[compiler-rt] [NFC] [scudo] Use AllocationRingBuffer* for pointer to ring buffer (PR #82538)

[Florian Mayer via llvm-commits]

https://github.com/fmayer created https://github.com/llvm/llvm-project/pull/82538

This is for consistency of how we store the StackDepot


>From eb10a56ddbe974e41d32c913a994dc89ad39c065 Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer at google.com>
Date: Wed, 21 Feb 2024 13:36:43 -0800
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.4
---
 compiler-rt/lib/scudo/standalone/combined.h | 23 +++++++++------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/compiler-rt/lib/scudo/standalone/combined.h b/compiler-rt/lib/scudo/standalone/combined.h
index 080ba42ad44497..543b5958c71416 100644
--- a/compiler-rt/lib/scudo/standalone/combined.h
+++ b/compiler-rt/lib/scudo/standalone/combined.h
@@ -936,7 +936,7 @@ class Allocator {
 
   const char *getRingBufferAddress() {
     initThreadMaybe();
-    return RawRingBuffer;
+    return reinterpret_cast<char *>(RingBuffer);
   }
 
   uptr getRingBufferSize() {
@@ -1066,7 +1066,7 @@ class Allocator {
   };
   // Pointer to memory mapped area starting with AllocationRingBuffer struct,
   // and immediately followed by Size elements of type Entry.
-  char *RawRingBuffer = {};
+  AllocationRingBuffer *RingBuffer = {};
   u32 RingBufferElements = 0;
   MemMapT RawRingBufferMap;
 
@@ -1275,9 +1275,9 @@ class Allocator {
   void storeRingBufferEntry(void *Ptr, u32 AllocationTrace, u32 AllocationTid,
                             uptr AllocationSize, u32 DeallocationTrace,
                             u32 DeallocationTid) {
-    uptr Pos = atomic_fetch_add(&getRingBuffer()->Pos, 1, memory_order_relaxed);
+    uptr Pos = atomic_fetch_add(&RingBuffer->Pos, 1, memory_order_relaxed);
     typename AllocationRingBuffer::Entry *Entry =
-        getRingBufferEntry(RawRingBuffer, Pos % RingBufferElements);
+        getRingBufferEntry(RingBuffer, Pos % RingBufferElements);
 
     // First invalidate our entry so that we don't attempt to interpret a
     // partially written state in getSecondaryErrorInfo(). The fences below
@@ -1500,12 +1500,14 @@ class Allocator {
   }
 
   static typename AllocationRingBuffer::Entry *
-  getRingBufferEntry(char *RawRingBuffer, uptr N) {
+  getRingBufferEntry(AllocationRingBuffer *RingBuffer, uptr N) {
+    char *RawRingBuffer = reinterpret_cast<char *>(RingBuffer);
     return &reinterpret_cast<typename AllocationRingBuffer::Entry *>(
         &RawRingBuffer[sizeof(AllocationRingBuffer)])[N];
   }
   static const typename AllocationRingBuffer::Entry *
-  getRingBufferEntry(const char *RawRingBuffer, uptr N) {
+  getRingBufferEntry(const AllocationRingBuffer *RingBuffer, uptr N) {
+    const char *RawRingBuffer = reinterpret_cast<const char *>(RingBuffer);
     return &reinterpret_cast<const typename AllocationRingBuffer::Entry *>(
         &RawRingBuffer[sizeof(AllocationRingBuffer)])[N];
   }
@@ -1558,7 +1560,7 @@ class Allocator {
         roundUp(ringBufferSizeInBytes(AllocationRingBufferSize),
                 getPageSizeCached()),
         "scudo:ring_buffer");
-    RawRingBuffer = reinterpret_cast<char *>(MemMap.getBase());
+    RingBuffer = reinterpret_cast<AllocationRingBuffer *>(MemMap.getBase());
     RawRingBufferMap = MemMap;
     RingBufferElements = AllocationRingBufferSize;
     static_assert(sizeof(AllocationRingBuffer) %
@@ -1568,12 +1570,11 @@ class Allocator {
   }
 
   void unmapRingBuffer() {
-    auto *RingBuffer = getRingBuffer();
     if (RingBuffer != nullptr) {
       RawRingBufferMap.unmap(RawRingBufferMap.getBase(),
                              RawRingBufferMap.getCapacity());
     }
-    RawRingBuffer = nullptr;
+    RingBuffer = nullptr;
     if (Depot) {
       RawStackDepotMap.unmap(RawStackDepotMap.getBase(),
                              RawStackDepotMap.getCapacity());
@@ -1592,10 +1593,6 @@ class Allocator {
     return (Bytes - sizeof(AllocationRingBuffer)) /
            sizeof(typename AllocationRingBuffer::Entry);
   }
-
-  inline AllocationRingBuffer *getRingBuffer() {
-    return reinterpret_cast<AllocationRingBuffer *>(RawRingBuffer);
-  }
 };
 
 } // namespace scudo