[asan] Port asan_malloc_linux.cc to RTEMS

[waltl]

Summary

We reuse the allocation interceptors as is. RTEMS doesn't support
dlsyms. However, it needs to handle memory allocation requests before
the ASan run-time has been initialized. We use the dlsym alloc pool
for this purpose, and we increase its size to 4k to support this
usage.

[kcc]

LGTM

compiler-rt/trunk/lib/asan/asan_malloc_linux.cc

 //
 // Linux-specific malloc interception.
 // We simply define functions like malloc, free, realloc, etc.
 // They will replace the corresponding libc functions automagically.
 //===----------------------------------------------------------------------===//
 
 #include "sanitizer_common/sanitizer_platform.h"
 #if SANITIZER_FREEBSD || SANITIZER_FUCHSIA || SANITIZER_LINUX || \
-    SANITIZER_NETBSD || SANITIZER_SOLARIS
+    SANITIZER_NETBSD || SANITIZER_RTEMS || SANITIZER_SOLARIS
 
 #include "sanitizer_common/sanitizer_tls_get_addr.h"
 #include "asan_allocator.h"
 #include "asan_interceptors.h"
 #include "asan_internal.h"
 #include "asan_stack.h"
 
 // ---------------------- Replacement functions ---------------- {{{1
 using namespace __asan;  // NOLINT
 
 static uptr allocated_for_dlsym;
-static const uptr kDlsymAllocPoolSize = 1024;
+static const uptr kDlsymAllocPoolSize = SANITIZER_RTEMS ? 4096 : 1024;
 static uptr alloc_memory_for_dlsym[kDlsymAllocPoolSize];
 
 static INLINE bool IsInDlsymAllocPool(const void *ptr) {
   uptr off = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
   return off < allocated_for_dlsym * sizeof(alloc_memory_for_dlsym[0]);
 }
 
 static void *AllocateFromLocalPool(uptr size_in_bytes) {
   uptr size_in_words = RoundUpTo(size_in_bytes, kWordSize) / kWordSize;
   void *mem = (void*)&alloc_memory_for_dlsym[allocated_for_dlsym];
   allocated_for_dlsym += size_in_words;
   CHECK_LT(allocated_for_dlsym, kDlsymAllocPoolSize);
   return mem;
 }
 
+// On RTEMS, we use the local pool to handle memory allocation before
+// the ASan run-time has been initialized.
+static INLINE bool EarlyMalloc() {
+  return SANITIZER_RTEMS && (!asan_inited || asan_init_is_running);
+}
+
 static INLINE bool MaybeInDlsym() {
   // Fuchsia doesn't use dlsym-based interceptors.
   return !SANITIZER_FUCHSIA && asan_init_is_running;
 }
 
+static INLINE bool UseLocalPool() {
+  return EarlyMalloc() || MaybeInDlsym();
+}
+
 static void *ReallocFromLocalPool(void *ptr, uptr size) {
   const uptr offset = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
   const uptr copy_size = Min(size, kDlsymAllocPoolSize - offset);
   void *new_ptr;
-  if (UNLIKELY(MaybeInDlsym())) {
+  if (UNLIKELY(UseLocalPool())) {
     new_ptr = AllocateFromLocalPool(size);
   } else {
     ENSURE_ASAN_INITED();
     GET_STACK_TRACE_MALLOC;
     new_ptr = asan_malloc(size, &stack);
   }
   internal_memcpy(new_ptr, ptr, copy_size);
   return new_ptr;
INTERCEPTOR(void, cfree, void *ptr) {
   GET_STACK_TRACE_FREE;
   if (UNLIKELY(IsInDlsymAllocPool(ptr)))
     return;
   asan_free(ptr, &stack, FROM_MALLOC);
 }
 #endif // SANITIZER_INTERCEPT_CFREE
 
 INTERCEPTOR(void*, malloc, uptr size) {
-  if (UNLIKELY(MaybeInDlsym()))
+  if (UNLIKELY(UseLocalPool()))
     // Hack: dlsym calls malloc before REAL(malloc) is retrieved from dlsym.
     return AllocateFromLocalPool(size);
   ENSURE_ASAN_INITED();
   GET_STACK_TRACE_MALLOC;
   return asan_malloc(size, &stack);
 }
 
 INTERCEPTOR(void*, calloc, uptr nmemb, uptr size) {
-  if (UNLIKELY(MaybeInDlsym()))
+  if (UNLIKELY(UseLocalPool()))
     // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
     return AllocateFromLocalPool(nmemb * size);
   ENSURE_ASAN_INITED();
   GET_STACK_TRACE_MALLOC;
   return asan_calloc(nmemb, size, &stack);
 }
 
 INTERCEPTOR(void*, realloc, void *ptr, uptr size) {
   if (UNLIKELY(IsInDlsymAllocPool(ptr)))
     return ReallocFromLocalPool(ptr, size);
-  if (UNLIKELY(MaybeInDlsym()))
+  if (UNLIKELY(UseLocalPool()))
     return AllocateFromLocalPool(size);
   ENSURE_ASAN_INITED();
   GET_STACK_TRACE_MALLOC;
   return asan_realloc(ptr, size, &stack);
 }
 
 #if SANITIZER_INTERCEPT_MEMALIGN
 INTERCEPTOR(void*, memalign, uptr boundary, uptr size) {