Add Builder::makeGlobal for nicer global creation (#1221)

Author: kripken

src/asm2wasm.h

@@ -33,6 +33,7 @@
 #include "parsing.h"
 #include "ast_utils.h"
 #include "ast/branch-utils.h"
+#include "ast/literal-utils.h"
 #include "ast/trapping.h"
 #include "wasm-builder.h"
 #include "wasm-emscripten.h"
@@ -392,17 +393,12 @@ class Asm2WasmBuilder {
   void allocateGlobal(IString name, WasmType type) {
     assert(mappedGlobals.find(name) == mappedGlobals.end());
     mappedGlobals.emplace(name, MappedGlobal(type));
-    auto global = new Global();
-    global->name = name;
-    global->type = type;
-    Literal value;
-    if (type == i32) value = Literal(uint32_t(0));
-    else if (type == f32) value = Literal(float(0));
-    else if (type == f64) value = Literal(double(0));
-    else WASM_UNREACHABLE();
-    global->init = wasm.allocator.alloc<Const>()->set(value);
-    global->mutable_ = true;
-    wasm.addGlobal(global);
+    wasm.addGlobal(builder.makeGlobal(
+      name,
+      type,
+      LiteralUtils::makeZero(type, wasm),
+      Builder::Mutable
+    ));
   }
 
   struct View {
@@ -838,12 +834,12 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
         // import an immutable and create a mutable global initialized to its value
         import->name = Name(std::string(import->name.str) + "$asm2wasm$import");
         {
-          auto global = new Global();
-          global->name = name;
-          global->type = type;
-          global->init = builder.makeGetGlobal(import->name, type);
-          global->mutable_ = true;
-          wasm.addGlobal(global);
+          wasm.addGlobal(builder.makeGlobal(
+            name,
+            type,
+            builder.makeGetGlobal(import->name, type),
+            Builder::Mutable
+          ));
         }
       }
     } else {
@@ -1076,11 +1072,12 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
           assert(pair[1]->isNumber());
           assert(exported.count(key) == 0);
           auto value = pair[1]->getInteger();
-          auto global = new Global();
-          global->name = key;
-          global->type = i32;
-          global->init = builder.makeConst(Literal(int32_t(value)));
-          global->mutable_ = false;
+          auto* global = builder.makeGlobal(
+            key,
+            i32,
+            builder.makeConst(Literal(int32_t(value))),
+            Builder::Immutable
+          );
           wasm.addGlobal(global);
           auto* export_ = new Export;
           export_->name = key;

src/passes/LegalizeJSInterface.cpp

@@ -30,6 +30,7 @@
 #include <pass.h>
 #include <wasm-builder.h>
 #include <ast_utils.h>
+#include <ast/literal-utils.h>
 
 namespace wasm {
 
@@ -226,12 +227,12 @@ struct LegalizeJSInterface : public Pass {
 
   void ensureTempRet0(Module* module) {
     if (!module->getGlobalOrNull(TEMP_RET_0)) {
-      Global* global = new Global;
-      global->name = TEMP_RET_0;
-      global->type = i32;
-      global->init = module->allocator.alloc<Const>()->set(Literal(int32_t(0)));
-      global->mutable_ = true;
-      module->addGlobal(global);
+      module->addGlobal(Builder::makeGlobal(
+        TEMP_RET_0,
+        i32,
+        LiteralUtils::makeZero(i32, *module),
+        Builder::Mutable
+      ));
     }
   }
 };

src/tools/translate-to-fuzz.h

@@ -180,11 +180,12 @@ class TranslateToFuzzReader {
     for (auto type : { i32, i64, f32, f64 }) {
       auto num = upTo(3);
       for (size_t i = 0; i < num; i++) {
-        auto* glob = new Global;
-        glob->name = std::string("global$") + std::to_string(index++);
-        glob->type = type;
-        glob->init = makeConst(type);
-        glob->mutable_ = true;
+        auto* glob = builder.makeGlobal(
+          std::string("global$") + std::to_string(index++),
+          type,
+          makeConst(type),
+          Builder::Mutable
+        );
         wasm.addGlobal(glob);
         globalsByType[type].push_back(glob->name);
       }
@@ -199,11 +200,12 @@ class TranslateToFuzzReader {
   const Name HANG_LIMIT_GLOBAL = "hangLimit";
 
   void addHangLimitSupport() {
-    auto* glob = new Global;
-    glob->name = HANG_LIMIT_GLOBAL;
-    glob->type = i32;
-    glob->init = builder.makeConst(Literal(int32_t(HANG_LIMIT)));
-    glob->mutable_ = true;
+    auto* glob = builder.makeGlobal(
+      HANG_LIMIT_GLOBAL,
+      i32,
+      builder.makeConst(Literal(int32_t(HANG_LIMIT))),
+      Builder::Mutable
+    );
     wasm.addGlobal(glob);
 
     auto* func = new Function;

src/wasm-builder.h

@@ -445,6 +445,21 @@ class Builder {
     return makeConst(value);
   }
 
+  // Module-level helpers
+
+  enum Mutability {
+    Mutable,
+    Immutable
+  };
+
+  static Global* makeGlobal(Name name, WasmType type, Expression* init, Mutability mutable_) {
+    auto* glob = new Global;
+    glob->name = name;
+    glob->type = type;
+    glob->init = init;
+    glob->mutable_ = mutable_ == Mutable;
+    return glob;
+  }
 };
 
 } // namespace wasm

src/wasm/wasm-binary.cpp

@@ -1823,14 +1823,16 @@ void WasmBinaryBuilder::readGlobals() {
   if (debug) std::cerr << "num: " << num << std::endl;
   for (size_t i = 0; i < num; i++) {
     if (debug) std::cerr << "read one" << std::endl;
-    auto curr = new Global;
-    curr->type = getWasmType();
+    auto type = getWasmType();
     auto mutable_ = getU32LEB();
     if (bool(mutable_) != mutable_) throw ParseException("Global mutability must be 0 or 1");
-    curr->mutable_ = mutable_;
-    curr->init = readExpression();
-    curr->name = Name("global$" + std::to_string(wasm.globals.size()));
-    wasm.addGlobal(curr);
+    auto* init = readExpression();
+    wasm.addGlobal(Builder::makeGlobal(
+      "global$" + std::to_string(wasm.globals.size()),
+      type,
+      init,
+      mutable_ ? Builder::Mutable : Builder::Immutable
+    ));
   }
 }