[compiler-rt] [asan] Re-exec without ASLR if needed on 32-bit Linux (PR #131975)

[Thurston Dang via llvm-commits]

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@@ -109,6 +109,13 @@ void InitializeShadowMemory() {
     ProtectGap(kShadowGap2Beg, kShadowGap2End - kShadowGap2Beg + 1);
     ProtectGap(kShadowGap3Beg, kShadowGap3End - kShadowGap3Beg + 1);
   } else {
+    // The shadow mappings can shadow the entire user address space. However,
+    // on 32-bit systems, the maximum ASLR entropy (currently up to 16-bits
+    // == 256MB) is a significant chunk of the address space; reclaiming it by
+    // disabling ASLR might allow chonky binaries to run.
+    if (sizeof(uptr) == 32)
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thurstond wrote:

> From what I can see, uptr is an alias of uintptr_t, meaning sizeof is 4 on 32bit systems and this branch is never taken on any platform.

You're right, that was a bug. Nice catch :-)

https://github.com/llvm/llvm-project/pull/131975