[wasm] Replace WasmName by Vector<const char>

src/wasm/wasm-module.h

Index: src/wasm/wasm-module.h
diff --git a/src/wasm/wasm-module.h b/src/wasm/wasm-module.h
index 78b780ace04bb5b87898cf301f771a8f6aaa29ac..50a5860f9223a0975c7d59cfe6edc4e5488cf006 100644
--- a/src/wasm/wasm-module.h
+++ b/src/wasm/wasm-module.h
@@ -193,14 +193,18 @@ struct WasmModule {
   WasmName GetName(uint32_t offset, uint32_t length) const {
     if (length == 0) return {"<?>", 3};  // no name.
     CHECK(BoundsCheck(offset, offset + length));
-    return {reinterpret_cast<const char*>(module_start + offset), length};
+    DCHECK_EQ(static_cast<int64_t>(length), static_cast<int>(length));

[titzer, 2016/04/26 13:01:43]

Why is there an int64 in this DCHECK? Seems a little suspicious. Did you mean
uint32_t?

[Clemens Hammacher, 2016/04/26 13:12:21]

The check ensures that there is no int-overflow.
You can't really compare an uint32_t to a int32_t (a.k.a. int), so I compare the
zero-extended length with the sign-extended length. The lefthand side is
zero-extended to int64, the righthand side is sign-extended. Both should be
equal.

[titzer, 2016/04/26 13:16:11]

Might as well just DCHECK_GE(length, 0), as we assume that sizeof(int) >=
sizeof(uint32_t)

[Clemens Hammacher, 2016/04/26 13:20:09]

Yep, that's nicer. Changed it accordingly.

+    return {reinterpret_cast<const char*>(module_start + offset),
+            static_cast<int>(length)};
   }
 
   // Get a string stored in the module bytes representing a name.
   WasmName GetNameOrNull(uint32_t offset, uint32_t length) const {
     if (length == 0) return {NULL, 0};  // no name.
     CHECK(BoundsCheck(offset, offset + length));
-    return {reinterpret_cast<const char*>(module_start + offset), length};
+    DCHECK_EQ(static_cast<int64_t>(length), static_cast<int>(length));
+    return {reinterpret_cast<const char*>(module_start + offset),
+            static_cast<int>(length)};
   }
 
   // Checks the given offset range is contained within the module bytes.