[Macros] Create llvm::MemoryBuffer directly from macro expansion result

Saves one memory copy. No need to create a temporary
NullTerminatedStringRef.

Author: rintaro

lib/Sema/TypeCheckMacros.cpp

@@ -677,7 +677,7 @@ Expr *swift::expandMacroExpr(
     return nullptr;
 
   // Evaluate the macro.
-  NullTerminatedStringRef evaluatedSource;
+  std::unique_ptr<llvm::MemoryBuffer> evaluatedSource;
 
   MacroDecl *macro = cast<MacroDecl>(macroRef.getDecl());
 
@@ -722,8 +722,7 @@ Expr *swift::expandMacroExpr(
     // Expand the definition with the given arguments.
     auto result = expandMacroDefinition(
         macroDef.getExpanded(), macro, expr->getArgs());
-    llvm::MallocAllocator allocator;
-    evaluatedSource = NullTerminatedStringRef(result, allocator);
+    evaluatedSource = llvm::MemoryBuffer::getMemBufferCopy(result);
     break;
   }
 
@@ -763,8 +762,9 @@ Expr *swift::expandMacroExpr(
         &evaluatedSourceLength);
     if (!evaluatedSourceAddress)
       return nullptr;
-    evaluatedSource = NullTerminatedStringRef(evaluatedSourceAddress,
-                                              (size_t)evaluatedSourceLength);
+    evaluatedSource = llvm::MemoryBuffer::getMemBufferCopy(
+        {evaluatedSourceAddress, (size_t)evaluatedSourceLength});
+    free((void *)evaluatedSourceAddress);
     break;
 #else
     ctx.Diags.diagnose(expr->getLoc(), diag::macro_unsupported);
@@ -785,14 +785,13 @@ Expr *swift::expandMacroExpr(
   if (ctx.LangOpts.DumpMacroExpansions) {
     llvm::errs() << bufferName << " as " << expandedType.getString()
                  << "\n------------------------------\n"
-                 << evaluatedSource
+                 << evaluatedSource->getBuffer()
                  << "\n------------------------------\n";
   }
 
   // Create a new source buffer with the contents of the expanded macro.
-  auto macroBuffer =
-      llvm::MemoryBuffer::getMemBufferCopy(evaluatedSource, bufferName);
-  unsigned macroBufferID = sourceMgr.addNewSourceBuffer(std::move(macroBuffer));
+  unsigned macroBufferID =
+      sourceMgr.addNewSourceBuffer(std::move(evaluatedSource));
   auto macroBufferRange = sourceMgr.getRangeForBuffer(macroBufferID);
   GeneratedSourceInfo sourceInfo{
     GeneratedSourceInfo::ExpressionMacroExpansion,
@@ -803,7 +802,6 @@ Expr *swift::expandMacroExpr(
     dc
   };
   sourceMgr.setGeneratedSourceInfo(macroBufferID, sourceInfo);
-  free((void*)evaluatedSource.data());
 
   // Create a source file to hold the macro buffer. This is automatically
   // registered with the enclosing module.
@@ -866,7 +864,7 @@ swift::expandFreestandingMacro(MacroExpansionDecl *med) {
     return None;
 
   // Evaluate the macro.
-  NullTerminatedStringRef evaluatedSource;
+  std::unique_ptr<llvm::MemoryBuffer> evaluatedSource;
 
   MacroDecl *macro = cast<MacroDecl>(med->getMacroRef().getDecl());
   auto macroRoles = macro->getMacroRoles();
@@ -899,8 +897,7 @@ swift::expandFreestandingMacro(MacroExpansionDecl *med) {
     // Expand the definition with the given arguments.
     auto result = expandMacroDefinition(
         macroDef.getExpanded(), macro, med->getArgs());
-    llvm::MallocAllocator allocator;
-    evaluatedSource = NullTerminatedStringRef(result, allocator);
+    evaluatedSource = llvm::MemoryBuffer::getMemBufferCopy(result);
     break;
   }
 
@@ -958,8 +955,9 @@ swift::expandFreestandingMacro(MacroExpansionDecl *med) {
         &evaluatedSourceLength);
     if (!evaluatedSourceAddress)
       return None;
-    evaluatedSource = NullTerminatedStringRef(evaluatedSourceAddress,
-                                              (size_t)evaluatedSourceLength);
+    evaluatedSource = llvm::MemoryBuffer::getMemBufferCopy(
+        {evaluatedSourceAddress, (size_t)evaluatedSourceLength});
+    free((void *)evaluatedSourceAddress);
     break;
 #else
     med->diagnose(diag::macro_unsupported);
@@ -987,7 +985,8 @@ swift::expandFreestandingMacro(MacroExpansionDecl *med) {
   // Create a new source buffer with the contents of the expanded macro.
   auto macroBuffer =
       llvm::MemoryBuffer::getMemBufferCopy(evaluatedSource, bufferName);
-  unsigned macroBufferID = sourceMgr.addNewSourceBuffer(std::move(macroBuffer));
+  unsigned macroBufferID =
+      sourceMgr.addNewSourceBuffer(std::move(evaluatedSource));
   auto macroBufferRange = sourceMgr.getRangeForBuffer(macroBufferID);
   GeneratedSourceInfo sourceInfo{
       GeneratedSourceInfo::FreestandingDeclMacroExpansion,
@@ -1092,7 +1091,7 @@ evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo, CustomAttr *attr,
   }
 
   // Evaluate the macro.
-  NullTerminatedStringRef evaluatedSource;
+  std::unique_ptr<llvm::MemoryBuffer> evaluatedSource;
 
   std::string discriminator;
   auto macroDef = macro->getDefinition();
@@ -1115,7 +1114,7 @@ evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo, CustomAttr *attr,
     auto result = expandMacroDefinition(
         macroDef.getExpanded(), macro, attr->getArgs());
     llvm::MallocAllocator allocator;
-    evaluatedSource = NullTerminatedStringRef(result, allocator);
+    evaluatedSource = llvm::MemoryBuffer::getMemBufferCopy(result);
     break;
   }
 
@@ -1179,8 +1178,9 @@ evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo, CustomAttr *attr,
         &evaluatedSourceLength);
     if (!evaluatedSourceAddress)
       return nullptr;
-    evaluatedSource = NullTerminatedStringRef(evaluatedSourceAddress,
-                                              (size_t)evaluatedSourceLength);
+    evaluatedSource = llvm::MemoryBuffer::getMemBufferCopy(
+        {evaluatedSourceAddress, (size_t)evaluatedSourceLength});
+    free((void *)evaluatedSourceAddress);
     break;
 #else
     attachedTo->diagnose(diag::macro_unsupported);
@@ -1286,7 +1286,8 @@ evaluateAttachedMacro(MacroDecl *macro, Decl *attachedTo, CustomAttr *attr,
   // Create a new source buffer with the contents of the expanded macro.
   auto macroBuffer =
       llvm::MemoryBuffer::getMemBufferCopy(evaluatedSource, bufferName);
-  unsigned macroBufferID = sourceMgr.addNewSourceBuffer(std::move(macroBuffer));
+  unsigned macroBufferID =
+      sourceMgr.addNewSourceBuffer(std::move(evaluatedSource));
   auto macroBufferRange = sourceMgr.getRangeForBuffer(macroBufferID);
   GeneratedSourceInfo sourceInfo{
       generatedSourceKind,