Only enable AddDiscriminator pass when -fdebug-info-for-profiling is true

[danielcdh]

Summary

AddDiscriminator pass is only useful for sample pgo. This patch restricts AddDiscriminator to -fdebug-info-for-profiling so that it does not introduce unecessary debug size increases for non-sample-pgo builds.

[dblaikie]

Did you want to enable all DebugInfoForProfiling features when there's a sample profile specified? (not sure if all of the features are needed when stitching things back up, or if some of them are only needed for emission/tracking purposes)

[danielcdh]

update

[danielcdh]

You are right, only discriminator is needed, the encoding and emission part should be orthogonal. Patch updated.

lib/CodeGen/BackendUtil.cpp

void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 
   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
 
   if (TM)
     TM->adjustPassManager(PMBuilder);
 
+  if (CodeGenOpts.DebugInfoForProfiling ||
+      !CodeGenOpts.SampleProfileFile.empty())
     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
                            addAddDiscriminatorsPass);
 
   // In ObjC ARC mode, add the main ARC optimization passes.
   if (LangOpts.ObjCAutoRefCount) {
     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
                            addObjCARCExpandPass);
     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
                            addObjCARCAPElimPass);
     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,

test/CodeGenObjC/arc-linetable-autorelease.m

 - (NSBezierPath *)_createBezierPathWithWidth:(CGFloat)width height:(CGFloat)height radius:(CGFloat)radius lineWidth:(CGFloat)lineWidth
 {
   NSRect rect = NSMakeRect(0, 0, width, height);
   NSBezierPath *path = [NSBezierPath bezierPathWithRoundedRect:rect xRadius:radius yRadius:radius];
   CGFloat pattern[2];
   // CHECK: define {{.*}}_createBezierPathWithWidth
   // CHECK: load {{.*}} %path, align {{.*}}, !dbg ![[RET:[0-9]+]]
   // CHECK: call void @objc_storeStrong{{.*}} !dbg ![[ARC:[0-9]+]]
-  // CHECK: call {{.*}} @objc_autoreleaseReturnValue{{.*}} !dbg ![[ARC1:[0-9]+]]
+  // CHECK: call {{.*}} @objc_autoreleaseReturnValue{{.*}} !dbg ![[ARC]]
   // CHECK: ret {{.*}} !dbg ![[ARC]]
   // CHECK: ![[RET]] = !DILocation(line: [[@LINE+1]], scope: !{{.*}})
   return path;
-  // CHECK: ![[ARC]] = !DILocation(line: [[@LINE+2]], scope: !{{.*}})
-  // CHECK: ![[ARC1]] = !DILocation(line: [[@LINE+1]], scope: !{{.*}})
+  // CHECK: ![[ARC]] = !DILocation(line: [[@LINE+1]], scope: !{{.*}})
 }
 @end