directly invoke the runtimes build is also named LLVM_ENABLE_RUNTIMES .
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/64/builds/3749 Here is the relevant piece of the build log for the reference |
…m#141115) architecture only. Apple configures CMake only once for compiler-rt, even when building for multiple architectures. As a result, we need to explicitly test for arm64 specific attributes by building for that architecture
llvm#141280) …m64 (llvm#141115)" This reverts commit a2ce564.
…m#141115) architecture only. Apple configures CMake only once for compiler-rt, even when building for multiple architectures. As a result, we need to explicitly test for arm64 specific attributes by building for that architecture
architecture only.
Apple configures CMake only once for compiler-rt, even when building for multiple architectures. As a result, we need to explicitly test for arm64 specific attributes by building for that architecture