[PATCH] D83494: [libFuzzer] Link libFuzzer's own interceptors when other compiler runtimes are not linked.

[Matt Morehouse via Phabricator via cfe-commits]

morehouse added inline comments.


================
Comment at: compiler-rt/lib/fuzzer/FuzzerInterceptors.cpp:62
+
+static int internal_strncmp(const char *s1, const char *s2, uintptr_t n) {
+  for (uintptr_t i = 0; i < n; i++) {
----------------
Can we use `size_t` instead of `uintptr_t`?


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Comment at: compiler-rt/lib/fuzzer/FuzzerInterceptors.cpp:77
+static int internal_memcmp(const void *s1, const void *s2, uintptr_t n) {
+  const char *t1 = (const char *)s1;
+  const char *t2 = (const char *)s2;
----------------
Can we use `uint8_t` and `static_cast`?


================
Comment at: compiler-rt/lib/fuzzer/FuzzerInterceptors.cpp:119
+    return internal_memcmp(s1, s2, n);
+  ensureFuzzerInited();
+  int result = REAL(memcmp)(s1, s2, n);
----------------
I think `ensureFuzzerInited` is no longer useful here.


================
Comment at: compiler-rt/test/fuzzer/CustomAllocatorTest.cpp:15
+  return 0;
+}
----------------
Do we need this file?  Can we use `EmptyTest.cpp` instead?


================
Comment at: compiler-rt/test/fuzzer/custom-allocator.test:2
+UNSUPPORTED: freebsd
+RUN: %cpp_compiler -fno-sanitize=all -fno-builtin %S/CustomAllocator.cpp -fPIC %ld_flags_rpath_so1 -O0 -shared -o %dynamiclib1
+RUN: %cpp_compiler -fno-sanitize=address %S/CustomAllocatorTest.cpp %ld_flags_rpath_exe1 -o %t-NoAsanCustomAllocatorTest
----------------
Why do we need each of these flags?


================
Comment at: compiler-rt/test/fuzzer/memcmp.test:9
+RUN: %cpp_compiler -fno-sanitize=all -fno-builtin %S/CustomAllocator.cpp -fPIC %ld_flags_rpath_so1 -O0 -shared -o %dynamiclib1
+RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-memcmp %S/MemcmpTest.cpp %ld_flags_rpath_exe1 -o %t-NoAsanCustomAllocatorMemcmpTest
+RUN: not %run %t-NoAsanCustomAllocatorMemcmpTest        -seed=1 -runs=10000000   2>&1 | FileCheck %s
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Why is the custom allocator test here useful?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D83494/new/

https://reviews.llvm.org/D83494