[BOLT][RelVTable] Skip special handling on non virtual function pointer relocations

[yozhu]

Besides virtual function pointers vtable could contain other kinds of entries
like those for RTTI data that also require relocations. We need to skip special
handling on relocations for non virtual function pointers in relative vtable.

[llvmbot]

@llvm/pr-subscribers-bolt

Author: YongKang Zhu (yozhu)

Changes

Besides virtual function pointers vtable could contain other kinds of entries
like the those for RTTI data that also require relocations. We need to skip
the special handling on the relocations for non virtual function pointers in
relative vtable.

---

Full diff: https://github.com/llvm/llvm-project/pull/137406.diff

1 Files Affected:

• (modified) bolt/lib/Rewrite/RewriteInstance.cpp (+12-13)

diff --git a/bolt/lib/Rewrite/RewriteInstance.cpp b/bolt/lib/Rewrite/RewriteInstance.cpp
index 69fb736d7bde0..1c24200059035 100644
--- a/bolt/lib/Rewrite/RewriteInstance.cpp
+++ b/bolt/lib/Rewrite/RewriteInstance.cpp
@@ -2697,20 +2697,19 @@ void RewriteInstance::handleRelocation(const SectionRef &RelocatedSection,
                BD->nameStartsWith("_ZTCN"))) { // construction vtable
       BinaryFunction *BF = BC->getBinaryFunctionContainingAddress(
           SymbolAddress, /*CheckPastEnd*/ false, /*UseMaxSize*/ true);
-      if (!BF || BF->getAddress() != SymbolAddress) {
-        BC->errs()
-            << "BOLT-ERROR: the virtual function table entry at offset 0x"
-            << Twine::utohexstr(Rel.getOffset());
-        if (BF)
-          BC->errs() << " points to the middle of a function @ 0x"
-                     << Twine::utohexstr(BF->getAddress()) << "\n";
-        else
-          BC->errs() << " does not point to any function\n";
-        exit(1);
+      if (BF) {
+        if (BF->getAddress() != SymbolAddress) {
+          BC->errs()
+              << "BOLT-ERROR: the virtual function table entry at offset 0x"
+              << Twine::utohexstr(Rel.getOffset())
+              << " points to the middle of a function @ 0x"
+              << Twine::utohexstr(BF->getAddress()) << "\n";
+          exit(1);
+        }
+        BC->addRelocation(Rel.getOffset(), BF->getSymbol(), RType, Addend,
+                          ExtractedValue);
+        return;
       }
-      BC->addRelocation(Rel.getOffset(), BF->getSymbol(), RType, Addend,
-                        ExtractedValue);
-      return;
     }
   }
 

[maksfb]

Thanks!