5 files changed, 69 insertions, 16 deletions

diff --git a/include/llvm/CodeGen/Passes.h b/include/llvm/CodeGen/Passes.h
index e9778f66f6..2e4fb99081 100644
--- a/include/llvm/CodeGen/Passes.h
+++ b/include/llvm/CodeGen/Passes.h
@@ -33,6 +33,8 @@ namespace llvm {
 
 extern char &NoPassID; // Allow targets to choose not to run a pass.
 
+class PassConfigImpl;
+
 /// Target-Independent Code Generator Pass Configuration Options.
 ///
 /// This is an ImmutablePass solely for the purpose of exposing CodeGen options
@@ -41,7 +43,8 @@ class TargetPassConfig : public ImmutablePass {
 protected:
   TargetMachine *TM;
   PassManagerBase ±
-  bool Initialized; // Flagged after all passes are configured.
+  PassConfigImpl *Impl; // Internal data structures
+  bool Initialized;     // Flagged after all passes are configured.
 
   // Target Pass Options
   // Targets provide a default setting, user flags override.
@@ -69,6 +72,7 @@ public:
     return TM->getTargetLowering();
   }
 
+  //
   void setInitialized() { Initialized = true; }
 
   CodeGenOpt::Level getOptLevel() const { return TM->getOptLevel(); }
@@ -78,6 +82,18 @@ public:
   bool getEnableTailMerge() const { return EnableTailMerge; }
   void setEnableTailMerge(bool Enable) { setOpt(EnableTailMerge, Enable); }
 
+  /// Allow the target to override a specific pass without overriding the pass
+  /// pipeline. When passes are added to the standard pipeline at the
+  /// point where StadardID is expected, add TargetID in its place.
+  void substitutePass(char &StandardID, char &TargetID);
+
+  /// Allow the target to disable a specific standard pass.
+  void disablePass(char &ID) { substitutePass(ID, NoPassID); }
+
+  /// Return the pass ssubtituted for StandardID by the target.
+  /// If no substitution exists, return StandardID.
+  AnalysisID getPassSubstitution(AnalysisID StandardID) const;
+
   /// Return true if the optimized regalloc pipeline is enabled.
   bool getOptimizeRegAlloc() const;
 
@@ -187,8 +203,9 @@ protected:
   /// Utilities for targets to add passes to the pass manager.
   ///
 
-  /// Add a target-independent CodeGen pass at this point in the pipeline.
-  void addPass(char &ID);
+  /// Add a CodeGen pass at this point in the pipeline after checking overrides.
+  /// Return the pass that was added, or NoPassID.
+  AnalysisID addPass(char &ID);
 
   /// addMachinePasses helper to create the target-selected or overriden
   /// regalloc pass.
diff --git a/include/llvm/Pass.h b/include/llvm/Pass.h
index a0cbca121d..888537daa4 100644
--- a/include/llvm/Pass.h
+++ b/include/llvm/Pass.h
@@ -177,7 +177,7 @@ public:
 
   // createPass - Create a object for the specified pass class,
   // or null if it is not known.
-  static Pass *createPass(char &TI);
+  static Pass *createPass(AnalysisID ID);
 
   /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
   /// get analysis information that might be around, for example to update it.
diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index 285d5df634..427e4ac327 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -115,16 +115,34 @@ char TargetPassConfig::ID = 0;
 static char NoPassIDAnchor = 0;
 char &llvm::NoPassID = NoPassIDAnchor;
 
+namespace llvm {
+class PassConfigImpl {
+public:
+  // List of passes explicitly substituted by this target. Normally this is
+  // empty, but it is a convenient way to suppress or replace specific passes
+  // that are part of a standard pass pipeline without overridding the entire
+  // pipeline. This mechanism allows target options to inherit a standard pass's
+  // user interface. For example, a target may disable a standard pass by
+  // default by substituting NoPass, and the user may still enable that standard
+  // pass with an explicit command line option.
+  DenseMap<AnalysisID,AnalysisID> TargetPasses;
+};
+} // namespace llvm
+
 // Out of line virtual method.
-TargetPassConfig::~TargetPassConfig() {}
+TargetPassConfig::~TargetPassConfig() {
+  delete Impl;
+}
 
 // Out of line constructor provides default values for pass options and
 // registers all common codegen passes.
 TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm)
-  : ImmutablePass(ID), TM(tm), PM(pm), Initialized(false),
+  : ImmutablePass(ID), TM(tm), PM(pm), Impl(0), Initialized(false),
     DisableVerify(false),
     EnableTailMerge(true) {
 
+  Impl = new PassConfigImpl();
+
   // Register all target independent codegen passes to activate their PassIDs,
   // including this pass itself.
   initializeCodeGen(*PassRegistry::getPassRegistry());
@@ -149,15 +167,33 @@ void TargetPassConfig::setOpt(bool &Opt, bool Val) {
   Opt = Val;
 }
 
-void TargetPassConfig::addPass(char &ID) {
-  if (&ID == &NoPassID)
-    return;
+void TargetPassConfig::substitutePass(char &StandardID, char &TargetID) {
+  Impl->TargetPasses[&StandardID] = &TargetID;
+}
 
+AnalysisID TargetPassConfig::getPassSubstitution(AnalysisID ID) const {
+  DenseMap<AnalysisID, AnalysisID>::const_iterator
+    I = Impl->TargetPasses.find(ID);
+  if (I == Impl->TargetPasses.end())
+    return ID;
+  return I->second;
+}
+
+/// Add a CodeGen pass at this point in the pipeline after checking for target
+/// and command line overrides.
+AnalysisID TargetPassConfig::addPass(char &ID) {
+  assert(!Initialized && "PassConfig is immutable");
+
+  AnalysisID FinalID = getPassSubstitution(&ID);
   // FIXME: check user overrides
-  Pass *P = Pass::createPass(ID);
+  if (FinalID == &NoPassID)
+    return FinalID;
+
+  Pass *P = Pass::createPass(FinalID);
   if (!P)
     llvm_unreachable("Pass ID not registered");
   PM.add(P);
+  return FinalID;
 }
 
 void TargetPassConfig::printNoVerify(const char *Banner) const {
diff --git a/lib/Target/PTX/PTXTargetMachine.cpp b/lib/Target/PTX/PTXTargetMachine.cpp
index 056bc07efa..61285b1545 100644
--- a/lib/Target/PTX/PTXTargetMachine.cpp
+++ b/lib/Target/PTX/PTXTargetMachine.cpp
@@ -151,11 +151,11 @@ bool PTXPassConfig::addPostRegAlloc() {
 
 /// Add passes that optimize machine instructions after register allocation.
 void PTXPassConfig::addMachineLateOptimization() {
-  addPass(BranchFolderPassID);
-  printNoVerify("After BranchFolding");
+  if (addPass(BranchFolderPassID) != &NoPassID)
+    printNoVerify("After BranchFolding");
 
-  addPass(TailDuplicateID);
-  printNoVerify("After TailDuplicate");
+  if (addPass(TailDuplicateID) != &NoPassID)
+    printNoVerify("After TailDuplicate");
 }
 
 bool PTXPassConfig::addPreEmitPass() {
diff --git a/lib/VMCore/Pass.cpp b/lib/VMCore/Pass.cpp
index 07ac3c35c1..994a7ffcee 100644
--- a/lib/VMCore/Pass.cpp
+++ b/lib/VMCore/Pass.cpp
@@ -189,8 +189,8 @@ const PassInfo *Pass::lookupPassInfo(StringRef Arg) {
   return PassRegistry::getPassRegistry()->getPassInfo(Arg);
 }
 
-Pass *Pass::createPass(char &TI) {
-  const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(&TI);
+Pass *Pass::createPass(AnalysisID ID) {
+  const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(ID);
   if (!PI)
     return NULL;
   return PI->createPass();