From b83450ed1fd98cec4453024f57f892b31851ea50 Mon Sep 17 00:00:00 2001
From: Thomas Lively <tlively@google.com>
Date: Tue, 11 Oct 2022 11:16:14 -0500
Subject: Make `Name` a pointer, length pair (#5122)

With the goal of supporting null characters (i.e. zero bytes) in strings.
Rewrite the underlying interned `IString` to store a `std::string_view` rather
than a `const char*`, reduce the number of map lookups necessary to intern a
string, and present a more immutable interface.

Most importantly, replace the `c_str()` method that returned a `const char*`
with a `toString()` method that returns a `std::string`. This new method can
correctly handle strings containing null characters. A `const char*` can still
be had by calling `data()` on the `std::string_view`, although this usage should
be discouraged.

This change is NFC in spirit, although not in practice. It does not intend to
support any particular new functionality, but it is probably now possible to use
strings containing null characters in at least some cases. At least one parser
bug is also incidentally fixed. Follow-on PRs will explicitly support and test
strings containing nulls for particular use cases.

The C API still uses `const char*` to represent strings. As strings containing
nulls become better supported by the rest of Binaryen, this will no longer be
sufficient. Updating the C and JS APIs to use pointer, length pairs is left as
future work.
---
 src/tools/wasm2js.cpp | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

(limited to 'src/tools/wasm2js.cpp')

diff --git a/src/tools/wasm2js.cpp b/src/tools/wasm2js.cpp
index 7cecb5f6d..a6430fe12 100644
--- a/src/tools/wasm2js.cpp
+++ b/src/tools/wasm2js.cpp
@@ -834,7 +834,7 @@ void AssertionEmitter::emit() {
   )";
 
   Builder wasmBuilder(sexpBuilder.getModule());
-  Name asmModule = std::string("ret") + ASM_FUNC.str;
+  Name asmModule = std::string("ret") + ASM_FUNC.toString();
   // Track the last built module.
   Module wasm;
   for (size_t i = 0; i < root.size(); ++i) {
@@ -843,11 +843,11 @@ void AssertionEmitter::emit() {
         e[0]->str() == Name("module")) {
       ModuleUtils::clearModule(wasm);
       std::stringstream funcNameS;
-      funcNameS << ASM_FUNC.c_str() << i;
+      funcNameS << ASM_FUNC << i;
       std::stringstream moduleNameS;
-      moduleNameS << "ret" << ASM_FUNC.c_str() << i;
-      Name funcName(funcNameS.str().c_str());
-      asmModule = Name(moduleNameS.str().c_str());
+      moduleNameS << "ret" << ASM_FUNC << i;
+      Name funcName(funcNameS.str());
+      asmModule = Name(moduleNameS.str());
       options.applyFeatures(wasm);
       SExpressionWasmBuilder builder(wasm, e, options.profile);
       emitWasm(wasm, out, flags, options.passOptions, funcName);
@@ -857,13 +857,13 @@ void AssertionEmitter::emit() {
       std::cerr << "skipping " << e << std::endl;
       continue;
     }
-    Name testFuncName(IString(("check" + std::to_string(i)).c_str(), false));
+    Name testFuncName("check" + std::to_string(i));
     bool isInvoke = (e[0]->str() == Name("invoke"));
     bool isReturn = (e[0]->str() == Name("assert_return"));
     bool isReturnNan = (e[0]->str() == Name("assert_return_nan"));
     if (isInvoke) {
       emitInvokeFunc(wasmBuilder, wasm, e, testFuncName, asmModule);
-      out << testFuncName.str << "();\n";
+      out << testFuncName << "();\n";
       continue;
     }
     // Otherwise, this is some form of assertion.
@@ -875,7 +875,7 @@ void AssertionEmitter::emit() {
       emitAssertTrapFunc(wasmBuilder, wasm, e, testFuncName, asmModule);
     }
 
-    out << "if (!" << testFuncName.str << "()) throw 'assertion failed: " << e
+    out << "if (!" << testFuncName << "()) throw 'assertion failed: " << e
         << "';\n";
   }
 }
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