[PM] Show the pass argument in pre/post-pass IR dumps

[nlguillemot]

Summary

This patch adds each pass' pass argument in the header for IR dumps.
For example:

Before:

*** IR Dump Before InstructionSelect ***

After:

*** IR Dump Before InstructionSelect (instruction-select) ***

The goal is to make it easier to know what argument to pass to
command line options like debug-only or run-pass to further
investigate a given pass.

[thegameg]

Thank you!

clang/test/Misc/pr32207.c

 // test for r305179
 // RUN: %clang_cc1 -emit-llvm -O2 -fno-experimental-new-pass-manager -mllvm -print-after-all %s -o %t 2>&1 | FileCheck %s
-// CHECK: *** IR Dump After Function Integration/Inlining ***
+// CHECK: *** IR Dump After Function Integration/Inlining (inline) ***
 void foo() {}

llvm/lib/IR/LegacyPassManager.cpp

if (ImmutablePass *IP = P->getAsImmutablePass()) {
     P->setResolver(AR);
     DM->initializeAnalysisImpl(P);
     addImmutablePass(IP);
     DM->recordAvailableAnalysis(IP);
     return;
   }
 
   if (PI && !PI->isAnalysis() && shouldPrintBeforePass(PI->getPassArgument())) {
-    Pass *PP = P->createPrinterPass(
-        dbgs(), ("*** IR Dump Before " + P->getPassName() + " ***").str());
+    Pass *PP =
+        P->createPrinterPass(dbgs(), ("*** IR Dump Before " + P->getPassName() +
+                                      " (" + PI->getPassArgument() + ") ***")
+                                         .str());
     PP->assignPassManager(activeStack, getTopLevelPassManagerType());
   }
 
   // Add the requested pass to the best available pass manager.
   P->assignPassManager(activeStack, getTopLevelPassManagerType());
 
   if (PI && !PI->isAnalysis() && shouldPrintAfterPass(PI->getPassArgument())) {
-    Pass *PP = P->createPrinterPass(
-        dbgs(), ("*** IR Dump After " + P->getPassName() + " ***").str());
+    Pass *PP =
+        P->createPrinterPass(dbgs(), ("*** IR Dump After " + P->getPassName() +
+                                      " (" + PI->getPassArgument() + ") ***")
+                                         .str());
     PP->assignPassManager(activeStack, getTopLevelPassManagerType());
   }
 }
 
 /// Find the pass that implements Analysis AID. Search immutable
 /// passes and all pass managers. If desired pass is not found
 /// then return NULL.
 Pass *PMTopLevelManager::findAnalysisPass(AnalysisID AID) {

llvm/test/CodeGen/SystemZ/frame-26.mir

 # RUN: llc -mtriple=s390x-linux-gnu -start-before=prologepilog %s -o - -print-after=prologepilog \
 # RUN:  -verify-machineinstrs 2>&1 | FileCheck %s
 # REQUIRES: asserts
 #
 # Test that R6 when used for an argument is modelled as being live throughout
 # the function when not saved in the prologue..
 
-# CHECK:      # *** IR Dump After Prologue/Epilogue Insertion & Frame Finalization ***:
+# CHECK:      # *** IR Dump After Prologue/Epilogue Insertion & Frame Finalization (prologepilog) ***:
 # CHECK-NEXT: # Machine code for function fun0:
 # CHECK-LABEL: bb.0:
 # CHECK: liveins:{{.*}} $r6d
 # CHECK: STMG killed $r7d, killed $r15d
 # CHECK: STG renamable $r6d
 # CHECK: End machine code for function fun0.
 
 

llvm/test/Transforms/Inline/null-function.ll

 ; RUN: opt -print-before=always-inline -always-inline -enable-new-pm=0 < %s -o /dev/null 2>&1 | FileCheck %s
 
 define i32 @main() #0 {
 entry:
   ret i32 0
 }
 
-; CHECK: *** IR Dump Before Inliner for always_inline functions ***
+; CHECK: *** IR Dump Before Inliner for always_inline functions (always-inline) ***
 ; CHECK: Printing <null> Function