From 6bd214af0bdbc3f3afe3459150da388f677eaa3c Mon Sep 17 00:00:00 2001
From: Ben Vanik <ben.vanik@gmail.com>
Date: Sat, 8 Feb 2014 22:01:51 -0800
Subject: [PATCH] Adding a shared scratch arena for compiler passes.

---
 src/alloy/compiler/compiler.cc      | 5 +++++
 src/alloy/compiler/compiler.h       | 2 ++
 src/alloy/compiler/compiler_pass.cc | 4 ++++
 src/alloy/compiler/compiler_pass.h  | 3 +++
 4 files changed, 14 insertions(+)

diff --git a/src/alloy/compiler/compiler.cc b/src/alloy/compiler/compiler.cc
index 07e786ade..a28f6b48b 100644
--- a/src/alloy/compiler/compiler.cc
+++ b/src/alloy/compiler/compiler.cc
@@ -20,6 +20,8 @@ using namespace alloy::runtime;
 
 Compiler::Compiler(Runtime* runtime) :
     runtime_(runtime) {
+  scratch_arena_ = new Arena();
+
   alloy::tracing::WriteEvent(EventType::Init({
   }));
 }
@@ -32,6 +34,8 @@ Compiler::~Compiler() {
     delete pass;
   }
 
+  delete scratch_arena_;
+
   alloy::tracing::WriteEvent(EventType::Deinit({
   }));
 }
@@ -49,6 +53,7 @@ int Compiler::Compile(HIRBuilder* builder) {
   //                 stop changing things, etc.
   for (auto it = passes_.begin(); it != passes_.end(); ++it) {
     CompilerPass* pass = *it;
+    scratch_arena_->Reset();
     if (pass->Run(builder)) {
       return 1;
     }
diff --git a/src/alloy/compiler/compiler.h b/src/alloy/compiler/compiler.h
index ae6b48455..d2874cceb 100644
--- a/src/alloy/compiler/compiler.h
+++ b/src/alloy/compiler/compiler.h
@@ -28,6 +28,7 @@ public:
   ~Compiler();
 
   runtime::Runtime* runtime() const { return runtime_; }
+  Arena* scratch_arena() const { return scratch_arena_; }
 
   void AddPass(CompilerPass* pass);
 
@@ -37,6 +38,7 @@ public:
 
 private:
   runtime::Runtime* runtime_;
+  Arena* scratch_arena_;
 
   typedef std::vector<CompilerPass*> PassList;
   PassList passes_;
diff --git a/src/alloy/compiler/compiler_pass.cc b/src/alloy/compiler/compiler_pass.cc
index 535bcb490..59f71902c 100644
--- a/src/alloy/compiler/compiler_pass.cc
+++ b/src/alloy/compiler/compiler_pass.cc
@@ -27,3 +27,7 @@ int CompilerPass::Initialize(Compiler* compiler) {
   compiler_ = compiler;
   return 0;
 }
+
+Arena* CompilerPass::scratch_arena() const {
+  return compiler_->scratch_arena();
+}
diff --git a/src/alloy/compiler/compiler_pass.h b/src/alloy/compiler/compiler_pass.h
index 1ed1b8144..4ba38b6c4 100644
--- a/src/alloy/compiler/compiler_pass.h
+++ b/src/alloy/compiler/compiler_pass.h
@@ -32,6 +32,9 @@ public:
 
   virtual int Run(hir::HIRBuilder* builder) = 0;
 
+protected:
+  Arena* scratch_arena() const;
+
 protected:
   runtime::Runtime* runtime_;
   Compiler* compiler_;