[PM/PGO] Wire up the opt driver's new PM support to be able to run PGO.

[chandlerc]

Summary

This lets us run the only test in the tree that uses the entire
instrumentation PGO pipeline (rather than a direct pass test) on both
the new PM as well as the old one. We could probably use more tests of
the semantically important parts of this pipeline (as evidenced by the
DCE bug I just fixed) but this at least is a start and makes sure the
core of the new PM's pipeline does actually support PGO.

[davidxl]

tools/opt/NewPMDriver.cpp

52

-> Enable profiling generating instrumentation

58

Enable LLVM instrumentation for generating profile into the specified file.

[davide]

LGTM with David's comments addressed.

[davide]

Trying to catch up on reviews.
Chandler, was this ever committed?

test/Transforms/PGOProfile/preinline.ll

 ; RUN: opt < %s -O2 -profile-generate -S | FileCheck %s --check-prefix=GEN
 ; RUN: opt < %s -O2 -profile-generate -profile-generate-file=default.profraw -S | FileCheck %s --check-prefix=GEN
+
+; RUN: opt < %s -passes='default<O2>' -new-pm-profile-generate -S | FileCheck %s --check-prefix=GEN
+; RUN: opt < %s -passes='default<O2>' -new-pm-profile-generate-file=default.profraw -S | FileCheck %s --check-prefix=GEN
+
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 define i32 @foo(i32 %i) {
 entry:
 ; GEN: %pgocount = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc_foo
 ; GEN-NOT: %pgocount.i = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__stdin__bar
   %call = call i32 @bar()

tools/opt/NewPMDriver.cpp

 // use when querying for aliasing information. It only works in concert with
 // the "passes" flag above.
 static cl::opt<std::string>
     AAPipeline("aa-pipeline",
                cl::desc("A textual description of the alias analysis "
                         "pipeline for handling managed aliasing queries"),
                cl::Hidden);
 
+static cl::opt<bool>
+    RunProfileGen("new-pm-profile-generate", cl::init(false), cl::Hidden,
+                  cl::desc("Enable generating an instrumentation-based profile "
+                           "with the new pass manager."));
+
+static cl::opt<std::string> ProfileGenFile(
+    "new-pm-profile-generate-file", cl::init(""), cl::Hidden,
+    cl::value_desc("filename"),
+    cl::desc("Enable generating an instrumentation-based profile with the new "
+             "pass manager and write it to the specified file."));
+
+static cl::opt<std::string> ProfileUseFile(
+    "new-pm-profile-use", cl::init(""), cl::Hidden, cl::value_desc("filename"),
+    cl::desc("Enable using an instrumentation-based profile with the new "
+             "pass manager and the given file."));
+
 bool llvm::runPassPipeline(StringRef Arg0, Module &M,
                            TargetMachine *TM, tool_output_file *Out,
                            StringRef PassPipeline, OutputKind OK,
                            VerifierKind VK,
                            bool ShouldPreserveAssemblyUseListOrder,
                            bool ShouldPreserveBitcodeUseListOrder,
                            bool EmitSummaryIndex, bool EmitModuleHash) {
-  PassBuilder PB(TM);
+  // Handle any PGO options.
+  Optional<PGOOptions> PGOOpts = None;
+  if (RunProfileGen || !ProfileGenFile.empty()) {
+    if (!ProfileUseFile.empty()) {
+      errs() << Arg0 << ": cannot generate and use a profile in the same invocation.\n";
+      return false;
+    }
+
+    PGOOpts = PGOOptions();
+    PGOOpts->ProfileGenFile = ProfileGenFile;
+    PGOOpts->RunProfileGen = true;
+  } else if (!ProfileUseFile.empty()) {
+    PGOOpts = PGOOptions();
+    PGOOpts->ProfileUseFile = ProfileUseFile;
+  }
+
+  PassBuilder PB(TM, PGOOpts);
 
   // Specially handle the alias analysis manager so that we can register
   // a custom pipeline of AA passes with it.
   AAManager AA;
   if (!PB.parseAAPipeline(AA, AAPipeline)) {
     errs() << Arg0 << ": unable to parse AA pipeline description.\n";
     return false;
   }