Merge pull request swiftlang#31106 from CodaFi/globe-star

[NFC] Drastically Reduce The Scope of the "Global LLVMContext"

Author: CodaFi

include/swift/Basic/LLVMContext.h

@@ -233,9 +233,6 @@ class SILModule {
   // The list of SILProperties in the module.
   PropertyListType properties;
 
-  /// The remark output stream used to record SIL remarks to a file.
-  std::unique_ptr<llvm::raw_fd_ostream> silRemarkStream;
-
   /// The remark streamer used to serialize SIL remarks to a file.
   std::unique_ptr<swift::SILRemarkStreamer> silRemarkStreamer;
 
@@ -526,9 +523,7 @@ class SILModule {
   swift::SILRemarkStreamer *getSILRemarkStreamer() {
     return silRemarkStreamer.get();
   }
-  void setSILRemarkStreamer(
-      std::unique_ptr<llvm::raw_fd_ostream> &&remarkStream,
-      std::unique_ptr<swift::SILRemarkStreamer> &&remarkStreamer);
+  void installSILRemarkStreamer();
 
   // This is currently limited to VarDecl because the visibility of global
   // variables and class properties is straightforward, while the visibility of

include/swift/SIL/SILModule.h

@@ -25,31 +25,39 @@
 namespace swift {
 
 class SILRemarkStreamer {
-  llvm::remarks::RemarkStreamer &llvmStreamer;
+private:
+  /// The \c LLVMContext the underlying streamer uses for scratch space.
+  std::unique_ptr<llvm::LLVMContext> streamerContext;
+  /// The remark output stream used to record SIL remarks to a file.
+  std::unique_ptr<llvm::raw_fd_ostream> remarkStream;
+
   // Source manager for resolving source locations.
-  const SourceManager &srcMgr;
+  const ASTContext &ctx;
   /// Convert diagnostics into LLVM remark objects.
   /// The lifetime of the members of the result is bound to the lifetime of
   /// the SIL remarks.
   template <typename RemarkT>
   llvm::remarks::Remark
   toLLVMRemark(const OptRemark::Remark<RemarkT> &remark) const;
 
+  SILRemarkStreamer(std::unique_ptr<llvm::remarks::RemarkStreamer> &&streamer,
+                    std::unique_ptr<llvm::raw_fd_ostream> &&stream,
+                    const ASTContext &Ctx);
+
+public:
+  static std::unique_ptr<SILRemarkStreamer> create(SILModule &silModule);
+
 public:
-  SILRemarkStreamer(llvm::remarks::RemarkStreamer &llvmStreamer,
-                    const SourceManager &srcMgr)
-      : llvmStreamer(llvmStreamer), srcMgr(srcMgr) {}
+  llvm::remarks::RemarkStreamer &getLLVMStreamer();
+  const llvm::remarks::RemarkStreamer &getLLVMStreamer() const;
+
+  const ASTContext &getASTContext() const { return ctx; }
+
   /// Emit a remark through the streamer.
   template <typename RemarkT>
   void emit(const OptRemark::Remark<RemarkT> &remark);
 };
 
-std::pair<std::unique_ptr<llvm::raw_fd_ostream>,
-          std::unique_ptr<SILRemarkStreamer>>
-createSILRemarkStreamer(SILModule &srcMgr, StringRef filename, StringRef passes,
-                        llvm::remarks::Format format,
-                        DiagnosticEngine &diagEngine, SourceManager &sourceMgr);
-
 // Implementation for template member functions.
 
 // OptRemark type -> llvm::remarks::Type
@@ -80,24 +88,26 @@ llvm::remarks::Remark SILRemarkStreamer::toLLVMRemark(
   llvmRemark.PassName = optRemark.getPassName();
   llvmRemark.RemarkName = optRemark.getIdentifier();
   llvmRemark.FunctionName = optRemark.getDemangledFunctionName();
-  llvmRemark.Loc = toRemarkLocation(optRemark.getLocation(), srcMgr);
+  llvmRemark.Loc =
+      toRemarkLocation(optRemark.getLocation(), getASTContext().SourceMgr);
 
   for (const OptRemark::Argument &arg : optRemark.getArgs()) {
     llvmRemark.Args.emplace_back();
     llvmRemark.Args.back().Key = arg.key;
     llvmRemark.Args.back().Val = arg.val;
-    llvmRemark.Args.back().Loc = toRemarkLocation(arg.loc, srcMgr);
+    llvmRemark.Args.back().Loc =
+        toRemarkLocation(arg.loc, getASTContext().SourceMgr);
   }
 
   return llvmRemark;
 }
 
 template <typename RemarkT>
 void SILRemarkStreamer::emit(const OptRemark::Remark<RemarkT> &optRemark) {
-  if (!llvmStreamer.matchesFilter(optRemark.getPassName()))
+  if (!getLLVMStreamer().matchesFilter(optRemark.getPassName()))
     return;
 
-  return llvmStreamer.getSerializer().emit(toLLVMRemark(optRemark));
+  return getLLVMStreamer().getSerializer().emit(toLLVMRemark(optRemark));
 }
 
 } // namespace swift

include/swift/SIL/SILRemarkStreamer.h

@@ -20,17 +20,30 @@
 #include "swift/AST/Module.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/TypeCheckRequests.h"
-#include "swift/Basic/LLVMContext.h"
 #include "swift/Strings.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
+#include "llvm/Support/ManagedStatic.h"
 #include <tuple>
+
 using namespace swift;
 
+// FIXME: The "Global Context" is a holdover from LLVM's removal of the global
+// context. LLVM's global context was used as scratch space to allocate some
+// attributes for the routines in this file, so we just made our own to work
+// around its removal. Really, it doesn't matter where we allocate these
+// attributes, but it's somewhat convenient for now that they're all in one
+// place instead of requiring a fresh context for every call. If we can
+// sequester ownership of a context (e.g. in SILModule) we could do away with
+// this, but there are callers of \c swift::getSwiftFunctionTypeForIntrinsic
+// all over the compiler.
+static llvm::ManagedStatic<llvm::LLVMContext> GlobalContext;
+static llvm::LLVMContext &getGlobalLLVMContext() { return *GlobalContext; }
+
 struct BuiltinExtraInfoTy {
   const char *Attributes;
 };

lib/AST/Builtins.cpp

@@ -49,7 +49,6 @@ add_swift_host_library(swiftBasic STATIC
   FileTypes.cpp
   JSONSerialization.cpp
   LangOptions.cpp
-  LLVMContext.cpp
   Located.cpp
   Mangler.cpp
   OutputFileMap.cpp

lib/Basic/CMakeLists.txt

@@ -41,7 +41,6 @@
 #include "swift/Basic/Edit.h"
 #include "swift/Basic/FileSystem.h"
 #include "swift/Basic/JSONSerialization.h"
-#include "swift/Basic/LLVMContext.h"
 #include "swift/Basic/LLVMInitialize.h"
 #include "swift/Basic/Platform.h"
 #include "swift/Basic/PrettyStackTrace.h"
@@ -779,8 +778,6 @@ static bool buildModuleFromInterface(const CompilerInvocation &Invocation,
 
 static bool compileLLVMIR(const CompilerInvocation &Invocation,
                           CompilerInstance &Instance) {
-  auto &LLVMContext = getGlobalLLVMContext();
-
   // Load in bitcode file.
   assert(Invocation.getFrontendOptions().InputsAndOutputs.hasSingleInput() &&
          "We expect a single input for bitcode input!");
@@ -800,8 +797,9 @@ static bool compileLLVMIR(const CompilerInvocation &Invocation,
   llvm::MemoryBuffer *MainFile = FileBufOrErr.get().get();
 
   llvm::SMDiagnostic Err;
+  auto LLVMContext = std::make_unique<llvm::LLVMContext>();
   std::unique_ptr<llvm::Module> Module =
-      llvm::parseIR(MainFile->getMemBufferRef(), Err, LLVMContext);
+      llvm::parseIR(MainFile->getMemBufferRef(), Err, *LLVMContext.get());
   if (!Module) {
     // TODO: Translate from the diagnostic info to the SourceManager location
     // if available.
@@ -1558,7 +1556,6 @@ static bool performCompileStepsPostSILGen(
   FrontendOptions opts = Invocation.getFrontendOptions();
   FrontendOptions::ActionType Action = opts.RequestedAction;
   const ASTContext &Context = Instance.getASTContext();
-  const SILOptions &SILOpts = Invocation.getSILOptions();
   const IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
 
   Optional<BufferIndirectlyCausingDiagnosticRAII> ricd;
@@ -1582,10 +1579,7 @@ static bool performCompileStepsPostSILGen(
     return Context.hadError();
   }
 
-  auto pair = createSILRemarkStreamer(
-      *SM, SILOpts.OptRecordFile, SILOpts.OptRecordPasses,
-      SILOpts.OptRecordFormat, Instance.getDiags(), Instance.getSourceMgr());
-  SM->setSILRemarkStreamer(std::move(pair.first), std::move(pair.second));
+  SM->installSILRemarkStreamer();
 
   // This is the action to be used to serialize SILModule.
   // It may be invoked multiple times, but it will perform

lib/Basic/LLVMContext.cpp

@@ -25,7 +25,6 @@
 #include "swift/AST/IRGenRequests.h"
 #include "swift/AST/Module.h"
 #include "swift/Basic/LLVM.h"
-#include "swift/Basic/LLVMContext.h"
 #include "swift/Frontend/Frontend.h"
 #include "swift/IRGen/IRGenPublic.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"

lib/FrontendTool/FrontendTool.cpp

@@ -22,7 +22,6 @@
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/NameLookupRequests.h"
-#include "swift/Basic/LLVMContext.h"
 #include "swift/Frontend/Frontend.h"
 #include "swift/IDE/REPLCodeCompletion.h"
 #include "swift/IDE/Utils.h"
@@ -765,13 +764,13 @@ static void printOrDumpDecl(Decl *d, PrintOrDump which) {
 
 /// The compiler and execution environment for the REPL.
 class REPLEnvironment {
+  std::unique_ptr<llvm::LLVMContext> LLVMContext;
   CompilerInstance &CI;
   ModuleDecl *MostRecentModule;
   ProcessCmdLine CmdLine;
   llvm::SmallPtrSet<swift::ModuleDecl *, 8> ImportedModules;
   SmallVector<llvm::Function*, 8> InitFns;
   bool RanGlobalInitializers;
-  llvm::LLVMContext &LLVMContext;
   llvm::Module *Module;
   llvm::StringSet<> FuncsAlreadyGenerated;
   llvm::StringSet<> GlobalsAlreadyEmitted;
@@ -1028,15 +1027,14 @@ class REPLEnvironment {
 public:
   REPLEnvironment(CompilerInstance &CI,
                   const ProcessCmdLine &CmdLine,
-                  llvm::LLVMContext &LLVMCtx,
                   bool ParseStdlib)
-    : CI(CI),
+    : LLVMContext(std::make_unique<llvm::LLVMContext>()),
+      CI(CI),
       MostRecentModule(CI.getMainModule()),
       CmdLine(CmdLine),
       RanGlobalInitializers(false),
-      LLVMContext(LLVMCtx),
-      Module(new llvm::Module("REPL", LLVMContext)),
-      DumpModule("REPL", LLVMContext),
+      Module(new llvm::Module("REPL", *LLVMContext.get())),
+      DumpModule("REPL", *LLVMContext.get()),
       IRGenOpts(),
       SILOpts(),
       Input(*this)
@@ -1281,7 +1279,7 @@ void PrettyStackTraceREPL::print(llvm::raw_ostream &out) const {
 
 void swift::runREPL(CompilerInstance &CI, const ProcessCmdLine &CmdLine,
                     bool ParseStdlib) {
-  REPLEnvironment env(CI, CmdLine, getGlobalLLVMContext(), ParseStdlib);
+  REPLEnvironment env(CI, CmdLine, ParseStdlib);
   if (CI.getASTContext().hadError())
     return;
 

lib/Immediate/Immediate.cpp

@@ -28,6 +28,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/YAMLTraits.h"
 #include <functional>
@@ -698,11 +699,9 @@ void SILModule::serialize() {
   setSerialized();
 }
 
-void SILModule::setSILRemarkStreamer(
-    std::unique_ptr<llvm::raw_fd_ostream> &&remarkStream,
-    std::unique_ptr<swift::SILRemarkStreamer> &&remarkStreamer) {
-  silRemarkStream = std::move(remarkStream);
-  silRemarkStreamer = std::move(remarkStreamer);
+void SILModule::installSILRemarkStreamer() {
+  assert(!silRemarkStreamer && "SIL Remark Streamer is already installed!");
+  silRemarkStreamer = SILRemarkStreamer::create(*this);
 }
 
 bool SILModule::isStdlibModule() const {