From d0d6fc911c43db48fb0c4332fd64ca3e80c4e3cd Mon Sep 17 00:00:00 2001
From: Austin Eng <enga@chromium.org>
Date: Tue, 25 Apr 2023 21:33:22 +0000
Subject: [PATCH] Return a pointer to a global static for zero-length
 GetMappedRange

Bug: chromium:1430985
Change-Id: Iaca7a21487a5a7e2b41dd9a363a7efd913a0f208
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/129180
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Brendon Tiszka <tiszka@google.com>
---
 src/dawn/native/Buffer.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/dawn/native/Buffer.cpp b/src/dawn/native/Buffer.cpp
index 22fcffb05f..b2efa6208d 100644
--- a/src/dawn/native/Buffer.cpp
+++ b/src/dawn/native/Buffer.cpp
@@ -101,6 +101,9 @@ class ErrorBuffer final : public BufferBase {
     std::unique_ptr<uint8_t[]> mFakeMappedData;
 };
 
+// GetMappedRange on a zero-sized buffer returns a pointer to this value.
+static uint32_t sZeroSizedMappingData = 0xCAFED00D;
+
 }  // anonymous namespace
 
 MaybeError ValidateBufferDescriptor(DeviceBase* device, const BufferDescriptor* descriptor) {
@@ -435,8 +438,7 @@ void* BufferBase::GetMappedRange(size_t offset, size_t size, bool writable) {
         return static_cast<uint8_t*>(mStagingBuffer->GetMappedPointer()) + offset;
     }
     if (mSize == 0) {
-        static uint32_t zeroRange = 0xCAFED00D;
-        return &zeroRange;
+        return &sZeroSizedMappingData;
     }
     uint8_t* start = static_cast<uint8_t*>(GetMappedPointer());
     return start == nullptr ? nullptr : start + offset;