[PM] Support invalidation of inner analysis managers from a pass over the outer IR unit.

Summary:
This never really got implemented, and was very hard to test before
a lot of the refactoring changes to make things more robust. But now we
can test it thoroughly and cleanly, especially at the CGSCC level.

The core idea is that when an inner analysis manager proxy receives the
invalidation event for the outer IR unit, it needs to walk the inner IR
units and propagate it to the inner analysis manager for each of those
units. For example, each function in the SCC needs to get an
invalidation event when the SCC gets one.

The function / module interaction is somewhat boring here. This really
becomes interesting in the face of analysis-backed IR units. This patch
effectively handles all of the CGSCC layer's needs -- both invalidating
SCC analysis and invalidating function analysis when an SCC gets
invalidated.

However, this second aspect doesn't really handle the
LoopAnalysisManager well at this point. That one will need some change
of design in order to fully integrate, because unlike the call graph,
the entire function behind a LoopAnalysis's results can vanish out from
under us, and we won't even have a cached API to access. I'd like to try
to separate solving the loop problems into a subsequent patch though in
order to keep this more focused so I've adapted them to the API and
updated the tests that immediately fail, but I've not added the level of
testing and validation at that layer that I have at the CGSCC layer.

An important aspect of this change is that the proxy for the
FunctionAnalysisManager at the SCC pass layer doesn't work like the
other proxies for an inner IR unit as it doesn't directly manage the
FunctionAnalysisManager and invalidation or clearing of it. This would
create an ever worsening problem of dual ownership of this
responsibility, split between the module-level FAM proxy and this
SCC-level FAM proxy. Instead, this patch changes the SCC-level FAM proxy
to work in terms of the module-level proxy and defer to it to handle
much of the updates. It only does SCC-specific invalidation. This will
become more important in subsequent patches that support more complex
invalidaiton scenarios.

Reviewers: jlebar

Subscribers: mehdi_amini, mcrosier, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D27197

llvm-svn: 289317

1 files changed, 15 insertions, 25 deletions

diff --git a/llvm/unittests/IR/PassManagerTest.cpp b/llvm/unittests/IR/PassManagerTest.cpp
index 2b977b464ad..d7515ba6b7d 100644
--- a/llvm/unittests/IR/PassManagerTest.cpp
+++ b/llvm/unittests/IR/PassManagerTest.cpp
@@ -91,19 +91,6 @@ struct TestPreservingModulePass : PassInfoMixin<TestPreservingModulePass> {
   }
 };
 
-struct TestMinPreservingModulePass
-    : PassInfoMixin<TestMinPreservingModulePass> {
-  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM) {
-    PreservedAnalyses PA;
-
-    // Force running an analysis.
-    (void)AM.getResult<TestModuleAnalysis>(M);
-
-    PA.preserve<FunctionAnalysisManagerModuleProxy>();
-    return PA;
-  }
-};
-
 struct TestFunctionPass : PassInfoMixin<TestFunctionPass> {
   TestFunctionPass(int &RunCount, int &AnalyzedInstrCount,
                    int &AnalyzedFunctionCount,
@@ -215,11 +202,11 @@ TEST_F(PassManagerTest, BasicPreservedAnalyses) {
 }
 
 TEST_F(PassManagerTest, Basic) {
-  FunctionAnalysisManager FAM;
+  FunctionAnalysisManager FAM(/*DebugLogging*/ true);
   int FunctionAnalysisRuns = 0;
   FAM.registerPass([&] { return TestFunctionAnalysis(FunctionAnalysisRuns); });
 
-  ModuleAnalysisManager MAM;
+  ModuleAnalysisManager MAM(/*DebugLogging*/ true);
   int ModuleAnalysisRuns = 0;
   MAM.registerPass([&] { return TestModuleAnalysis(ModuleAnalysisRuns); });
   MAM.registerPass([&] { return FunctionAnalysisManagerModuleProxy(FAM); });
@@ -233,11 +220,11 @@ TEST_F(PassManagerTest, Basic) {
   int AnalyzedFunctionCount1 = 0;
   {
     // Pointless scoped copy to test move assignment.
-    ModulePassManager NestedMPM;
+    ModulePassManager NestedMPM(/*DebugLogging*/ true);
     FunctionPassManager FPM;
     {
       // Pointless scope to test move assignment.
-      FunctionPassManager NestedFPM;
+      FunctionPassManager NestedFPM(/*DebugLogging*/ true);
       NestedFPM.addPass(TestFunctionPass(
           FunctionPassRunCount1, AnalyzedInstrCount1, AnalyzedFunctionCount1));
       FPM = std::move(NestedFPM);
@@ -255,7 +242,7 @@ TEST_F(PassManagerTest, Basic) {
   int AnalyzedInstrCount2 = 0;
   int AnalyzedFunctionCount2 = 0;
   {
-    FunctionPassManager FPM;
+    FunctionPassManager FPM(/*DebugLogging*/ true);
     FPM.addPass(TestFunctionPass(FunctionPassRunCount2, AnalyzedInstrCount2,
                                  AnalyzedFunctionCount2));
     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
@@ -268,15 +255,16 @@ TEST_F(PassManagerTest, Basic) {
   int AnalyzedInstrCount3 = 0;
   int AnalyzedFunctionCount3 = 0;
   {
-    FunctionPassManager FPM;
+    FunctionPassManager FPM(/*DebugLogging*/ true);
     FPM.addPass(TestFunctionPass(FunctionPassRunCount3, AnalyzedInstrCount3,
                                  AnalyzedFunctionCount3));
     FPM.addPass(TestInvalidationFunctionPass("f"));
     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
   }
 
-  // A fourth function pass manager but with a minimal intervening passes.
-  MPM.addPass(TestMinPreservingModulePass());
+  // A fourth function pass manager but with only preserving intervening
+  // passes but triggering the module analysis.
+  MPM.addPass(RequireAnalysisPass<TestModuleAnalysis, Module>());
   int FunctionPassRunCount4 = 0;
   int AnalyzedInstrCount4 = 0;
   int AnalyzedFunctionCount4 = 0;
@@ -287,12 +275,13 @@ TEST_F(PassManagerTest, Basic) {
     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
   }
 
-  // A fifth function pass manager but which uses only cached results.
+  // A fifth function pass manager which invalidates one function first but
+  // uses only cached results.
   int FunctionPassRunCount5 = 0;
   int AnalyzedInstrCount5 = 0;
   int AnalyzedFunctionCount5 = 0;
   {
-    FunctionPassManager FPM;
+    FunctionPassManager FPM(/*DebugLogging*/ true);
     FPM.addPass(TestInvalidationFunctionPass("f"));
     FPM.addPass(TestFunctionPass(FunctionPassRunCount5, AnalyzedInstrCount5,
                                  AnalyzedFunctionCount5,
@@ -317,16 +306,17 @@ TEST_F(PassManagerTest, Basic) {
   EXPECT_EQ(0, AnalyzedFunctionCount3);
   EXPECT_EQ(3, FunctionPassRunCount4);
   EXPECT_EQ(5, AnalyzedInstrCount4);
-  EXPECT_EQ(0, AnalyzedFunctionCount4);
+  EXPECT_EQ(9, AnalyzedFunctionCount4);
   EXPECT_EQ(3, FunctionPassRunCount5);
   EXPECT_EQ(2, AnalyzedInstrCount5); // Only 'g' and 'h' were cached.
-  EXPECT_EQ(0, AnalyzedFunctionCount5);
+  EXPECT_EQ(9, AnalyzedFunctionCount5);
 
   // Validate the analysis counters:
   //   first run over 3 functions, then module pass invalidates
   //   second run over 3 functions, nothing invalidates
   //   third run over 0 functions, but 1 function invalidated
   //   fourth run over 1 function
+  //   fifth run invalidates 1 function first, but runs over 0 functions
   EXPECT_EQ(7, FunctionAnalysisRuns);
 
   EXPECT_EQ(1, ModuleAnalysisRuns);