commit 2ad047e04dd4c19defade4799834efacb0024551
author Eli Bendersky <eliben@google.com> Mon Apr 22 21:21:08 2013 +0000
committer Eli Bendersky <eliben@google.com> Mon Apr 22 21:21:08 2013 +0000
tree 02e957d41ae6dede9b3b5de0db47288eed949c77
parent 0af5493701f9982d7451c8b3c1b7699cc84ac94c

Optimize MachineBasicBlock::getSymbol by caching the symbol. Since the symbol
name computation is expensive, this helps save about 25% of the time spent in
this function.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180049 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineBasicBlock.cpp

diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index 898e165..78e9950 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -37,7 +37,7 @@
 
 MachineBasicBlock::MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb)
   : BB(bb), Number(-1), xParent(&mf), Alignment(0), IsLandingPad(false),
-    AddressTaken(false) {
+    AddressTaken(false), CachedMCSymbol(NULL) {
   Insts.Parent = this;
 }
 
@@ -48,12 +48,16 @@
 /// getSymbol - Return the MCSymbol for this basic block.
 ///
 MCSymbol *MachineBasicBlock::getSymbol() const {
-  const MachineFunction *MF = getParent();
-  MCContext &Ctx = MF->getContext();
-  const char *Prefix = Ctx.getAsmInfo().getPrivateGlobalPrefix();
-  return Ctx.GetOrCreateSymbol(Twine(Prefix) + "BB" +
-                               Twine(MF->getFunctionNumber()) + "_" +
-                               Twine(getNumber()));
+  if (!CachedMCSymbol) {
+    const MachineFunction *MF = getParent();
+    MCContext &Ctx = MF->getContext();
+    const char *Prefix = Ctx.getAsmInfo().getPrivateGlobalPrefix();
+    CachedMCSymbol = Ctx.GetOrCreateSymbol(Twine(Prefix) + "BB" +
+                                           Twine(MF->getFunctionNumber()) +
+                                           "_" + Twine(getNumber()));
+  }
+
+  return CachedMCSymbol;
 }