commit 250fc9c859fdeed3f200ae911a7e7ea338f38436
author Douglas Gregor <dgregor@apple.com> Sat Apr 18 00:07:54 2009 +0000
committer Douglas Gregor <dgregor@apple.com> Sat Apr 18 00:07:54 2009 +0000
tree e296b134cdb17a030e1c368397575060d5b60bcb
parent 7297134f128423fce2e88f92421ed135bded7d4e

Lazy deserialization of function bodies for PCH files. For the Carbon
"Hello, World!", this takes us from deserializing 6469
statements/expressions down to deserializing 1
statement/expression. It only translated into a 1% improvement on the
Carbon-prefixed 403.gcc, but (a) it's the right thing to do, and (b)
we expect this to matter more once we lazily deserialize identifiers.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69407 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AST/Decl.cpp

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 5d49d70..8bda323 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -308,8 +308,8 @@
 //===----------------------------------------------------------------------===//
 
 void FunctionDecl::Destroy(ASTContext& C) {
-  if (Body)
-    Body->Destroy(C);
+  if (Body && Body.isOffset())
+    Body.get(C.getExternalSource())->Destroy(C);
 
   for (param_iterator I=param_begin(), E=param_end(); I!=E; ++I)
     (*I)->Destroy(C);
@@ -325,7 +325,7 @@
   for (const FunctionDecl *FD = this; FD != 0; FD = FD->PreviousDeclaration) {
     if (FD->Body) {
       Definition = FD;
-      return cast<CompoundStmt>(FD->Body);
+      return cast<CompoundStmt>(FD->Body.get(Context.getExternalSource()));
     }
   }
 
@@ -334,8 +334,9 @@
 
 CompoundStmt *FunctionDecl::getBodyIfAvailable() const {
   for (const FunctionDecl *FD = this; FD != 0; FD = FD->PreviousDeclaration) {
-    if (FD->Body)
-      return cast<CompoundStmt>(FD->Body);
+    if (FD->Body && !FD->Body.isOffset()) {
+      return cast<CompoundStmt>(FD->Body.get(0));
+    }
   }
 
   return 0;

lib/Frontend/PCHReader.cpp

diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index 5ea1f7c..dc8d3fc 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -140,7 +140,7 @@
 void PCHDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
   VisitValueDecl(FD);
   if (Record[Idx++])
-    FD->setBody(cast<CompoundStmt>(Reader.ReadStmt()));
+    FD->setLazyBody(Reader.getStream().GetCurrentBitNo());
   FD->setPreviousDeclaration(
                    cast_or_null<FunctionDecl>(Reader.GetDecl(Record[Idx++])));
   FD->setStorageClass((FunctionDecl::StorageClass)Record[Idx++]);
@@ -1880,6 +1880,15 @@
   return ReadDeclRecord(DeclOffsets[Index], Index);
 }
 
+Stmt *PCHReader::GetStmt(uint64_t Offset) {
+  // Keep track of where we are in the stream, then jump back there
+  // after reading this declaration.
+  SavedStreamPosition SavedPosition(Stream);
+
+  Stream.JumpToBit(Offset);
+  return ReadStmt();
+}
+
 bool PCHReader::ReadDeclsLexicallyInContext(DeclContext *DC,
                                   llvm::SmallVectorImpl<pch::DeclID> &Decls) {
   assert(DC->hasExternalLexicalStorage() &&