[PATCH] D99381: [compiler-rt][hwasan] Add Fuchsia-specific sanitizer platform limits

[Leonard Chan via Phabricator via cfe-commits]

leonardchan added a comment.

In D99381#2651896 <https://reviews.llvm.org/D99381#2651896>, @mcgrathr wrote:

> I don't think this is warranted.  There should not be any references to such things when building for Fuchsia.
> This looks like it's intended to satisfy one reference in dead code in hwasan_interceptors.cpp.
> I think the right solution is just to refactor the hwasan code so that the dead code is not compiled for Fuchsia at all.

To add more context, this patch was meant to resolve this missing type error:

  [27/32] Building CXX object compiler-rt/lib/hwasan/CMakeFiles/RTHwasan_dynamic.aarch64.dir/hwasan.cpp.obj
  FAILED: compiler-rt/lib/hwasan/CMakeFiles/RTHwasan_dynamic.aarch64.dir/hwasan.cpp.obj 
  /usr/local/google/home/leonardchan/llvm-monorepo/llvm-build-4-master-fuchsia-toolchain/./bin/clang++ --target=aarch64-unknown-fuchsia --sysroot=/usr/local/google/home/leonardchan/sdk/garnet/arch/arm64/sysroot -DHWASAN_REPLACE_OPERATORS_NEW_AND_DELETE=1 -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/compiler-rt/lib/hwasan/.. --target=aarch64-unknown-fuchsia -I/usr/local/google/home/leonardchan/sdk/garnet/pkg/fdio/include -fPIC -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -ffunction-sections -fdata-sections -ffile-prefix-map=/usr/local/google/home/leonardchan/llvm-monorepo/llvm-build-4-master-fuchsia-toolchain/runtimes/runtimes-aarch64-unknown-fuchsia-bins=../llvm-build-4-master-fuchsia-toolchain/runtimes/runtimes-aarch64-unknown-fuchsia-bins -ffile-prefix-map=/usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/= -no-canonical-prefixes -Wall -std=c++14 -Wno-unused-parameter -O2 -g -DNDEBUG  -fPIC -fno-builtin -fno-exceptions -fomit-frame-pointer -funwind-tables -fno-stack-protector -fno-sanitize=safe-stack -fvisibility=hidden -fno-lto -O3 -gline-tables-only -Wno-gnu -Wno-variadic-macros -Wno-c99-extensions -nostdinc++ -fno-rtti -fPIC -ffreestanding -ftls-model=initial-exec -MD -MT compiler-rt/lib/hwasan/CMakeFiles/RTHwasan_dynamic.aarch64.dir/hwasan.cpp.obj -MF compiler-rt/lib/hwasan/CMakeFiles/RTHwasan_dynamic.aarch64.dir/hwasan.cpp.obj.d -o compiler-rt/lib/hwasan/CMakeFiles/RTHwasan_dynamic.aarch64.dir/hwasan.cpp.obj -c /usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/compiler-rt/lib/hwasan/hwasan.cpp
  In file included from /usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/compiler-rt/lib/hwasan/hwasan.cpp:14:
  In file included from /usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/compiler-rt/lib/hwasan/hwasan.h:20:
  /usr/local/google/home/leonardchan/llvm-monorepo/llvm-project-4/compiler-rt/lib/hwasan/hwasan_interface_internal.h:204:11: error: no type named '__sanitizer_struct_mallinfo' in namespace '__hwasan'
  __hwasan::__sanitizer_struct_mallinfo __sanitizer_mallinfo();
  ~~~~~~~~~~^

`__sanitizer_struct_mallinfo` is used as part of the hwasan interface:

  SANITIZER_INTERFACE_ATTRIBUTE
  __hwasan::__sanitizer_struct_mallinfo __sanitizer_mallinfo();

So I'm thinking unless we want to change the API, we may not want to change or remove this function. The error comes up because `__sanitizer_struct_mallinfo` is currently only defined if `SANITIZER_LINUX || SANITIZER_MAC` is true, so it felt appropriate to add a fuchsia-specific definition in `sanitizer_platform_limits_fuchsia.h` which can just be empty if we don't use it anyway. Would refactoring still be applicable in this case?


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