[RISCV] Collect Statistics on Compressed Instructions

Summary:
It is useful to keep statistics on how many instructions we have
compressed, so we can see if future changes are increasing or decreasing this
number.

Reviewers: asb, luismarques

Reviewed By: asb, luismarques

Subscribers: xbolva00, sameer.abuasal, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67495

Author: lenary

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -15,6 +15,7 @@
 #include "Utils/RISCVMatInt.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/CodeGen/Register.h"
 #include "llvm/MC/MCAssembler.h"
@@ -37,10 +38,15 @@
 
 using namespace llvm;
 
+#define DEBUG_TYPE "riscv-asm-parser"
+
 // Include the auto-generated portion of the compress emitter.
 #define GEN_COMPRESS_INSTR
 #include "RISCVGenCompressInstEmitter.inc"
 
+STATISTIC(RISCVNumInstrsCompressed,
+          "Number of RISC-V Compressed instructions emitted");
+
 namespace {
 struct RISCVOperand;
 
@@ -1615,6 +1621,8 @@ bool RISCVAsmParser::parseDirectiveOption() {
 void RISCVAsmParser::emitToStreamer(MCStreamer &S, const MCInst &Inst) {
   MCInst CInst;
   bool Res = compressInst(CInst, Inst, getSTI(), S.getContext());
+  if (Res)
+    ++RISCVNumInstrsCompressed;
   S.EmitInstruction((Res ? CInst : Inst), getSTI());
 }
 

llvm/lib/Target/RISCV/RISCVAsmPrinter.cpp

@@ -16,6 +16,7 @@
 #include "MCTargetDesc/RISCVMCExpr.h"
 #include "RISCVTargetMachine.h"
 #include "TargetInfo/RISCVTargetInfo.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
@@ -31,6 +32,9 @@ using namespace llvm;
 
 #define DEBUG_TYPE "asm-printer"
 
+STATISTIC(RISCVNumInstrsCompressed,
+          "Number of RISC-V Compressed instructions emitted");
+
 namespace {
 class RISCVAsmPrinter : public AsmPrinter {
 public:
@@ -64,6 +68,8 @@ void RISCVAsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
   MCInst CInst;
   bool Res = compressInst(CInst, Inst, *TM.getMCSubtargetInfo(),
                           OutStreamer->getContext());
+  if (Res)
+    ++RISCVNumInstrsCompressed;
   AsmPrinter::EmitToStreamer(*OutStreamer, Res ? CInst : Inst);
 }