[llvm] faf5210 - [CGSCC] Add -abort-on-max-devirt-iterations-reached option

[Arthur Eubanks via llvm-commits]

Author: Arthur Eubanks
Date: 2020-10-16T12:34:52-07:00
New Revision: faf521042098f3780a8b12698260833d9c980b62

URL: https://github.com/llvm/llvm-project/commit/faf521042098f3780a8b12698260833d9c980b62
DIFF: https://github.com/llvm/llvm-project/commit/faf521042098f3780a8b12698260833d9c980b62.diff

LOG: [CGSCC] Add -abort-on-max-devirt-iterations-reached option

Aborts if we hit the max devirtualization iteration.
Will be useful for testing that changes to devirtualization don't cause
devirtualization to repeat passes more times than necessary.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D89519

Added: 
    

Modified: 
    llvm/include/llvm/Analysis/CGSCCPassManager.h
    llvm/lib/Analysis/CGSCCPassManager.cpp
    llvm/test/Other/cgscc-devirt-iteration.ll

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Analysis/CGSCCPassManager.h b/llvm/include/llvm/Analysis/CGSCCPassManager.h
index d3489284ceec..755bc92ddccf 100644
--- a/llvm/include/llvm/Analysis/CGSCCPassManager.h
+++ b/llvm/include/llvm/Analysis/CGSCCPassManager.h
@@ -559,6 +559,10 @@ createCGSCCToFunctionPassAdaptor(FunctionPassT Pass) {
   return CGSCCToFunctionPassAdaptor<FunctionPassT>(std::move(Pass));
 }
 
+/// Checks -abort-on-max-devirt-iterations-reached to see if we should report an
+/// error.
+void maxDevirtIterationsReached();
+
 /// A helper that repeats an SCC pass each time an indirect call is refined to
 /// a direct call by that pass.
 ///
@@ -711,6 +715,7 @@ class DevirtSCCRepeatedPass
 
       // Otherwise, if we've already hit our max, we're done.
       if (Iteration >= MaxIterations) {
+        maxDevirtIterationsReached();
         LLVM_DEBUG(
             dbgs() << "Found another devirtualization after hitting the max "
                       "number of repetitions ("

diff  --git a/llvm/lib/Analysis/CGSCCPassManager.cpp b/llvm/lib/Analysis/CGSCCPassManager.cpp
index 468b00234ba6..61c03f9bddfa 100644
--- a/llvm/lib/Analysis/CGSCCPassManager.cpp
+++ b/llvm/lib/Analysis/CGSCCPassManager.cpp
@@ -21,9 +21,11 @@
 #include "llvm/IR/PassManager.h"
 #include "llvm/IR/PassManagerImpl.h"
 #include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/TimeProfiler.h"
+#include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
 #include <iterator>
@@ -36,6 +38,11 @@ using namespace llvm;
 // template typedefs.
 namespace llvm {
 
+static cl::opt<bool> AbortOnMaxDevirtIterationsReached(
+    "abort-on-max-devirt-iterations-reached",
+    cl::desc("Abort when the max iterations for devirtualization CGSCC repeat "
+             "pass is reached"));
+
 // Explicit instantiations for the core proxy templates.
 template class AllAnalysesOn<LazyCallGraph::SCC>;
 template class AnalysisManager<LazyCallGraph::SCC, LazyCallGraph &>;
@@ -362,6 +369,11 @@ static void updateNewSCCFunctionAnalyses(LazyCallGraph::SCC &C,
   }
 }
 
+void llvm::maxDevirtIterationsReached() {
+  if (AbortOnMaxDevirtIterationsReached)
+    report_fatal_error("Max devirtualization iterations reached");
+}
+
 /// Helper function to update both the \c CGSCCAnalysisManager \p AM and the \c
 /// CGSCCPassManager's \c CGSCCUpdateResult \p UR based on a range of newly
 /// added SCCs.

diff  --git a/llvm/test/Other/cgscc-devirt-iteration.ll b/llvm/test/Other/cgscc-devirt-iteration.ll
index 3fcb332b4aa9..9a5a2a79d65f 100644
--- a/llvm/test/Other/cgscc-devirt-iteration.ll
+++ b/llvm/test/Other/cgscc-devirt-iteration.ll
@@ -8,6 +8,9 @@
 ; RUN: opt -aa-pipeline=basic-aa -passes='cgscc(devirt<1>(function-attrs,function(gvn,instcombine)))' -S < %s | FileCheck %s --check-prefix=CHECK --check-prefix=AFTER --check-prefix=AFTER1
 ; RUN: opt -aa-pipeline=basic-aa -passes='cgscc(devirt<2>(function-attrs,function(gvn,instcombine)))' -S < %s | FileCheck %s --check-prefix=CHECK --check-prefix=AFTER --check-prefix=AFTER2
 ;
+; RUN: not --crash opt -abort-on-max-devirt-iterations-reached -aa-pipeline=basic-aa -passes='cgscc(devirt<1>(function-attrs,function(gvn,instcombine)))' -S < %s
+; RUN: opt -abort-on-max-devirt-iterations-reached -aa-pipeline=basic-aa -passes='cgscc(devirt<2>(function-attrs,function(gvn,instcombine)))' -S < %s
+;
 ; We also verify that the real O2 pipeline catches these cases.
 ; RUN: opt -aa-pipeline=basic-aa -passes='default<O2>' -S < %s | FileCheck %s --check-prefix=CHECK --check-prefix=AFTER --check-prefix=AFTER2