[llvm] 91edbe2 - [lldb][LoongArch] Fix expression function call failure

[via llvm-commits]

Author: wanglei
Date: 2025-04-23T16:15:29+08:00
New Revision: 91edbe223177504cf878340f37a36dfcee349cab

URL: https://github.com/llvm/llvm-project/commit/91edbe223177504cf878340f37a36dfcee349cab
DIFF: https://github.com/llvm/llvm-project/commit/91edbe223177504cf878340f37a36dfcee349cab.diff

LOG: [lldb][LoongArch] Fix expression function call failure

After upgrading the default code model from small to medium on
LoongArch, function calls using expression may fail. This is because the
function call instruction has changed from `bl` to `pcalau18i + jirl`,
but `RuntimeDyld` does not handle out-of-range jumps for this
instruction sequence.

This patch fixes: #136561

Reviewed By: SixWeining

Pull Request: https://github.com/llvm/llvm-project/pull/136563

Added: 
    

Modified: 
    llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
index f032d5cb30f23..cca99591c8c45 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
@@ -662,7 +662,18 @@ bool RuntimeDyldELF::resolveLoongArch64ShortBranch(
   }
   uint64_t Offset = RelI->getOffset();
   uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset);
-  if (!isInt<28>(Address + Value.Addend - SourceAddress))
+  uint64_t Delta = Address + Value.Addend - SourceAddress;
+  // Normal call
+  if (RelI->getType() == ELF::R_LARCH_B26) {
+    if (!isInt<28>(Delta))
+      return false;
+    resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(),
+                      Value.Addend);
+    return true;
+  }
+  // Medium call: R_LARCH_CALL36
+  // Range: [-128G - 0x20000, +128G - 0x20000)
+  if (((int64_t)Delta + 0x20000) != llvm::SignExtend64(Delta + 0x20000, 38))
     return false;
   resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(),
                     Value.Addend);
@@ -1743,7 +1754,8 @@ RuntimeDyldELF::processRelocationRef(
       processSimpleRelocation(SectionID, Offset, RelType, Value);
     }
   } else if (Arch == Triple::loongarch64) {
-    if (RelType == ELF::R_LARCH_B26 && MemMgr.allowStubAllocation()) {
+    if ((RelType == ELF::R_LARCH_B26 || RelType == ELF::R_LARCH_CALL36) &&
+        MemMgr.allowStubAllocation()) {
       resolveLoongArch64Branch(SectionID, Value, RelI, Stubs);
     } else if (RelType == ELF::R_LARCH_GOT_PC_HI20 ||
                RelType == ELF::R_LARCH_GOT_PC_LO12) {