[HWASan] Use hwasan_memalign for aligned new.

[vitalybuka]

Summary

Aligned new does not require size to be a multiple of alignment, so
memalign is the correct choice instead of aligned_alloc.

Fixes false reports for unaligned sizes.

[eugenis]

LGTM

[thakis]

This doesn't build on our bots: https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket/8822637711003001489/+/u/package_clang/stdout?format=raw

 : 'RUN: at line 2';      /b/s/w/ir/cache/builder/src/third_party/llvm-build/Release+Asserts/./bin/clang  --driver-mode=g++  -m64  -gline-tables-only -fsanitize=hwaddress -fuse-ld=lld -fsanitize-hwaddress-experimental-aliasing -mllvm -hwasan-generate-tags-with-calls=1 -mllvm -hwasan-globals -mllvm -hwasan-use-short-granules -mllvm -hwasan-instrument-landing-pads=0 -mllvm -hwasan-instrument-personality-functions -std=c++17 /b/s/w/ir/cache/builder/src/third_party/llvm/compiler-rt/test/hwasan/TestCases/new-test.cpp -o /b/s/w/ir/cache/builder/src/third_party/llvm-build/Release+Asserts/projects/compiler-rt/test/hwasan/X86_64/TestCases/Output/new-test.cpp.tmp
[...]
 Command Output (stderr):
 --
 /b/s/w/ir/cache/builder/src/third_party/llvm/compiler-rt/test/hwasan/TestCases/new-test.cpp:22:32: error: no member named 'align_val_t' in namespace 'std'
   constexpr auto kAlign = std::align_val_t{8};
                           ~~~~~^
 /b/s/w/ir/cache/builder/src/third_party/llvm/compiler-rt/test/hwasan/TestCases/new-test.cpp:22:43: error: expected ';' at end of declaration
   constexpr auto kAlign = std::align_val_t{8};
                                           ^
                                           ;
 2 errors generated.

The problem is probably that system gcc on that bot is fairly old. So we have gcc 10.2 somewhere on the side, and pass '-DCOMPILER_RT_TEST_COMPILER_CFLAGS=--gcc-toolchain=/b/s/w/ir/cache/builder/src/third_party/llvm-build-tools/gcc-10.2.0-trusty -Wl,-rpath,/b/s/w/ir/cache/builder/src/third_party/llvm-build-tools/gcc-10.2.0-trusty/lib64 -Wl,-rpath,/b/s/w/ir/cache/builder/src/third_party/llvm-build-tools/gcc-10.2.0-trusty/lib32' to cmake, but it looks like that doesn't make it into %clangxx_hwasan (?)

[vitalybuka]

compiler-rt/test/hwasan/TestCases/new-test.cpp

5

Maybe just:
// REQUIRES: Clang

[vitalybuka]

compiler-rt/test/hwasan/TestCases/new-test.cpp

5

ignore this
it's already clang, just different std lib

[thakis]

Reverted in a908c535f983bd31ab9346675ff89d34334603aa for now.

[vitalybuka]

Fix test for older glibcxx

[vitalybuka]

rebase

compiler-rt/lib/hwasan/hwasan_new_delete.cpp

 // TODO(alekseys): throw std::bad_alloc instead of dying on OOM.
 #define OPERATOR_NEW_BODY(nothrow) \
   GET_MALLOC_STACK_TRACE; \
   void *res = hwasan_malloc(size, &stack);\
   if (!nothrow && UNLIKELY(!res)) ReportOutOfMemory(size, &stack);\
   return res
 #define OPERATOR_NEW_ALIGN_BODY(nothrow)                                    \
   GET_MALLOC_STACK_TRACE;                                                   \
-  void *res = hwasan_aligned_alloc(static_cast<uptr>(align), size, &stack); \
+  void *res = hwasan_memalign(static_cast<uptr>(align), size, &stack);      \
   if (!nothrow && UNLIKELY(!res))                                           \
     ReportOutOfMemory(size, &stack);                                        \
   return res
 
 #define OPERATOR_DELETE_BODY \
   GET_MALLOC_STACK_TRACE; \
   if (ptr) hwasan_free(ptr, &stack)
 

compiler-rt/test/hwasan/TestCases/new-test.cpp

 // Test basic new functionality.
-// RUN: %clangxx_hwasan %s -o %t
+// RUN: %clangxx_hwasan -std=c++17 %s -o %t
 // RUN: %run %t
 
-#include <stdlib.h>
-#include <assert.h>
-#include <sanitizer/hwasan_interface.h>
+#include <cassert>
+#include <cstdint>
+#include <cstdlib>
+#include <new>
 #include <sanitizer/allocator_interface.h>
+#include <sanitizer/hwasan_interface.h>
 
 int main() {
   __hwasan_enable_allocator_tagging();
 
   size_t volatile n = 0;
   char *a1 = new char[n];
   assert(a1 != nullptr);
   assert(__sanitizer_get_allocated_size(a1) == 0);
   delete[] a1;
+
+  // Aligned new/delete
+  constexpr auto kAlign = std::align_val_t{8};
+  void *a2 = ::operator new(4, kAlign);
+  assert(a2 != nullptr);
+  assert(reinterpret_cast<uintptr_t>(a2) % static_cast<uintptr_t>(kAlign) == 0);
+  assert(__sanitizer_get_allocated_size(a2) >= 4);
+  ::operator delete(a2, kAlign);
 }