[AsmPrinter] Use getMnemonic for instruction-mix remark.

[fhahn]

Summary

This patch uses the new getMnemonic helper from D90039
to display mnemonics instead of the internal opcodes.

The main motivation behind using the mnemonics is that they
are more user-friendly and more directly related to the assembly
the users will be presented.

[fhahn]

rebase

[fhahn]

Update the count by mnemonics

[fhahn]

Document getMnemonic

[fhahn]

Rebase & ping :)

[fhahn]

ping :)

[paquette]

llvm/include/llvm/MC/MCStreamer.h

457

Would it make sense to make this return an Optional to make it clear that this may not necessarily return a mnemonic?

[arsenm]

llvm/include/llvm/MC/MCStreamer.h

457

empty string works well enough

[paquette]

llvm/include/llvm/MC/MCStreamer.h

457

yeah you're probably right

[paquette]

LGTM

[fhahn]

llvm/include/llvm/MC/MCStreamer.h

457

Thanks, I clarified the comment to mention when "" is returned. it should be easy to adjust, if there's a need or use case where Optional is more convenient.

llvm/include/llvm/MC/MCStreamer.h

public:
   MCSymbol *endSection(MCSection *Section);
 
   /// Sets the symbol's section.
   ///
   /// Each emitted symbol will be tracked in the ordering table,
   /// so we can sort on them later.
   void AssignFragment(MCSymbol *Symbol, MCFragment *Fragment);
 
+  /// Returns the mnemonic for \p MI, if the streamer has
+  /// access to a instruction printer.
+  virtual StringRef getMnemonic(MCInst &MI) { return ""; }
+
   /// Emit a label for \p Symbol into the current section.
   ///
   /// This corresponds to an assembler statement such as:
   ///   foo:
   ///
   /// \param Symbol - The symbol to emit. A given symbol should only be
   /// emitted as a label once, and symbols emitted as a label should never be
   /// used in an assignment.

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

if (isVerbose()) {
     }
   }
 
   // Print out code for the function.
   bool HasAnyRealCode = false;
   int NumInstsInFunction = 0;
 
   bool CanDoExtraAnalysis = ORE->allowExtraAnalysis(DEBUG_TYPE);
-  const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
   for (auto &MBB : *MF) {
     // Print a label for the basic block.
     emitBasicBlockStart(MBB);
-    DenseMap<unsigned, unsigned> OpcodeCounts;
+    DenseMap<StringRef, unsigned> MnemonicCounts;
     for (auto &MI : MBB) {
       // Print the assembly for the instruction.
       if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
           !MI.isDebugInstr()) {
         HasAnyRealCode = true;
         ++NumInstsInFunction;
       }
 
for (auto &MI : MBB) {
         if (isVerbose()) emitImplicitDef(&MI);
         break;
       case TargetOpcode::KILL:
         if (isVerbose()) emitKill(&MI, *this);
         break;
       default:
         emitInstruction(&MI);
         if (CanDoExtraAnalysis) {
-          auto I = OpcodeCounts.insert({MI.getOpcode(), 0u});
+          MCInst MCI;
+          MCI.setOpcode(MI.getOpcode());
+          auto Name = OutStreamer->getMnemonic(MCI);
+          auto I = MnemonicCounts.insert({Name, 0u});
           I.first->second++;
         }
         break;
       }
 
       // If there is a post-instruction symbol, emit a label for it here.
       if (MCSymbol *S = MI.getPostInstrSymbol())
         OutStreamer->emitLabel(S);
for (auto &MBB : *MF) {
     if (CanDoExtraAnalysis) {
       // Skip empty blocks.
       if (MBB.empty())
         continue;
 
       MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionMix",
                                           MBB.begin()->getDebugLoc(), &MBB);
 
-      // Generate instruction mix remark. First, convert opcodes to string
-      // names, then sort them in descending order by count and name.
-      SmallVector<std::pair<std::string, unsigned>, 128> OpcodeCountsVec;
-      for (auto &KV : OpcodeCounts) {
-        auto Name = (Twine("INST_") + TII->getName(KV.first)).str();
-        OpcodeCountsVec.emplace_back(Name, KV.second);
-      }
-      sort(OpcodeCountsVec, [](const std::pair<std::string, unsigned> &A,
-                               const std::pair<std::string, unsigned> &B) {
+      // Generate instruction mix remark. First, sort counts in descending order
+      // by count and name.
+      SmallVector<std::pair<StringRef, unsigned>, 128> MnemonicVec;
+      for (auto &KV : MnemonicCounts)
+        MnemonicVec.emplace_back(KV.first, KV.second);
+
+      sort(MnemonicVec, [](const std::pair<StringRef, unsigned> &A,
+                           const std::pair<StringRef, unsigned> &B) {
         if (A.second > B.second)
           return true;
         if (A.second == B.second)
-          return A.first < B.first;
+          return StringRef(A.first) < StringRef(B.first);
         return false;
       });
       R << "BasicBlock: " << ore::NV("BasicBlock", MBB.getName()) << "\n";
-      for (auto &KV : OpcodeCountsVec)
-        R << KV.first << ": " << ore::NV(KV.first, KV.second) << "\n";
+      for (auto &KV : MnemonicVec) {
+        auto Name = (Twine("INST_") + KV.first.trim()).str();
+        R << KV.first << ": " << ore::NV(Name, KV.second) << "\n";
+      }
       ORE->emit(R);
     }
   }
 
   EmittedInsts += NumInstsInFunction;
   MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount",
                                       MF->getFunction().getSubprogram(),
                                       &MF->front());

llvm/lib/MC/MCAsmStreamer.cpp

public:
   /// @{
 
   void changeSection(MCSection *Section, const MCExpr *Subsection) override;
 
   void emitELFSymverDirective(StringRef AliasName,
                               const MCSymbol *Aliasee) override;
 
   void emitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override;
+
+  StringRef getMnemonic(MCInst &MI) override {
+    return InstPrinter->getMnemonic(&MI).first;
+  }
+
   void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
 
   void emitAssemblerFlag(MCAssemblerFlag Flag) override;
   void emitLinkerOptions(ArrayRef<std::string> Options) override;
   void emitDataRegion(MCDataRegionType Kind) override;
   void emitVersionMin(MCVersionMinType Kind, unsigned Major, unsigned Minor,
                       unsigned Update, VersionTuple SDKVersion) override;
   void emitBuildVersion(unsigned Platform, unsigned Major, unsigned Minor,

llvm/test/CodeGen/AArch64/arm64-instruction-mix-remarks.ll

 ; RUN: llc -mtriple=arm64-apple-ios7.0 -pass-remarks-output=%t -pass-remarks=asm-printer -o - %s | FileCheck %s
 ; RUN: FileCheck --input-file=%t --check-prefix=YAML %s
 
 ; CHECK-LABEL: %entry
 ; CHECK-NEXT:   ldr w8, [x0]
+; CHECK-NEXT:   mov w10, #16959
+; CHECK-NEXT:   movk w10, #15, lsl #16
 ; CHECK-NEXT:   add w8, w8, w1
-; CHECK-NEXT:   cmp w8, #100
+; CHECK-NEXT:   add x9, x8, x2
+; CHECK-NEXT:   cmp x9, x10
 ; CHECK-NEXT:   b.ne    LBB0_2
 
 ; YAML:      Name:            InstructionMix
 ; YAML-NEXT: DebugLoc:        { File: arm64-instruction-mix-remarks.ll, Line: 10, Column: 10 }
 ; YAML-NEXT: Function:        foo
 ; YAML-NEXT: Args:
-; YAML:      - BasicBlock:      entry
-; YAML:      - INST_ADDWrs:     '1'
-; YAML:      - INST_Bcc:        '1'
-; YAML:      - INST_LDRWui:     '1'
-; YAML:      - INST_SUBSWri:    '1'
+; YAML:      - BasicBlock:  entry
+; YAML:      - INST_add:    '2'
+; YAML:      - INST_b.:     '1'
+; YAML:      - INST_ldr:    '1'
+; YAML:      - INST_movk:   '1'
+; YAML:      - INST_movz:   '1'
+; YAML:      - INST_subs:   '1'
 
 
 ; CHECK-LABEL: %then
 ; CHECK-NEXT:    mov w0, w8
 ; CHECK-NEXT:    ret
 
 ; YAML:      Name:            InstructionMix
 ; YAML-NEXT: DebugLoc:        { File: arm64-instruction-mix-remarks.ll, Line: 20, Column: 20 }
 ; YAML-NEXT: Function:        foo
 ; YAML-NEXT: Args:
-; YAML:        - BasicBlock:      then
-; YAML:        - INST_ORRWrs:     '1'
-; YAML:        - INST_RET:        '1'
+; YAML:        - BasicBlock: then
+; YAML:        - INST_orr:   '1'
+; YAML:        - INST_ret:   '1'
 
 ; CHECK-LABEL: %else
 ; CHECK-NEXT:    mul w8, w8, w1
 ; CHECK-NEXT:    mov w9, #10
 ; CHECK-NEXT:    mul w8, w8, w1
 ; CHECK-NEXT:    str w9, [x0]
 ; CHECK-NEXT:    mov w0, w8
 ; CHECK-NEXT:    ret
 
 ; YAML:      Name:            InstructionMix
 ; YAML-NEXT: DebugLoc:        { File: arm64-instruction-mix-remarks.ll, Line: 30, Column: 30 }
 ; YAML-NEXT: Function:        foo
 ; YAML-NEXT: Args:
-; YAML:       - BasicBlock:      else
-; YAML:       - INST_MADDWrrr:   '2'
-; YAML:       - INST_ORRWrs:     '1'
-; YAML:       - INST_RET:        '1'
-; YAML:       - INST_STRWui:     '1'
-define i32 @foo(i32* %ptr, i32 %x) !dbg !3 {
+; YAML:       - BasicBlock:  else
+; YAML:       - INST_madd:   '2'
+; YAML:       - INST_orr:    '1'
+; YAML:       - INST_ret:    '1'
+; YAML:       - INST_str:    '1'
+define i32 @foo(i32* %ptr, i32 %x, i64 %y) !dbg !3 {
 entry:
   %l = load i32, i32* %ptr, !dbg !4
   %add = add i32 %l, %x, !dbg !4
-  %c = icmp eq i32 %add, 100, !dbg !4
+  %add.ext = zext i32 %add to i64, !dbg !4
+  %add.64 = add i64 %add.ext, %y, !dbg !4
+  %c = icmp eq i64 %add.64, 999999, !dbg !4
   br i1 %c, label %then, label %else, !dbg !4
 
 then:
   ret i32 %add, !dbg !5
 
 else:
   store i32 10, i32* %ptr, !dbg !6
   %res = mul i32 %add, %x, !dbg !6