[compiler-rt] [sanitizer] Remove GetCurrentThread nullness checks from Allocate (PR #102828)

[Fangrui Song via llvm-commits]

https://github.com/MaskRay created https://github.com/llvm/llvm-project/pull/102828

The `*Allocate` functions must be called after `*_current_thread` is
set. Delete the nullness checks.

Make this change for asan/msan and possibly extend the change to other
sanitizers. (asan supports many platforms and I am not 100% certain that
all platforms have the property.)


>From e26661aad9ad09ea9304bc483446463a318e4541 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Sun, 11 Aug 2024 13:42:29 -0700
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Created using spr 1.3.5-bogner
---
 compiler-rt/lib/asan/asan_allocator.cpp | 11 ++---------
 compiler-rt/lib/msan/msan_allocator.cpp | 11 ++---------
 2 files changed, 4 insertions(+), 18 deletions(-)

diff --git a/compiler-rt/lib/asan/asan_allocator.cpp b/compiler-rt/lib/asan/asan_allocator.cpp
index 9e66f77217ec6b..e041861edaf0b7 100644
--- a/compiler-rt/lib/asan/asan_allocator.cpp
+++ b/compiler-rt/lib/asan/asan_allocator.cpp
@@ -576,15 +576,8 @@ struct Allocator {
     }
 
     AsanThread *t = GetCurrentThread();
-    void *allocated;
-    if (t) {
-      AllocatorCache *cache = GetAllocatorCache(&t->malloc_storage());
-      allocated = allocator.Allocate(cache, needed_size, 8);
-    } else {
-      SpinMutexLock l(&fallback_mutex);
-      AllocatorCache *cache = &fallback_allocator_cache;
-      allocated = allocator.Allocate(cache, needed_size, 8);
-    }
+    void *allocated = allocator.Allocate(
+        GetAllocatorCache(&t->malloc_storage()), needed_size, 8);
     if (UNLIKELY(!allocated)) {
       SetAllocatorOutOfMemory();
       if (AllocatorMayReturnNull())
diff --git a/compiler-rt/lib/msan/msan_allocator.cpp b/compiler-rt/lib/msan/msan_allocator.cpp
index d7d4967c949859..f478b9979f2daa 100644
--- a/compiler-rt/lib/msan/msan_allocator.cpp
+++ b/compiler-rt/lib/msan/msan_allocator.cpp
@@ -199,15 +199,8 @@ static void *MsanAllocate(BufferedStackTrace *stack, uptr size, uptr alignment,
     ReportRssLimitExceeded(stack);
   }
   MsanThread *t = GetCurrentThread();
-  void *allocated;
-  if (t) {
-    AllocatorCache *cache = GetAllocatorCache(&t->malloc_storage());
-    allocated = allocator.Allocate(cache, size, alignment);
-  } else {
-    SpinMutexLock l(&fallback_mutex);
-    AllocatorCache *cache = &fallback_allocator_cache;
-    allocated = allocator.Allocate(cache, size, alignment);
-  }
+  void *allocated = allocator.Allocate(GetAllocatorCache(&t->malloc_storage()),
+                                       size, alignment);
   if (UNLIKELY(!allocated)) {
     SetAllocatorOutOfMemory();
     if (AllocatorMayReturnNull())