Move ownership of GCStrategy objects to LLVMContext

Note: This change ended up being slightly more controversial than expected.  Chandler has tentatively okayed this for the moment, but I may be revisiting this in the near future after we settle some high level questions.

Rather than have the GCStrategy object owned by the GCModuleInfo - which is an immutable analysis pass used mainly by gc.root - have it be owned by the LLVMContext. This simplifies the ownership logic (i.e. can you have two instances of the same strategy at once?), but more importantly, allows us to access the GCStrategy in the middle end optimizer. To this end, I add an accessor through Function which becomes the canonical way to get at a GCStrategy instance.

In the near future, this will allows me to move some of the checks from http://reviews.llvm.org/D6808 into the Verifier itself, and to introduce optimization legality predicates for some of the recent additions to InstCombine. (These will follow as separate changes.)

Differential Revision: http://reviews.llvm.org/D6811

llvm-svn: 226311

16 files changed, 64 insertions, 35 deletions

diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index f0b2dfe365b..7f7f5225180 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -23,7 +23,6 @@ add_llvm_library(LLVMCodeGen
   GCMetadata.cpp
   GCMetadataPrinter.cpp
   GCRootLowering.cpp
-  GCStrategy.cpp
   GlobalMerge.cpp
   IfConversion.cpp
   InlineSpiller.cpp
diff --git a/llvm/lib/CodeGen/ErlangGC.cpp b/llvm/lib/CodeGen/ErlangGC.cpp
index 5f2b3a09832..ec2c2e8daf2 100644
--- a/llvm/lib/CodeGen/ErlangGC.cpp
+++ b/llvm/lib/CodeGen/ErlangGC.cpp
@@ -15,8 +15,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/GCs.h"
-#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Target/TargetInstrInfo.h"
diff --git a/llvm/lib/CodeGen/GCMetadata.cpp b/llvm/lib/CodeGen/GCMetadata.cpp
index 6101c679a5d..6f4fa11d6d9 100644
--- a/llvm/lib/CodeGen/GCMetadata.cpp
+++ b/llvm/lib/CodeGen/GCMetadata.cpp
@@ -12,10 +12,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/GCMetadata.h"
-#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/Debug.h"
@@ -61,27 +61,6 @@ GCModuleInfo::GCModuleInfo()
   initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
 }
 
-GCStrategy *GCModuleInfo::getOrCreateStrategy(const Module *M,
-                                              const std::string &Name) {
-  strategy_map_type::iterator NMI = StrategyMap.find(Name);
-  if (NMI != StrategyMap.end())
-    return NMI->getValue();
-  
-  for (GCRegistry::iterator I = GCRegistry::begin(),
-                            E = GCRegistry::end(); I != E; ++I) {
-    if (Name == I->getName()) {
-      std::unique_ptr<GCStrategy> S = I->instantiate();
-      S->Name = Name;
-      StrategyMap[Name] = S.get();
-      StrategyList.push_back(std::move(S));
-      return StrategyList.back().get();
-    }
-  }
- 
-  dbgs() << "unsupported GC: " << Name << "\n";
-  llvm_unreachable(nullptr);
-}
-
 GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
   assert(!F.isDeclaration() && "Can only get GCFunctionInfo for a definition!");
   assert(F.hasGC());
@@ -90,7 +69,15 @@ GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
   if (I != FInfoMap.end())
     return *I->second;
   
-  GCStrategy *S = getOrCreateStrategy(F.getParent(), F.getGC());
+  GCStrategy *S = F.getGCStrategy();
+  if (!S) {
+    std::string error = std::string("unsupported GC: ") + F.getGC();
+    report_fatal_error(error);
+  }
+  // Save the fact this strategy is associated with this module.  Note that
+  // these are non-owning references, the GCStrategy remains owned by the
+  // Context. 
+  StrategyList.push_back(S);
   Functions.push_back(make_unique<GCFunctionInfo>(F, *S));
   GCFunctionInfo *GFI = Functions.back().get();
   FInfoMap[&F] = GFI;
@@ -100,7 +87,6 @@ GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
 void GCModuleInfo::clear() {
   Functions.clear();
   FInfoMap.clear();
-  StrategyMap.clear();
   StrategyList.clear();
 }
 
diff --git a/llvm/lib/CodeGen/GCRootLowering.cpp b/llvm/lib/CodeGen/GCRootLowering.cpp
index 9bda7b8493f..8ff08ece76e 100644
--- a/llvm/lib/CodeGen/GCRootLowering.cpp
+++ b/llvm/lib/CodeGen/GCRootLowering.cpp
@@ -11,13 +11,14 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/CodeGen/GCStrategy.h"
+#include "llvm/CodeGen/GCMetadata.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/IR/Dominators.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/Debug.h"
diff --git a/llvm/lib/CodeGen/OcamlGC.cpp b/llvm/lib/CodeGen/OcamlGC.cpp
index 48db200c513..c5c78529ece 100644
--- a/llvm/lib/CodeGen/OcamlGC.cpp
+++ b/llvm/lib/CodeGen/OcamlGC.cpp
@@ -15,7 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/GCs.h"
-#include "llvm/CodeGen/GCStrategy.h"
+#include "llvm/IR/GCStrategy.h"
 
 using namespace llvm;
 
diff --git a/llvm/lib/CodeGen/Passes.cpp b/llvm/lib/CodeGen/Passes.cpp
index 28e9f847a9d..88cee03fa16 100644
--- a/llvm/lib/CodeGen/Passes.cpp
+++ b/llvm/lib/CodeGen/Passes.cpp
@@ -14,7 +14,6 @@
 
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/Analysis/Passes.h"
-#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/RegAllocRegistry.h"
 #include "llvm/IR/IRPrintingPasses.h"
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 6b3ad5f69b0..a8db35c3a98 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -26,7 +26,6 @@
 #include "llvm/CodeGen/FastISel.h"
 #include "llvm/CodeGen/FunctionLoweringInfo.h"
 #include "llvm/CodeGen/GCMetadata.h"
-#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
@@ -41,6 +40,7 @@
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Instructions.h"
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 7ee06fc153b..6a0a07970a8 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -24,7 +24,6 @@
 #include "llvm/CodeGen/FastISel.h"
 #include "llvm/CodeGen/FunctionLoweringInfo.h"
 #include "llvm/CodeGen/GCMetadata.h"
-#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
@@ -36,6 +35,7 @@
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
diff --git a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
index 33c20d3f219..94f09bdc2f9 100644
--- a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
@@ -16,11 +16,12 @@
 #include "SelectionDAGBuilder.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/GCMetadata.h"
 #include "llvm/CodeGen/FunctionLoweringInfo.h"
-#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/StackMaps.h"
 #include "llvm/IR/CallingConv.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
diff --git a/llvm/lib/CodeGen/ShadowStackGC.cpp b/llvm/lib/CodeGen/ShadowStackGC.cpp
index 0be00f0e7ce..181cb8c435c 100644
--- a/llvm/lib/CodeGen/ShadowStackGC.cpp
+++ b/llvm/lib/CodeGen/ShadowStackGC.cpp
@@ -27,8 +27,8 @@
 
 #include "llvm/CodeGen/GCs.h"
 #include "llvm/ADT/StringExtras.h"
-#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/IR/CallSite.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
diff --git a/llvm/lib/CodeGen/StatepointExampleGC.cpp b/llvm/lib/CodeGen/StatepointExampleGC.cpp
index 09b74ca1d2d..e20b270f42d 100644
--- a/llvm/lib/CodeGen/StatepointExampleGC.cpp
+++ b/llvm/lib/CodeGen/StatepointExampleGC.cpp
@@ -16,7 +16,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/CodeGen/GCStrategy.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Value.h"
 
diff --git a/llvm/lib/IR/CMakeLists.txt b/llvm/lib/IR/CMakeLists.txt
index 1a210e05827..621c7ca9224 100644
--- a/llvm/lib/IR/CMakeLists.txt
+++ b/llvm/lib/IR/CMakeLists.txt
@@ -17,6 +17,7 @@ add_llvm_library(LLVMCore
   Dominators.cpp
   Function.cpp
   GCOV.cpp
+  GCStrategy.cpp
   GVMaterializer.cpp
   Globals.cpp
   IRBuilder.cpp
diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 070513edef2..ddfbaf7a187 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -386,6 +386,12 @@ void Function::clearGC() {
   }
 }
 
+GCStrategy *Function::getGCStrategy() const {
+  // Lookup the GCStrategy (which is owned by the Context), given the name of
+  // the GC in question.
+  return getContext().pImpl->getGCStrategy(getGC());
+}
+
 /// copyAttributesFrom - copy all additional attributes (those not needed to
 /// create a Function) from the Function Src to this one.
 void Function::copyAttributesFrom(const GlobalValue *Src) {
diff --git a/llvm/lib/CodeGen/GCStrategy.cpp b/llvm/lib/IR/GCStrategy.cpp
index 2b687d9dd20..18723a0f514 100644
--- a/llvm/lib/CodeGen/GCStrategy.cpp
+++ b/llvm/lib/IR/GCStrategy.cpp
@@ -12,7 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/CodeGen/GCStrategy.h"
+#include "llvm/IR/GCStrategy.h"
 
 using namespace llvm;
 
diff --git a/llvm/lib/IR/LLVMContextImpl.cpp b/llvm/lib/IR/LLVMContextImpl.cpp
index 01a0e6c98a6..01a786dbfda 100644
--- a/llvm/lib/IR/LLVMContextImpl.cpp
+++ b/llvm/lib/IR/LLVMContextImpl.cpp
@@ -15,6 +15,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/GCStrategy.h"
 #include "llvm/IR/Module.h"
 #include <algorithm>
 using namespace llvm;
@@ -182,3 +183,26 @@ void InsertValueConstantExpr::anchor() { }
 void GetElementPtrConstantExpr::anchor() { }
 
 void CompareConstantExpr::anchor() { }
+
+GCStrategy *LLVMContextImpl::getGCStrategy(const StringRef Name) {
+  // TODO: Arguably, just doing a linear search would be faster for small N
+  auto NMI = GCStrategyMap.find(Name);
+  if (NMI != GCStrategyMap.end())
+    return NMI->getValue();
+  
+  for (auto& Entry : GCRegistry::entries()) {
+    if (Name == Entry.getName()) {
+      std::unique_ptr<GCStrategy> S = Entry.instantiate();
+      S->Name = Name;
+      GCStrategyMap[Name] = S.get();
+      GCStrategyList.push_back(std::move(S));
+      return GCStrategyList.back().get();
+    }
+  }
+
+  // No GCStrategy found for that name, error reporting is the job of our
+  // callers. 
+  return nullptr;
+}
+
+
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 6ebc567f808..45f86093f52 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -41,6 +41,7 @@ class ConstantFP;
 class DiagnosticInfoOptimizationRemark;
 class DiagnosticInfoOptimizationRemarkMissed;
 class DiagnosticInfoOptimizationRemarkAnalysis;
+class GCStrategy;
 class LLVMContext;
 class Type;
 class Value;
@@ -389,6 +390,17 @@ public:
 
   int getOrAddScopeRecordIdxEntry(MDNode *N, int ExistingIdx);
   int getOrAddScopeInlinedAtIdxEntry(MDNode *Scope, MDNode *IA,int ExistingIdx);
+
+  /// An owning list of all GCStrategies which have been created
+  SmallVector<std::unique_ptr<GCStrategy>, 1> GCStrategyList;
+  /// A helper map to speedup lookups into the above list
+  StringMap<GCStrategy*> GCStrategyMap;
+
+  /// Lookup the GCStrategy object associated with the given gc name.  If one
+  /// can't be found, returns nullptr.  The lifetime of the returned objects
+  /// is dictated by the lifetime of the associated context.  No caller should
+  /// attempt to delete the returned objects.
+  GCStrategy *getGCStrategy(const StringRef Name);
   
   LLVMContextImpl(LLVMContext &C);
   ~LLVMContextImpl();