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...of the "-march" options either specified by Chrome OS or crc32c build has to lose the race as there was no other way to specify crc+crypto additively. Is this not deterministic? I would assume either Chrome OS always wins or crc32c always wins. Tell me if I'm wrong. Thanks, David Spickett. ________________________________ From: Manoj Gupta <manojgupta at google.com> Sent: 10 April 2019 17:15:00 To: David Spickett Cc: cfe-dev at lists.llvm.org; llvm-dev at lists.llvm.org; nd; Peter Smith Subject: Re: [llvm-dev] [RFC] New Clang target selection options for ARM/AArch64 On We...

...he same changes be applied to other targets? * could there be future situations where a target would need case specific directives? * Where should this behaviour (whatever it ends up as) be documented? I found [4] but it's more about extensions than the assembler as such. Thanks, David Spickett. [0] https://bugs.llvm.org/show_bug.cgi?id=39527 [1] https://reviews.llvm.org/D72686 [2] https://reviews.llvm.org/D73469 [3] https://reviews.llvm.org/D72923 [4] https://llvm.org/docs/Extensions.html LLVM Extensions — LLVM 10 documentation<https://llvm.org/docs/Extensions.html> SHT_LLVM_ADDRS...

...Are there examples of this kind of build setup that are available publicly? I think I understand the problem but it'd help to see one in action. To see if there are any other Arm extensions that are already being added like this and whether those systems support GCC and how. Thanks, David Spickett. ________________________________ From: Manoj Gupta <manojgupta at google.com> Sent: 10 April 2019 16:34:16 To: David Spickett Cc: cfe-dev at lists.llvm.org; llvm-dev at lists.llvm.org; nd Subject: Re: [llvm-dev] [RFC] New Clang target selection options for ARM/AArch64 On Fri, Sep 21, 201...

cmake -G Ninja -DLLVM_ENABLE_PROJECTS="debuginfo-tests" -DLLVM_USE_LINKER=lld -DCMAKE_BUILD_TYPE="Release" -DLLVM_TARGETS_TO_BUILD=X86 -Wno-dev ../llvm &> ../../cmake.log in cmake.log -- Targeting X86 CMake Error at /home/nnelson/Documents/llvm-project/debuginfo-tests/CMakeLists.txt:30 (message):   Cannot run debuginfo-tests without python 3 installed python3

...for this reason. The linker could always suppress such packing for STO_TAGGED symbols. > > In any case, since all sizes and alignments are known, the compiler should be allowed to emit RELATIVE in the rounded-up array case. > >> >> >> On Fri, Sep 18, 2020 at 4:10 AM David Spickett <david.spickett at linaro.org> wrote: >>> >>> Hi Mitch, >>> >>> In the intro you say: >>> > It would also allow attackers with a semilinear RW primitive to trivially attack global variables if the offset is controllable. Dynamic global tags are...

...be relatively scarce, and coming up with a more complex scheme for the linker to optimise this edge case where it's in bounds of the granule padding (but not the symbol itself) seems over-the-top. In saying that, it's a possibility for later revisions. On Fri, Sep 18, 2020 at 4:10 AM David Spickett <david.spickett at linaro.org> wrote: > Hi Mitch, > > In the intro you say: > > It would also allow attackers with a semilinear RW primitive to > trivially attack global variables if the offset is controllable. Dynamic > global tags are required to provide the same MTE m...

...I've addressed your points below. The overall summary is: - Start with converting the TargetParser to tableGen, with no user facing changes - Add warnings based on that, behind -Wall. Starting with command lines, since directives have larger implications that need investigation Thanks, David Spickett. mandatory features ================== >> Could you go into a bit more detail about mandatory features? I'm pretty sure people are using the extension functionality to turn off features which are technically mandatory according to the reference manual, like floating-point in armv8a....

...g changes we'd like to make to Clang/LLVM to improve the usability of the target options for ARM and AArch64. To keep things simple the proposed changes are listed at the start and you can find the supporting examples at the end of the document. I look forward to your feedback. Thanks, David Spickett. RFC New Clang target feature selection options for ARM/AArch64 -------------------------------------------------------------- In this RFC we propose changes to ARM and AArch64 target selection. With the top level goals to: - validate that given options make sense within architectural restricti...

When I pass an empty string for cpu and features to createTargetMachine, and then use LLVMGetTargetMachineCPU() and LLVMGetTargetMachineFeatureString() to get the strings back, they are still empty. Is there a way to have llvm compute the effective cpu/features string, and provide it so that I can inspect it? I'm trying to figure out how the cpu/features string that I am explicitly passing,

Hi folks, ARM v8.5 introduces the Memory Tagging Extension (MTE), a hardware that allows for detection of memory safety bugs (buffer overflows, use-after-free, etc) with low overhead. So far, MTE support is implemented in the Scudo hardened allocator (compiler-rt/lib/scudo/standalone) for heap, and stack allocation is implemented in LLVM/Clang behind -fsanitize=memtag