From 97bb0bdacbb8ccd59aca116c66f0f43f322aebaa Mon Sep 17 00:00:00 2001
From: Alon Zakai <azakai@google.com>
Date: Wed, 26 Jan 2022 11:10:26 -0800
Subject: Remove NoExitRuntime pass (#4431)

After emscripten-core/emscripten#15905 lands Emscripten will no longer use it,
and nothing else needs it AFAIK.
---
 src/passes/CMakeLists.txt    |  1 -
 src/passes/NoExitRuntime.cpp | 65 --------------------------------------------
 src/passes/pass.cpp          |  4 ---
 src/passes/passes.h          |  1 -
 4 files changed, 71 deletions(-)
 delete mode 100644 src/passes/NoExitRuntime.cpp

(limited to 'src')

diff --git a/src/passes/CMakeLists.txt b/src/passes/CMakeLists.txt
index e24072424..7e5960d4b 100644
--- a/src/passes/CMakeLists.txt
+++ b/src/passes/CMakeLists.txt
@@ -58,7 +58,6 @@ set(passes_SOURCES
   MinifyImportsAndExports.cpp
   NameList.cpp
   NameTypes.cpp
-  NoExitRuntime.cpp
   OnceReduction.cpp
   OptimizeAddedConstants.cpp
   OptimizeInstructions.cpp
diff --git a/src/passes/NoExitRuntime.cpp b/src/passes/NoExitRuntime.cpp
deleted file mode 100644
index e15ef81bc..000000000
--- a/src/passes/NoExitRuntime.cpp
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- * Copyright 2016 WebAssembly Community Group participants
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-//
-// Assumes the program will never exit the runtime (as in the emscripten
-// NO_EXIT_RUNTIME option). That means that atexit()s do not need to be
-// run.
-//
-
-#include <asmjs/shared-constants.h>
-#include <pass.h>
-#include <wasm-builder.h>
-#include <wasm.h>
-
-namespace wasm {
-
-struct NoExitRuntime : public WalkerPass<PostWalker<NoExitRuntime>> {
-  bool isFunctionParallel() override { return true; }
-
-  Pass* create() override { return new NoExitRuntime; }
-
-  // Remove all possible manifestations of atexit, across llvm wasm
-  // backend.
-  std::array<Name, 4> ATEXIT_NAMES = {
-    {"___cxa_atexit", "__cxa_atexit", "_atexit", "atexit"}};
-
-  void visitCall(Call* curr) {
-    auto* import = getModule()->getFunctionOrNull(curr->target);
-    if (!import || !import->imported() || import->module != ENV) {
-      return;
-    }
-    for (auto name : ATEXIT_NAMES) {
-      if (name == import->base) {
-        // Remove the call, and drop the arguments (which may have side
-        // effects); let other passes clean that up more.
-        Builder builder(*getModule());
-        std::vector<Expression*> args;
-        for (auto* operand : curr->operands) {
-          args.push_back(builder.makeDrop(operand));
-        }
-        // Ensure the block has the right type using the last arg.
-        args.push_back(builder.replaceWithIdenticalType(curr));
-        replaceCurrent(builder.makeBlock(args));
-        break;
-      }
-    }
-  }
-};
-
-Pass* createNoExitRuntimePass() { return new NoExitRuntime(); }
-
-} // namespace wasm
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index 99288cc6e..9158f22dd 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -251,10 +251,6 @@ void PassRegistry::registerPasses() {
                createModAsyncifyNeverUnwindPass);
   registerPass("nm", "name list", createNameListPass);
   registerPass("name-types", "(re)name all heap types", createNameTypesPass);
-  registerPass("no-exit-runtime",
-               "removes calls to atexit(), which is valid if the C runtime "
-               "will never be exited",
-               createNoExitRuntimePass);
   registerPass("once-reduction",
                "reduces calls to code that only runs once",
                createOnceReductionPass);
diff --git a/src/passes/passes.h b/src/passes/passes.h
index 0e72bb518..501edccc7 100644
--- a/src/passes/passes.h
+++ b/src/passes/passes.h
@@ -79,7 +79,6 @@ Pass* createMinifyImportsAndExportsAndModulesPass();
 Pass* createMetricsPass();
 Pass* createNameListPass();
 Pass* createNameTypesPass();
-Pass* createNoExitRuntimePass();
 Pass* createOnceReductionPass();
 Pass* createOptimizeAddedConstantsPass();
 Pass* createOptimizeAddedConstantsPropagatePass();
-- 
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