From f84f451a54a483a51ac70f2d80e6c766ef2eb0f7 Mon Sep 17 00:00:00 2001
From: Amir Ayupov <aaupov@fb.com>
Date: Sat, 17 Apr 2021 21:48:46 -0700
Subject: [PATCH] [BOLT][NFC] Use const reference for MCInstrDesc

Summary:
Addressing comments from the review for "Expand auto types".
Use const reference in MCPlusBuilder for MCInstrDesc where the copy
is not necessary.

(cherry picked from FBD27844344)
---
 bolt/src/Passes/LivenessAnalysis.h               |  2 +-
 bolt/src/Passes/ShrinkWrapping.cpp               |  2 +-
 bolt/src/Target/AArch64/AArch64MCPlusBuilder.cpp |  8 ++++----
 bolt/src/Target/X86/X86MCPlusBuilder.cpp         | 10 +++++-----
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/bolt/src/Passes/LivenessAnalysis.h b/bolt/src/Passes/LivenessAnalysis.h
index 585ca0df87b5..d30626a7b9a2 100644
--- a/bolt/src/Passes/LivenessAnalysis.h
+++ b/bolt/src/Passes/LivenessAnalysis.h
@@ -142,7 +142,7 @@ protected:
           BC.MIB->getDefaultLiveOut(Used);
         }
       }
-      const MCInstrDesc InstInfo = BC.MII->get(Point.getOpcode());
+      const MCInstrDesc &InstInfo = BC.MII->get(Point.getOpcode());
       for (unsigned I = 0, E = Point.getNumOperands(); I != E; ++I) {
         if (!Point.getOperand(I).isReg() || I < InstInfo.getNumDefs())
           continue;
diff --git a/bolt/src/Passes/ShrinkWrapping.cpp b/bolt/src/Passes/ShrinkWrapping.cpp
index 77b6df4885cb..d505e33230eb 100644
--- a/bolt/src/Passes/ShrinkWrapping.cpp
+++ b/bolt/src/Passes/ShrinkWrapping.cpp
@@ -264,7 +264,7 @@ void StackLayoutModifier::checkStackPointerRestore(MCInst &Point) {
     return;
   // Check if the definition of SP comes from FP -- in this case, this
   // value may need to be updated depending on our stack layout changes
-  const MCInstrDesc InstInfo = BC.MII->get(Point.getOpcode());
+  const MCInstrDesc &InstInfo = BC.MII->get(Point.getOpcode());
   unsigned NumDefs = InstInfo.getNumDefs();
   bool UsesFP{false};
   for (unsigned I = NumDefs, E = MCPlus::getNumPrimeOperands(Point);
diff --git a/bolt/src/Target/AArch64/AArch64MCPlusBuilder.cpp b/bolt/src/Target/AArch64/AArch64MCPlusBuilder.cpp
index f36366f2ee96..a114a67733d0 100644
--- a/bolt/src/Target/AArch64/AArch64MCPlusBuilder.cpp
+++ b/bolt/src/Target/AArch64/AArch64MCPlusBuilder.cpp
@@ -179,7 +179,7 @@ public:
   bool isLoadFromStack(const MCInst &Inst) const {
     if (!isLoad(Inst))
       return false;
-    const MCInstrDesc InstInfo = Info->get(Inst.getOpcode());
+    const MCInstrDesc &InstInfo = Info->get(Inst.getOpcode());
     unsigned NumDefs = InstInfo.getNumDefs();
     for (unsigned I = NumDefs, E = InstInfo.getNumOperands(); I < E; ++I) {
       const MCOperand &Operand = Inst.getOperand(I);
@@ -225,7 +225,7 @@ public:
       return true;
 
     // Look for literal addressing mode (see C1-143 ARM DDI 0487B.a)
-    const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+    const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
     for (unsigned I = 0, E = MCII.getNumOperands(); I != E; ++I) {
       if (MCII.OpInfo[I].OperandType == MCOI::OPERAND_PCREL)
         return true;
@@ -261,7 +261,7 @@ public:
       return evaluateADR(Inst, DispImm, DispExpr);
 
     // Literal addressing mode
-    const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+    const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
     for (unsigned I = 0, E = MCII.getNumOperands(); I != E; ++I) {
       if (MCII.OpInfo[I].OperandType != MCOI::OPERAND_PCREL)
         continue;
@@ -306,7 +306,7 @@ public:
              "Unexpected number of operands");
       ++OI;
     } else {
-      const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+      const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
       for (unsigned I = 0, E = MCII.getNumOperands(); I != E; ++I) {
         if (MCII.OpInfo[I].OperandType == MCOI::OPERAND_PCREL) {
           break;
diff --git a/bolt/src/Target/X86/X86MCPlusBuilder.cpp b/bolt/src/Target/X86/X86MCPlusBuilder.cpp
index cc5d54e5fc5a..981f684fabaf 100644
--- a/bolt/src/Target/X86/X86MCPlusBuilder.cpp
+++ b/bolt/src/Target/X86/X86MCPlusBuilder.cpp
@@ -622,7 +622,7 @@ public:
       return true;
 
     int MemOpNo = getMemoryOperandNo(Inst);
-    const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+    const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
 
     if (MemOpNo == -1)
       return false;
@@ -635,7 +635,7 @@ public:
       return true;
 
     int MemOpNo = getMemoryOperandNo(Inst);
-    const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+    const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
 
     if (MemOpNo == -1)
       return false;
@@ -1354,7 +1354,7 @@ public:
 
     InstInfo I;
     int MemOpNo = getMemoryOperandNo(Inst);
-    const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+    const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
     // If it is not dealing with a memory operand, we discard it
     if (MemOpNo == -1 || MCII.isCall())
       return false;
@@ -1545,7 +1545,7 @@ public:
       break;
     }
 
-    const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+    const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
     for (int I = 0, E = MCII.getNumDefs(); I != E; ++I) {
       const MCOperand &Operand = Inst.getOperand(I);
       if (Operand.isReg() && Operand.getReg() == X86::RSP) {
@@ -1667,7 +1667,7 @@ public:
 
   bool escapesVariable(const MCInst &Inst, bool HasFramePointer) const override {
     int MemOpNo = getMemoryOperandNo(Inst);
-    const MCInstrDesc MCII = Info->get(Inst.getOpcode());
+    const MCInstrDesc &MCII = Info->get(Inst.getOpcode());
     const unsigned NumDefs = MCII.getNumDefs();
     static BitVector SPBPAliases(BitVector(getAliases(X86::RSP)) |=
                                  getAliases(X86::RBP));