[PATCH] D105606: [Coroutine] Record the elided coroutines

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu created this revision.
ChuanqiXu added reviewers: lxfind, rjmccall.
Herald added a subscriber: hiraditya.
ChuanqiXu requested review of this revision.
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Herald added a subscriber: llvm-commits.

This is follow up for D105095 <https://reviews.llvm.org/D105095>. In D105095 <https://reviews.llvm.org/D105095>, we recorded how many coroutine got elided.
Then in practice, it is helpful to know the accurate coroutine got elided.

I think it is helpful for others who use a large projects.

Test Plan: check-llvm


https://reviews.llvm.org/D105606

Files:
  llvm/lib/Transforms/Coroutines/CoroElide.cpp
  llvm/test/Transforms/Coroutines/coro-elide-count.ll
  llvm/test/Transforms/Coroutines/coro-elide-stat.ll


Index: llvm/test/Transforms/Coroutines/coro-elide-stat.ll
===================================================================
--- llvm/test/Transforms/Coroutines/coro-elide-stat.ll
+++ llvm/test/Transforms/Coroutines/coro-elide-stat.ll
@@ -4,8 +4,15 @@
 ; RUN: opt < %s -S \
 ; RUN:   -passes='cgscc(repeat<2>(inline,function(coro-elide,dce)))' -stats 2>&1 \
 ; RUN:   | FileCheck %s
+; RUN: opt < %s --disable-output \
+; RUN:   -passes='cgscc(repeat<2>(inline,function(coro-elide,dce)))' \
+; RUN:   -coro-elide-info-output-file=%t && \
+; RUN:  cat %t \
+; RUN:   | FileCheck %s --check-prefix=FILE
 
 ; CHECK: 2 coro-elide  - The # of coroutine get elided.
+; FILE: Elide f in callResume
+; FILE: Elide f in callResumeMultiRetDommmed
 
 declare void @print(i32) nounwind
 
Index: llvm/lib/Transforms/Coroutines/CoroElide.cpp
===================================================================
--- llvm/lib/Transforms/Coroutines/CoroElide.cpp
+++ llvm/lib/Transforms/Coroutines/CoroElide.cpp
@@ -17,6 +17,7 @@
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
 
 using namespace llvm;
 
@@ -24,6 +25,10 @@
 
 STATISTIC(NumOfCoroElided, "The # of coroutine get elided.");
 
+static cl::opt<std::string> CoroElideInfoOutputFilename(
+    "coro-elide-info-output-file", cl::value_desc("filename"),
+    cl::desc("File to record the coroutines got elided"), cl::Hidden);
+
 namespace {
 // Created on demand if the coro-elide pass has work to do.
 struct Lowerer : coro::LowererBase {
@@ -122,6 +127,21 @@
   llvm_unreachable("no terminator in the entry block");
 }
 
+#ifndef NDEBUG
+static std::unique_ptr<raw_fd_ostream> getOrCreateLogFile() {
+  assert(!CoroElideInfoOutputFilename.empty() &&
+         "coro-elide-info-output-file shouldn't be empty");
+  std::error_code EC;
+  auto Result = std::make_unique<raw_fd_ostream>(CoroElideInfoOutputFilename,
+                                                 EC, sys::fs::OF_Append);
+  if (!EC)
+    return Result;
+  llvm::errs() << "Error opening coro-elide-info-output-file '"
+               << CoroElideInfoOutputFilename << " for appending!\n";
+  return std::make_unique<raw_fd_ostream>(2, false); // stderr.
+}
+#endif
+
 // To elide heap allocations we need to suppress code blocks guarded by
 // llvm.coro.alloc and llvm.coro.free instructions.
 void Lowerer::elideHeapAllocations(Function *F, uint64_t FrameSize,
@@ -348,6 +368,13 @@
                          FrameSizeAndAlign.second, AA);
     coro::replaceCoroFree(CoroId, /*Elide=*/true);
     NumOfCoroElided++;
+#ifndef NDEBUG
+    if (!CoroElideInfoOutputFilename.empty()) {
+      auto outputFile = getOrCreateLogFile();
+      *outputFile << "Elide " << CoroId->getCoroutine()->getName() << " in "
+                  << CoroId->getFunction()->getName() << "\n";
+    }
+#endif
   }
 
   return true;


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