[PATCH] D92966: scudo: Shrink secondary header and cache entry size by a word on Linux. NFCI.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc created this revision.
pcc added reviewers: hctim, cryptoad, eugenis.
pcc requested review of this revision.
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Normally compilers will allocate space for struct fields even if the
field is an empty struct. Use the [[no_unique_address]] attribute to
suppress that behavior. This attribute that was introduced in C++20,
but compilers that do not support [[no_unique_address]] will ignore
it since it uses C++11 attribute syntax.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D92966

Files:
  compiler-rt/lib/scudo/standalone/secondary.h


Index: compiler-rt/lib/scudo/standalone/secondary.h
===================================================================
--- compiler-rt/lib/scudo/standalone/secondary.h
+++ compiler-rt/lib/scudo/standalone/secondary.h
@@ -31,7 +31,7 @@
   uptr BlockEnd;
   uptr MapBase;
   uptr MapSize;
-  MapPlatformData Data;
+  [[no_unique_address]] MapPlatformData Data;
 };
 
 constexpr uptr getHeaderSize() {
@@ -232,7 +232,7 @@
     uptr BlockEnd;
     uptr MapBase;
     uptr MapSize;
-    MapPlatformData Data;
+    [[no_unique_address]] MapPlatformData Data;
     u64 Time;
   };
 


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