[llvm-branch-commits] [WebAssembly] Introduce CodeGenPassBuilder (PR #208983)

[Heejin Ahn via llvm-branch-commits]

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+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "WebAssembly.h"
+#include "WebAssemblyTargetMachine.h"
+#include "llvm/CodeGen/AtomicExpand.h"
+#include "llvm/CodeGen/IndirectBrExpand.h"
+#include "llvm/CodeGen/MachineBlockPlacement.h"
+#include "llvm/CodeGen/MachineCopyPropagation.h"
+#include "llvm/CodeGen/MachineLateInstrsCleanup.h"
+#include "llvm/CodeGen/PatchableFunction.h"
+#include "llvm/CodeGen/PostRAMachineSink.h"
+#include "llvm/CodeGen/PostRASchedulerList.h"
+#include "llvm/CodeGen/RegisterCoalescerPass.h"
+#include "llvm/CodeGen/RemoveLoadsIntoFakeUses.h"
+#include "llvm/CodeGen/ShrinkWrap.h"
+#include "llvm/CodeGen/UnreachableBlockElim.h"
+#include "llvm/IR/PassInstrumentation.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Passes/CodeGenPassBuilder.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Target/CGPassBuilderOption.h"
+#include "llvm/Transforms/Utils/LowerGlobalDtors.h"
+#include "llvm/Transforms/Utils/LowerInvoke.h"
+
+using namespace llvm;
+
+namespace WebAssembly {
+extern cl::opt<bool> WasmDisableExplicitLocals;
+extern cl::opt<bool> WasmEnableEH;
+extern cl::opt<bool> WasmEnableEmEH;
+extern cl::opt<bool> WasmEnableEmSjLj;
+extern cl::opt<bool> WasmEnableSjLj;
+} // namespace WebAssembly
+
+using llvm::WebAssembly::WasmDisableExplicitLocals;
+using llvm::WebAssembly::WasmEnableEH;
+using llvm::WebAssembly::WasmEnableEmEH;
+using llvm::WebAssembly::WasmEnableEmSjLj;
+using llvm::WebAssembly::WasmEnableSjLj;
+
+namespace {
+
+class WebAssemblyCodeGenPassBuilder
+    : public CodeGenPassBuilder<WebAssemblyCodeGenPassBuilder,
+                                WebAssemblyTargetMachine> {
+  using Base = CodeGenPassBuilder<WebAssemblyCodeGenPassBuilder,
+                                  WebAssemblyTargetMachine>;
+
+public:
+  explicit WebAssemblyCodeGenPassBuilder(WebAssemblyTargetMachine &TM,
+                                         const CGPassBuilderOption &Opts,
+                                         PassInstrumentationCallbacks *PIC)
+      : CodeGenPassBuilder(TM, Opts, PIC) {
+    disablePass<MachineLateInstrsCleanupPass, MachineCopyPropagationPass,
+                PostRAMachineSinkingPass, PostRASchedulerPass,
+                FuncletLayoutPass, StackMapLivenessPass, PatchableFunctionPass,
+                ShrinkWrapPass, RemoveLoadsIntoFakeUsesPass,
+                MachineBlockPlacementPass>();
+    if (getOptLevel() == CodeGenOptLevel::Less)
+      disablePass<RegisterCoalescerPass>();
+  }
+
+  void addIRPasses(PassManagerWrapper &PMW) const;
+  void addISelPrepare(PassManagerWrapper &PMW) const;
+  Error addInstSelector(PassManagerWrapper &PMW) const;
+  void addPreEmitPass(PassManagerWrapper &PMW) const;
+};
+
+void WebAssemblyCodeGenPassBuilder::addIRPasses(PassManagerWrapper &PMW) const {
+  // Add signatures to prototype-less function declarations
+  // TODO(boomanaiden154): WebAssemblyAddMissingPrototypes
+
+  // Lower .llvm.global_dtors into .llvm.global_ctors with __cxa_atexit calls.
+  flushFPMsToMPM(PMW);
----------------
aheejin wrote:

```suggestion
  flushFPMsToMPM(PMW);
  
  // Lower .llvm.global_dtors into .llvm.global_ctors with __cxa_atexit calls.
```
What does `flushFPMsToMPM` do? When do we call it?

https://github.com/llvm/llvm-project/pull/208983