[llvm] [BOLT] Refactor MCInst target symbol lookup. NFCI (PR #129131)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-bolt

Author: Maksim Panchenko (maksfb)

<details>
<summary>Changes</summary>

In analyzeInstructionForFuncReference(), use MCPlusBuilder interface while scanning symbolic operands of MCInst. Should be NFC on x86, but will make the function work on other architectures. Note that it's currently unused on non-x86 as its functionality is exclusive to safe ICF that runs on x86 only.

---
Full diff: https://github.com/llvm/llvm-project/pull/129131.diff


1 Files Affected:

- (modified) bolt/lib/Core/BinaryFunction.cpp (+4-8) 


``````````diff
diff --git a/bolt/lib/Core/BinaryFunction.cpp b/bolt/lib/Core/BinaryFunction.cpp
index ff5eb5cf6e1eb..5a1ff58b72f75 100644
--- a/bolt/lib/Core/BinaryFunction.cpp
+++ b/bolt/lib/Core/BinaryFunction.cpp
@@ -1544,15 +1544,11 @@ MCSymbol *BinaryFunction::registerBranch(uint64_t Src, uint64_t Dst) {
 }
 
 void BinaryFunction::analyzeInstructionForFuncReference(const MCInst &Inst) {
-  for (const MCOperand &Op : MCPlus::primeOperands(Inst)) {
-    if (!Op.isExpr())
+  for (unsigned OpNum = 0; OpNum < MCPlus::getNumPrimeOperands(Inst); ++OpNum) {
+    const MCSymbol *Symbol = BC.MIB->getTargetSymbol(Inst, OpNum);
+    if (!Symbol)
       continue;
-    const MCExpr &Expr = *Op.getExpr();
-    if (Expr.getKind() != MCExpr::SymbolRef)
-      continue;
-    const MCSymbol &Symbol = cast<MCSymbolRefExpr>(Expr).getSymbol();
-    // Set HasAddressTaken for a function regardless of the ICF level.
-    if (BinaryFunction *BF = BC.getFunctionForSymbol(&Symbol))
+    if (BinaryFunction *BF = BC.getFunctionForSymbol(Symbol))
       BF->setHasAddressTaken(true);
   }
 }

``````````

</details>


https://github.com/llvm/llvm-project/pull/129131