From 3b47b1f0e23c748ba37a7451724afec648542dfd Mon Sep 17 00:00:00 2001
From: Colin LeMahieu <colinl@codeaurora.org>
Date: Fri, 13 Nov 2015 21:45:50 +0000
Subject: [PATCH] [Hexagon] Fixing memory leak during relaxation by allocating
 MCInst in MCContext.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253090 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../MCTargetDesc/HexagonAsmBackend.cpp        | 27 +++++++++++++++----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp b/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
index b97d616eb49..2f3521bfd71 100644
--- a/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
+++ b/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
@@ -14,9 +14,11 @@
 #include "MCTargetDesc/HexagonMCInstrInfo.h"
 #include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCELFObjectWriter.h"
 #include "llvm/MC/MCFixupKindInfo.h"
 #include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCAsmLayout.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/TargetRegistry.h"
 
@@ -33,14 +35,28 @@ class HexagonAsmBackend : public MCAsmBackend {
   mutable uint64_t relaxedCnt;
   std::unique_ptr <MCInstrInfo> MCII;
   std::unique_ptr <MCInst *> RelaxTarget;
+  MCInst * Extender;
 public:
   HexagonAsmBackend(Target const &T,  uint8_t OSABI, StringRef CPU) :
-    OSABI(OSABI), MCII (T.createMCInstrInfo()), RelaxTarget(new MCInst *){}
+    OSABI(OSABI), MCII (T.createMCInstrInfo()), RelaxTarget(new MCInst *),
+    Extender(nullptr) {}
 
   MCObjectWriter *createObjectWriter(raw_pwrite_stream &OS) const override {
     return createHexagonELFObjectWriter(OS, OSABI, CPU);
   }
 
+  void setExtender(MCContext &Context) const {
+    if (Extender == nullptr)
+      const_cast<HexagonAsmBackend *>(this)->Extender = new (Context) MCInst;
+  }
+
+  MCInst *takeExtender() const {
+    assert(Extender != nullptr);
+    MCInst * Result = Extender;
+    const_cast<HexagonAsmBackend *>(this)->Extender = nullptr;
+    return Result;
+  }
+
   unsigned getNumFixupKinds() const override {
     return Hexagon::NumTargetFixupKinds;
   }
@@ -222,6 +238,7 @@ public:
         if (HexagonMCInstrInfo::bundleSize(MCB) < HEXAGON_PACKET_SIZE) {
           ++relaxedCnt;
           *RelaxTarget = &MCI;
+          setExtender(Layout.getAssembler().getContext());
           return true;
         } else {
           return false;
@@ -262,6 +279,7 @@ public:
       if (HexagonMCInstrInfo::bundleSize(MCB) < HEXAGON_PACKET_SIZE) {
         ++relaxedCnt;
         *RelaxTarget = &MCI;
+        setExtender(Layout.getAssembler().getContext());
         return true;
       }
     }
@@ -293,11 +311,10 @@ public:
         assert((HexagonMCInstrInfo::bundleSize(Res) < HEXAGON_PACKET_SIZE) &&
                "No room to insert extender for relaxation");
 
-        MCInst *HMIx =
-            new MCInst(HexagonMCInstrInfo::deriveExtender(
+        MCInst *HMIx = takeExtender();
+        *HMIx = HexagonMCInstrInfo::deriveExtender(
                 *MCII, CrntHMI,
-                HexagonMCInstrInfo::getExtendableOperand(*MCII, CrntHMI)));
-
+                HexagonMCInstrInfo::getExtendableOperand(*MCII, CrntHMI));
         Res.addOperand(MCOperand::createInst(HMIx));
         *RelaxTarget = nullptr;
       }
-- 
2.34.1