[compiler-rt] Fixing UB on Windows for trampoline allocations (PR #85639)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Zack Johnson (zacklj89)

<details>
<summary>Changes</summary>

This is _actually_ used on Windows, so removing `UNUSED` as well as fixing the type of the constant to avoid undefined behavior with respect to overflow.

---
Full diff: https://github.com/llvm/llvm-project/pull/85639.diff


1 Files Affected:

- (modified) compiler-rt/lib/interception/interception_win.cpp (+1-1) 


``````````diff
diff --git a/compiler-rt/lib/interception/interception_win.cpp b/compiler-rt/lib/interception/interception_win.cpp
index 1829358705fe82..3602b24401a3a1 100644
--- a/compiler-rt/lib/interception/interception_win.cpp
+++ b/compiler-rt/lib/interception/interception_win.cpp
@@ -339,7 +339,7 @@ struct TrampolineMemoryRegion {
   uptr max_size;
 };
 
-UNUSED static const uptr kTrampolineScanLimitRange = 1 << 31;  // 2 gig
+static const uptr kTrampolineScanLimitRange = 1ull << 31;  // 2 gig
 static const int kMaxTrampolineRegion = 1024;
 static TrampolineMemoryRegion TrampolineRegions[kMaxTrampolineRegion];
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/85639