libbcc

Change-Id: Ieaa3ebd5a38f370752495549f8870b534eeedfc5
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index 40e0150..5e88865 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -14,6 +14,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/PassManager.h"
 #include "llvm/Pass.h"
+#include "llvm/Analysis/Verifier.h"
 #include "llvm/Assembly/PrintModulePass.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/Passes.h"
@@ -66,6 +67,9 @@
     cl::desc("Verify generated machine code"),
     cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
 
+static cl::opt<bool> EnableMachineCSE("enable-machine-cse", cl::Hidden,
+    cl::desc("Enable Machine CSE"));
+
 static cl::opt<cl::boolOrDefault>
 AsmVerbose("asm-verbose", cl::desc("Add comments to directives."),
            cl::init(cl::BOU_UNSET));
@@ -114,9 +118,10 @@
 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
                                             formatted_raw_ostream &Out,
                                             CodeGenFileType FileType,
-                                            CodeGenOpt::Level OptLevel) {
+                                            CodeGenOpt::Level OptLevel,
+                                            bool DisableVerify) {
   // Add common CodeGen passes.
-  if (addCommonCodeGenPasses(PM, OptLevel))
+  if (addCommonCodeGenPasses(PM, OptLevel, DisableVerify))
     return true;
 
   OwningPtr<MCContext> Context(new MCContext());
@@ -140,7 +145,7 @@
   case CGFT_ObjectFile: {
     // Create the code emitter for the target if it exists.  If not, .o file
     // emission fails.
-    MCCodeEmitter *MCE = getTarget().createCodeEmitter(*this);
+    MCCodeEmitter *MCE = getTarget().createCodeEmitter(*this, *Context);
     if (MCE == 0)
       return true;
     
@@ -192,12 +197,13 @@
 ///
 bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
                                                    JITCodeEmitter &JCE,
-                                                   CodeGenOpt::Level OptLevel) {
+                                                   CodeGenOpt::Level OptLevel,
+                                                   bool DisableVerify) {
   // Make sure the code model is set.
   setCodeModelForJIT();
   
   // Add common CodeGen passes.
-  if (addCommonCodeGenPasses(PM, OptLevel))
+  if (addCommonCodeGenPasses(PM, OptLevel, DisableVerify))
     return true;
 
   addCodeEmitter(PM, OptLevel, JCE);
@@ -206,6 +212,12 @@
   return false; // success!
 }
 
+static void printNoVerify(PassManagerBase &PM,
+                           const char *Banner) {
+  if (PrintMachineCode)
+    PM.add(createMachineFunctionPrinterPass(dbgs(), Banner));
+}
+
 static void printAndVerify(PassManagerBase &PM,
                            const char *Banner,
                            bool allowDoubleDefs = false) {
@@ -220,13 +232,19 @@
 /// emitting to assembly files or machine code output.
 ///
 bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
-                                               CodeGenOpt::Level OptLevel) {
+                                               CodeGenOpt::Level OptLevel,
+                                               bool DisableVerify) {
   // Standard LLVM-Level Passes.
 
+  // Before running any passes, run the verifier to determine if the input
+  // coming from the front-end and/or optimizer is valid.
+  if (!DisableVerify)
+    PM.add(createVerifierPass());
+
   // Optionally, tun split-GEPs and no-load GVN.
   if (EnableSplitGEPGVN) {
     PM.add(createGEPSplitterPass());
-    PM.add(createGVNPass(/*NoPRE=*/false, /*NoLoads=*/true));
+    PM.add(createGVNPass(/*NoLoads=*/true));
   }
 
   // Run loop strength reduction before anything else.
@@ -273,6 +291,11 @@
                                    "*** Final LLVM Code input to ISel ***\n",
                                    &dbgs()));
 
+  // All passes which modify the LLVM IR are now complete; run the verifier
+  // to ensure that the IR is valid.
+  if (!DisableVerify)
+    PM.add(createVerifierPass());
+
   // Standard Lower-Level Passes.
 
   // Set up a MachineFunction for the rest of CodeGen to work on.
@@ -291,6 +314,10 @@
   printAndVerify(PM, "After Instruction Selection",
                  /* allowDoubleDefs= */ true);
 
+  // Optimize PHIs before DCE: removing dead PHI cycles may make more
+  // instructions dead.
+  if (OptLevel != CodeGenOpt::None)
+    PM.add(createOptimizePHIsPass());
 
   // Delete dead machine instructions regardless of optimization level.
   PM.add(createDeadMachineInstructionElimPass());
@@ -301,6 +328,8 @@
     PM.add(createOptimizeExtsPass());
     if (!DisableMachineLICM)
       PM.add(createMachineLICMPass());
+    if (EnableMachineCSE)
+      PM.add(createMachineCSEPass());
     if (!DisableMachineSink)
       PM.add(createMachineSinkingPass());
     printAndVerify(PM, "After MachineLICM and MachineSinking",
@@ -355,13 +384,13 @@
   // Branch folding must be run after regalloc and prolog/epilog insertion.
   if (OptLevel != CodeGenOpt::None && !DisableBranchFold) {
     PM.add(createBranchFoldingPass(getEnableTailMergeDefault()));
-    printAndVerify(PM, "After BranchFolding");
+    printNoVerify(PM, "After BranchFolding");
   }
 
   // Tail duplication.
   if (OptLevel != CodeGenOpt::None && !DisableTailDuplicate) {
     PM.add(createTailDuplicatePass(false));
-    printAndVerify(PM, "After TailDuplicate");
+    printNoVerify(PM, "After TailDuplicate");
   }
 
   PM.add(createGCMachineCodeAnalysisPass());
@@ -371,11 +400,11 @@
 
   if (OptLevel != CodeGenOpt::None && !DisableCodePlace) {
     PM.add(createCodePlacementOptPass());
-    printAndVerify(PM, "After CodePlacementOpt");
+    printNoVerify(PM, "After CodePlacementOpt");
   }
 
   if (addPreEmitPass(PM, OptLevel))
-    printAndVerify(PM, "After PreEmit passes");
+    printNoVerify(PM, "After PreEmit passes");
 
   return false;
 }