refactor arena code

3 files changed, 38 insertions, 44 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index 65d837496..2d045401a 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -1,6 +1,7 @@
 
 #include "wasm.h"
 #include "optimizer.h"
+#include "mixed_arena.h"
 
 namespace wasm {
 
@@ -69,7 +70,7 @@ std::vector<Ref> AstStackHelper::astStack;
 class Asm2WasmBuilder {
   Module& wasm;
 
-  wasm::Arena allocator;
+  MixedArena allocator;
 
   // globals
 
@@ -307,8 +308,6 @@ private:
     return -1; // avoid warning
   }
 
-  wasm::Arena tempAllocator;
-
   std::map<unsigned, Ref> tempNums;
 
   Literal getLiteral(Ref ast) {
@@ -503,10 +502,6 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
   for (auto curr : toErase) {
     wasm.imports.erase(curr);
   }
-
-  // cleanups
-
-  tempAllocator.clear();
 }
 
 Function* Asm2WasmBuilder::processFunction(Ref ast) {
@@ -1063,8 +1058,6 @@ void Asm2WasmBuilder::optimize() {
   // Optimization passes. Note: no effort is made to free nodes that are no longer held on to.
 
   struct BlockBreakOptimizer : public WasmWalker {
-    BlockBreakOptimizer() : WasmWalker(nullptr) {}
-
     void visitBlock(Block *curr) override {
       // if the block ends in a break on this very block, then just put the value there
       Break *last = curr->list[curr->list.size()-1]->dyn_cast<Break>();
diff --git a/src/mixed_arena.h b/src/mixed_arena.h
new file mode 100644
index 000000000..a92026580
--- /dev/null
+++ b/src/mixed_arena.h
@@ -0,0 +1,35 @@
+
+#include <vector>
+
+// Arena allocation for mixed-type data.
+struct MixedArena {
+  std::vector<char*> chunks;
+  int index; // in last chunk
+
+  template<class T>
+  T* alloc() {
+    const size_t CHUNK = 10000;
+    size_t currSize = (sizeof(T) + 7) & (-8); // same alignment as malloc TODO optimize?
+    assert(currSize < CHUNK);
+    if (chunks.size() == 0 || index + currSize >= CHUNK) {
+      chunks.push_back(new char[CHUNK]);
+      index = 0;
+    }
+    T* ret = (T*)(chunks.back() + index);
+    index += currSize;
+    new (ret) T();
+    return ret;
+  }
+
+  void clear() {
+    for (char* chunk : chunks) {
+      delete[] chunk;
+    }
+    chunks.clear();
+  }
+
+  ~MixedArena() {
+    clear();
+  }
+};
+
diff --git a/src/wasm.h b/src/wasm.h
index ecf44e72e..1fce6692b 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -18,38 +18,6 @@ namespace wasm {
 
 // Utilities
 
-// Arena allocation for mixed-type data.
-struct Arena {
-  std::vector<char*> chunks;
-  int index; // in last chunk
-
-  template<class T>
-  T* alloc() {
-    const size_t CHUNK = 10000;
-    size_t currSize = (sizeof(T) + 7) & (-8); // same alignment as malloc TODO optimize?
-    assert(currSize < CHUNK);
-    if (chunks.size() == 0 || index + currSize >= CHUNK) {
-      chunks.push_back(new char[CHUNK]);
-      index = 0;
-    }
-    T* ret = (T*)(chunks.back() + index);
-    index += currSize;
-    new (ret) T();
-    return ret;
-  }
-
-  void clear() {
-    for (char* chunk : chunks) {
-      delete[] chunk;
-    }
-    chunks.clear();
-  }
-
-  ~Arena() {
-    clear();
-  }
-};
-
 std::ostream &doIndent(std::ostream &o, unsigned indent) {
   for (unsigned i = 0; i < indent; i++) {
     o << "  ";
@@ -1004,11 +972,9 @@ std::ostream& Expression::print(std::ostream &o, unsigned indent) {
 //
 
 struct WasmWalker : public WasmVisitor<void> {
-  wasm::Arena* allocator; // use an existing allocator, or null if no allocations
   Expression* replace;
 
-  WasmWalker() : allocator(nullptr), replace(nullptr) {}
-  WasmWalker(wasm::Arena* allocator) : allocator(allocator), replace(nullptr) {}
+  WasmWalker() : replace(nullptr) {}
 
   // the visit* methods can call this to replace the current node
   void replaceCurrent(Expression *expression) {