[NPM] Added opt option -print-pipeline-passes.

Added opt option -print-pipeline-passes to print a -passes compatible
string describing the built pass pipeline.

As an example:
$ opt -enable-new-pm=1 -adce -licm -simplifycfg -o /dev/null /dev/null -print-pipeline-passes
verify,function(adce),function(loop-mssa(licm)),function(simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-sink-common-insts>),verify,BitcodeWriterPass

At the moment this is best-effort only and there are some known
limitations:
- Not all passes accepting parameters will print their parameters
  (currently only implemented for simplifycfg).
- Some ClassName to pass-name mappings are not unique.
- Some ClassName to pass-name mappings are missing (e.g.
  BitcodeWriterPass).

Differential Revision: https://reviews.llvm.org/D108298

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp
index 9f61aa0..1794d053 100644
--- a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp
@@ -44,6 +44,18 @@ PassManager<Loop, LoopAnalysisManager, LoopStandardAnalysisResults &,
   return PA;
 }
 
+void PassManager<Loop, LoopAnalysisManager, LoopStandardAnalysisResults &,
+                 LPMUpdater &>::printPipeline(raw_ostream &OS,
+                                              function_ref<StringRef(StringRef)>
+                                                  MapClassName2PassName) {
+  for (unsigned Idx = 0, Size = LoopPasses.size(); Idx != Size; ++Idx) {
+    auto *P = LoopPasses[Idx].get();
+    P->printPipeline(OS, MapClassName2PassName);
+    if (Idx + 1 < Size)
+      OS << ",";
+  }
+}
+
 // Run both loop passes and loop-nest passes on top-level loop \p L.
 PreservedAnalyses
 LoopPassManager::runWithLoopNestPasses(Loop &L, LoopAnalysisManager &AM,
@@ -172,6 +184,12 @@ LoopPassManager::runWithoutLoopNestPasses(Loop &L, LoopAnalysisManager &AM,
 }
 } // namespace llvm
 
+void FunctionToLoopPassAdaptor::printPipeline(
+    raw_ostream &OS, function_ref<StringRef(StringRef)> MapClassName2PassName) {
+  OS << (UseMemorySSA ? "loop-mssa(" : "loop(");
+  Pass->printPipeline(OS, MapClassName2PassName);
+  OS << ")";
+}
 PreservedAnalyses FunctionToLoopPassAdaptor::run(Function &F,
                                                  FunctionAnalysisManager &AM) {
   // Before we even compute any loop analyses, first run a miniature function