[Pipelines] Do not run CoroSplit and CoroCleanup in LTO pre-link pipeline (llvm#100205)

This is re-land of llvm#90310 after making asan skip pre-split coroutines in
llvm#99415.

Skip CoroSplit and CoroCleanup in LTO pre-link pipeline so that
CoroElide can happen after callee coroutine is imported into caller's
module in ThinLTO.

Author: apolloww

clang/test/CodeGenCoroutines/coro-elide-thinlto.cpp

@@ -0,0 +1,78 @@
+// REQUIRES: x86_64-linux
+// This tests that the coroutine elide optimization could happen succesfully with ThinLTO.
+// This test is adapted from coro-elide.cpp and splits functions into two files.
+//
+// RUN: split-file %s %t
+// RUN: %clang --target=x86_64-linux -std=c++20 -O2 -flto=thin -I %S -c %t/coro-elide-callee.cpp -o coro-elide-callee.bc
+// RUN: %clang --target=x86_64-linux -std=c++20 -O2 -flto=thin -I %S -c %t/coro-elide-caller.cpp -o coro-elide-caller.bc
+// RUN: llvm-lto --thinlto coro-elide-callee.bc coro-elide-caller.bc -o summary
+// RUN: %clang_cc1 -O2 -x ir coro-elide-caller.bc -fthinlto-index=summary.thinlto.bc -emit-llvm -o - | FileCheck %s
+
+//--- coro-elide-task.h
+#pragma once
+#include "Inputs/coroutine.h"
+
+struct Task {
+  struct promise_type {
+    struct FinalAwaiter {
+      bool await_ready() const noexcept { return false; }
+      template <typename PromiseType>
+      std::coroutine_handle<> await_suspend(std::coroutine_handle<PromiseType> h) noexcept {
+        if (!h)
+          return std::noop_coroutine();
+        return h.promise().continuation;
+      }
+      void await_resume() noexcept {}
+    };
+    Task get_return_object() noexcept {
+      return std::coroutine_handle<promise_type>::from_promise(*this);
+    }
+    std::suspend_always initial_suspend() noexcept { return {}; }
+    FinalAwaiter final_suspend() noexcept { return {}; }
+    void unhandled_exception() noexcept {}
+    void return_value(int x) noexcept {
+      _value = x;
+    }
+    std::coroutine_handle<> continuation;
+    int _value;
+  };
+
+  Task(std::coroutine_handle<promise_type> handle) : handle(handle) {}
+  ~Task() {
+    if (handle)
+      handle.destroy();
+  }
+
+  struct Awaiter {
+    bool await_ready() const noexcept { return false; }
+    void await_suspend(std::coroutine_handle<void> continuation) noexcept {}
+    int await_resume() noexcept {
+      return 43;
+    }
+  };
+
+  auto operator co_await() {
+    return Awaiter{};
+  }
+
+private:
+  std::coroutine_handle<promise_type> handle;
+};
+
+//--- coro-elide-callee.cpp
+#include "coro-elide-task.h"
+Task task0() {
+  co_return 43;
+}
+
+//--- coro-elide-caller.cpp
+#include "coro-elide-task.h"
+
+Task task0();
+
+Task task1() {
+  co_return co_await task0();
+}
+
+// CHECK-LABEL: define{{.*}} void @_Z5task1v.resume
+// CHECK-NOT: {{.*}}_Znwm

llvm/lib/Passes/PassBuilderPipelines.cpp

@@ -979,7 +979,8 @@ PassBuilder::buildInlinerPipeline(OptimizationLevel Level,
   MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
       RequireAnalysisPass<ShouldNotRunFunctionPassesAnalysis, Function>()));
 
-  MainCGPipeline.addPass(CoroSplitPass(Level != OptimizationLevel::O0));
+  if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink)
+    MainCGPipeline.addPass(CoroSplitPass(Level != OptimizationLevel::O0));
 
   // Make sure we don't affect potential future NoRerun CGSCC adaptors.
   MIWP.addLateModulePass(createModuleToFunctionPassAdaptor(
@@ -1021,8 +1022,9 @@ PassBuilder::buildModuleInlinerPipeline(OptimizationLevel Level,
       buildFunctionSimplificationPipeline(Level, Phase),
       PTO.EagerlyInvalidateAnalyses));
 
-  MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
-      CoroSplitPass(Level != OptimizationLevel::O0)));
+  if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink)
+    MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
+        CoroSplitPass(Level != OptimizationLevel::O0)));
 
   return MPM;
 }
@@ -1219,7 +1221,8 @@ PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
   // and argument promotion.
   MPM.addPass(DeadArgumentEliminationPass());
 
-  MPM.addPass(CoroCleanupPass());
+  if (Phase != ThinOrFullLTOPhase::ThinLTOPreLink)
+    MPM.addPass(CoroCleanupPass());
 
   // Optimize globals now that functions are fully simplified.
   MPM.addPass(GlobalOptPass());

llvm/test/Other/new-pm-thinlto-prelink-defaults.ll

@@ -184,12 +184,10 @@
 ; CHECK-O-NEXT: Running pass: PostOrderFunctionAttrsPass
 ; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Running analysis: ShouldNotRunFunctionPassesAnalysis
-; CHECK-O-NEXT: Running pass: CoroSplitPass
 ; CHECK-O-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Invalidating analysis: ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Invalidating analysis: InlineAdvisorAnalysis
 ; CHECK-O-NEXT: Running pass: DeadArgumentEliminationPass
-; CHECK-O-NEXT: Running pass: CoroCleanupPass
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running pass: GlobalDCEPass
 ; CHECK-EXT: Running pass: {{.*}}::Bye

llvm/test/Other/new-pm-thinlto-prelink-pgo-defaults.ll

@@ -183,12 +183,10 @@
 ; CHECK-O-NEXT: Running pass: PostOrderFunctionAttrsPass
 ; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Running analysis: ShouldNotRunFunctionPassesAnalysis
-; CHECK-O-NEXT: Running pass: CoroSplitPass
 ; CHECK-O-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Invalidating analysis: ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Invalidating analysis: InlineAdvisorAnalysis
 ; CHECK-O-NEXT: Running pass: DeadArgumentEliminationPass
-; CHECK-O-NEXT: Running pass: CoroCleanupPass
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis on bar
 ; CHECK-O-NEXT: Running pass: GlobalDCEPass

llvm/test/Other/new-pm-thinlto-prelink-samplepgo-defaults.ll

@@ -148,12 +148,10 @@
 ; CHECK-O-NEXT: Running pass: PostOrderFunctionAttrsPass
 ; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Running analysis: ShouldNotRunFunctionPassesAnalysis
-; CHECK-O-NEXT: Running pass: CoroSplitPass
 ; CHECK-O-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Invalidating analysis: ShouldNotRunFunctionPassesAnalysis
 ; CHECK-O-NEXT: Invalidating analysis: InlineAdvisorAnalysis
 ; CHECK-O-NEXT: Running pass: DeadArgumentEliminationPass
-; CHECK-O-NEXT: Running pass: CoroCleanupPass
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running pass: GlobalDCEPass
 ; CHECK-O-NEXT: Running pass: AnnotationRemarksPass on foo