[clang] [compiler-rt] [llvm] [RFC] [msan] make MSan up to 20x faster on AMD CPUs (PR #171993)

[Azat Khuzhin via llvm-commits]

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@@ -443,8 +443,8 @@ static const MemoryMapParams Linux_I386_MemoryMapParams = {
 static const MemoryMapParams Linux_X86_64_MemoryMapParams = {
     0,              // AndMask (not used)
     0x500000000000, // XorMask
-    0,              // ShadowBase (not used)
-    0x100000000000, // OriginBase
+    0x200000,       // ShadowBase (== kShadowOffset)
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azat wrote:

I was also worrying about the overhead for other CPUs (since I've tested only few), so making it a compile time switch make sense.

Though it would be nice to have a test for this, but since it is compile time switch it will require separate job (and separate tests, at least one test maybe), what do you think about this?


https://github.com/llvm/llvm-project/pull/171993