Add hook to insert late LLVM=>LLVM passes just before isel

llvm-svn: 100640

llvm/include/llvm/Target/TargetMachine.h

@@ -264,10 +264,15 @@ public:
                                           bool DisableVerify = true);
   
   /// Target-Independent Code Generator Pass Configuration Options.
-  
-  /// addInstSelector - This method should add any "last minute" LLVM->LLVM
-  /// passes, then install an instruction selector pass, which converts from
-  /// LLVM code to machine instructions.
+
+  /// addPreISelPasses - This method should add any "last minute" LLVM->LLVM
+  /// passes (which are run just before instruction selector).
+  virtual bool addPreISel(PassManagerBase &, CodeGenOpt::Level) {
+    return true;
+  }
+
+  /// addInstSelector - This method should install an instruction selector pass,
+  /// which converts from LLVM code to machine instructions.
   virtual bool addInstSelector(PassManagerBase &, CodeGenOpt::Level) {
     return true;
   }

llvm/lib/CodeGen/LLVMTargetMachine.cpp

@@ -268,6 +268,8 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
 
   PM.add(createStackProtectorPass(getTargetLowering()));
 
+  addPreISel(PM, OptLevel);
+
   if (PrintISelInput)
     PM.add(createPrintFunctionPass("\n\n"
                                    "*** Final LLVM Code input to ISel ***\n",