[lld] 73b659f - [lld-macho] Fix left shift of negative value UB

[Daniel Bertalan via llvm-commits]

Author: Daniel Bertalan
Date: 2022-07-01T12:00:16+02:00
New Revision: 73b659ff55ea50c7901012ca0b0bde23a83b208b

URL: https://github.com/llvm/llvm-project/commit/73b659ff55ea50c7901012ca0b0bde23a83b208b
DIFF: https://github.com/llvm/llvm-project/commit/73b659ff55ea50c7901012ca0b0bde23a83b208b.diff

LOG: [lld-macho] Fix left shift of negative value UB

I introduced this mistake in 573c7e6b3c79c7ce80a2221e000fab7dd20c0bb4.

Fixes the failure on this UBSan bot:
https://lab.llvm.org/buildbot/#/builders/5/builds/25537

Added: 
    

Modified: 
    lld/MachO/Arch/ARM64.cpp

Removed: 
    


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diff  --git a/lld/MachO/Arch/ARM64.cpp b/lld/MachO/Arch/ARM64.cpp
index 93941f425bf3..7064df5793aa 100644
--- a/lld/MachO/Arch/ARM64.cpp
+++ b/lld/MachO/Arch/ARM64.cpp
@@ -264,7 +264,7 @@ static void writeAdr(void *loc, uint32_t dest, int32_t delta) {
 static void writeNop(void *loc) { write32le(loc, 0xd503201f); }
 
 static void writeLiteralLdr(void *loc, Ldr original, int32_t delta) {
-  uint32_t imm19 = (delta << 3) & 0x00ffffe0;
+  uint32_t imm19 = (delta & 0x001ffffc) << 3;
   uint32_t opcode = 0;
   switch (original.size) {
   case 4: