[NFC] Drastically Reduce The Scope of the Global Context

Delete all of the formalism and infrastructure around maintaining our own copy of the global context. The final frontier is the Builtins, which need to lookup intrinsics in a given scratch context and convert them into the appropriate Swift annotations and types. As these utilities have wormed their way through the compiler, I have decided to leave this alone for now.

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

@@ -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

@@ -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/Basic/LLVMContext.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"

lib/Immediate/Immediate.cpp

@@ -20,7 +20,6 @@
 #include "swift/AST/DiagnosticsFrontend.h"
 #include "swift/AST/IRGenRequests.h"
 #include "swift/AST/SILOptions.h"
-#include "swift/Basic/LLVMContext.h"
 #include "swift/Basic/LLVMInitialize.h"
 #include "swift/Frontend/DiagnosticVerifier.h"
 #include "swift/Frontend/Frontend.h"

lib/Immediate/REPL.cpp

@@ -24,7 +24,6 @@
 
 #include "swift/Subsystems.h"
 #include "swift/Basic/LLVMInitialize.h"
-#include "swift/Basic/LLVMContext.h"
 #include "swift/AST/IRGenOptions.h"
 #include "swift/LLVMPasses/PassesFwd.h"
 #include "swift/LLVMPasses/Passes.h"