[MCA] Add flag -show-encoding to llvm-mca.
Flag -show-encoding enables the printing of instruction encodings as part of the
the instruction info view.
Example (with flags -mtriple=x86_64-- -mcpu=btver2):
Instruction Info:
[1]: #uOps
[2]: Latency
[3]: RThroughput
[4]: MayLoad
[5]: MayStore
[6]: HasSideEffects (U)
[7]: Encoding Size
[1] [2] [3] [4] [5] [6] [7] Encodings: Instructions:
1 2 1.00 4 c5 f0 59 d0 vmulps %xmm0, %xmm1, %xmm2
1 4 1.00 4 c5 eb 7c da vhaddps %xmm2, %xmm2, %xmm3
1 4 1.00 4 c5 e3 7c e3 vhaddps %xmm3, %xmm3, %xmm4
In this example, column Encoding Size is the size in bytes of the instruction
encoding. Column Encodings reports the actual instruction encodings as byte
sequences in hex (objdump style).
The computation of encodings is done by a utility class named mca::CodeEmitter.
In future, I plan to expose the CodeEmitter to the instruction builder, so that
information about instruction encoding sizes can be used by the simulator. That
would be a first step towards simulating the throughput from the decoders in the
hardware frontend.
Differential Revision: https://reviews.llvm.org/D65948
llvm-svn: 368432
diff --git a/llvm/docs/CommandGuide/llvm-mca.rst b/llvm/docs/CommandGuide/llvm-mca.rst
index f2ebbec..4f8704a 100644
--- a/llvm/docs/CommandGuide/llvm-mca.rst
+++ b/llvm/docs/CommandGuide/llvm-mca.rst
@@ -174,6 +174,10 @@
Enable the instruction info view. This is enabled by default.
+.. option:: -show-encoding
+
+ Enable the printing of instruction encodings within the instruction info view.
+
.. option:: -all-stats
Print all hardware statistics. This enables extra statistics related to the
@@ -415,10 +419,10 @@
resources, and the *Resource pressure view* can help to identify the problematic
resource usage.
-The second section of the report shows the latency and reciprocal
-throughput of every instruction in the sequence. That section also reports
-extra information related to the number of micro opcodes, and opcode properties
-(i.e., 'MayLoad', 'MayStore', and 'HasSideEffects').
+The second section of the report is the `instruction info view`. It shows the
+latency and reciprocal throughput of every instruction in the sequence. It also
+reports extra information related to the number of micro opcodes, and opcode
+properties (i.e., 'MayLoad', 'MayStore', and 'HasSideEffects').
Field *RThroughput* is the reciprocal of the instruction throughput. Throughput
is computed as the maximum number of instructions of a same type that can be
@@ -427,6 +431,31 @@
cycles/instruction. That is because the FP multiplier JFPM is only available
from pipeline JFPU1.
+Instruction encodings are displayed within the instruction info view when flag
+`-show-encoding` is specified.
+
+Below is an example of `-show-encoding` output for the dot-product kernel:
+
+.. code-block:: none
+
+ Instruction Info:
+ [1]: #uOps
+ [2]: Latency
+ [3]: RThroughput
+ [4]: MayLoad
+ [5]: MayStore
+ [6]: HasSideEffects (U)
+ [7]: Encoding Size
+
+ [1] [2] [3] [4] [5] [6] [7] Encodings: Instructions:
+ 1 2 1.00 4 c5 f0 59 d0 vmulps %xmm0, %xmm1, %xmm2
+ 1 4 1.00 4 c5 eb 7c da vhaddps %xmm2, %xmm2, %xmm3
+ 1 4 1.00 4 c5 e3 7c e3 vhaddps %xmm3, %xmm3, %xmm4
+
+The `Encoding Size` column shows the size in bytes of instructions. The
+`Encodings` column shows the actual instruction encodings (byte sequences in
+hex).
+
The third section is the *Resource pressure view*. This view reports
the average number of resource cycles consumed every iteration by instructions
for every processor resource unit available on the target. Information is
diff --git a/llvm/include/llvm/MCA/CodeEmitter.h b/llvm/include/llvm/MCA/CodeEmitter.h
new file mode 100644
index 0000000..c8d222b
--- /dev/null
+++ b/llvm/include/llvm/MCA/CodeEmitter.h
@@ -0,0 +1,72 @@
+//===--------------------- CodeEmitter.h ------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// A utility class used to compute instruction encodings. It buffers encodings
+/// for later usage. It exposes a simple API to compute and get the encodings as
+/// StringRef.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MCA_CODEEMITTER_H
+#define LLVM_MCA_CODEEMITTER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCFixup.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MCA/Instruction.h"
+#include "llvm/MCA/Support.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <string>
+
+namespace llvm {
+namespace mca {
+
+/// A utility class used to compute instruction encodings for a code region.
+///
+/// It provides a simple API to compute and return instruction encodings as
+/// strings. Encodings are cached internally for later usage.
+class CodeEmitter {
+ const MCSubtargetInfo &STI;
+ const MCAsmBackend &MAB;
+ const MCCodeEmitter &MCE;
+
+ SmallString<256> Code;
+ raw_svector_ostream VecOS;
+ ArrayRef<MCInst> Sequence;
+
+ // An EncodingInfo pair stores <base, length> information. Base (i.e. first)
+ // is an index to the `Code`. Length (i.e. second) is the encoding size.
+ using EncodingInfo = std::pair<unsigned, unsigned>;
+
+ // A cache of encodings.
+ SmallVector<EncodingInfo, 16> Encodings;
+
+ EncodingInfo getOrCreateEncodingInfo(unsigned MCID);
+
+public:
+ CodeEmitter(const MCSubtargetInfo &ST, const MCAsmBackend &AB,
+ const MCCodeEmitter &CE, ArrayRef<MCInst> S)
+ : STI(ST), MAB(AB), MCE(CE), VecOS(Code), Sequence(S),
+ Encodings(S.size()) {}
+
+ StringRef getEncoding(unsigned MCID) {
+ EncodingInfo EI = getOrCreateEncodingInfo(MCID);
+ return StringRef(&Code[EI.first], EI.second);
+ }
+};
+
+} // namespace mca
+} // namespace llvm
+
+#endif // LLVM_MCA_CODEEMITTER_H
diff --git a/llvm/lib/MCA/CMakeLists.txt b/llvm/lib/MCA/CMakeLists.txt
index 4965b6b..e2eb06e 100644
--- a/llvm/lib/MCA/CMakeLists.txt
+++ b/llvm/lib/MCA/CMakeLists.txt
@@ -1,4 +1,5 @@
add_llvm_library(LLVMMCA
+ CodeEmitter.cpp
Context.cpp
HWEventListener.cpp
HardwareUnits/HardwareUnit.cpp
diff --git a/llvm/lib/MCA/CodeEmitter.cpp b/llvm/lib/MCA/CodeEmitter.cpp
new file mode 100644
index 0000000..2941072
--- /dev/null
+++ b/llvm/lib/MCA/CodeEmitter.cpp
@@ -0,0 +1,37 @@
+//===--------------------- CodeEmitter.cpp ----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the CodeEmitter API.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MCA/CodeEmitter.h"
+
+namespace llvm {
+namespace mca {
+
+CodeEmitter::EncodingInfo
+CodeEmitter::getOrCreateEncodingInfo(unsigned MCID) {
+ EncodingInfo &EI = Encodings[MCID];
+ if (EI.second)
+ return EI;
+
+ SmallVector<llvm::MCFixup, 2> Fixups;
+ const MCInst &Inst = Sequence[MCID];
+ MCInst Relaxed(Sequence[MCID]);
+ if (MAB.mayNeedRelaxation(Inst, STI))
+ MAB.relaxInstruction(Inst, STI, Relaxed);
+
+ EI.first = Code.size();
+ MCE.encodeInstruction(Relaxed, VecOS, Fixups, STI);
+ EI.second = Code.size() - EI.first;
+ return EI;
+}
+
+} // namespace mca
+} // namespace llvm
diff --git a/llvm/test/tools/llvm-mca/X86/show-encoding.s b/llvm/test/tools/llvm-mca/X86/show-encoding.s
new file mode 100644
index 0000000..1a81bdf
--- /dev/null
+++ b/llvm/test/tools/llvm-mca/X86/show-encoding.s
@@ -0,0 +1,77 @@
+# NOTE: Assertions have been autogenerated by utils/update_mca_test_checks.py
+# RUN: llvm-mca -mtriple=x86_64-unknown-unknown -mcpu=btver2 -all-views=false -instruction-info < %s | FileCheck %s --check-prefix=NORMAL
+# RUN: llvm-mca -mtriple=x86_64-unknown-unknown -mcpu=btver2 -all-views=false -instruction-info -show-encoding=false < %s | FileCheck %s --check-prefix=NORMAL
+# RUN: llvm-mca -mtriple=x86_64-unknown-unknown -mcpu=btver2 -all-views=false -instruction-info -show-encoding < %s | FileCheck %s --check-prefix=WITHENCODINGS
+
+ movq 0x170(%rbp), %r10
+ lea (%r8,%r8,2), %r9d
+ movsx %r9d, %r9
+ inc %r8d
+ movq 0x178(%rbp), %r11
+ vmovups (%r10,%r9,4), %xmm3
+ vpslldq $0x4, %xmm3, %xmm2
+ vpslldq $0x4, %xmm3, %xmm4
+ vaddps %xmm2, %xmm3, %xmm6
+ vpslldq $0xc, %xmm3, %xmm5
+ vaddps %xmm4, %xmm5, %xmm7
+ vaddps %xmm6, %xmm7, %xmm8
+ vaddps %xmm8, %xmm0, %xmm9
+ vshufps $0xff, %xmm9, %xmm9, %xmm0
+ vmovups %xmm9, (%r11,%r9,4)
+ cmp %r8d, %esi
+ jl -90
+
+# NORMAL: Instruction Info:
+# NORMAL-NEXT: [1]: #uOps
+# NORMAL-NEXT: [2]: Latency
+# NORMAL-NEXT: [3]: RThroughput
+# NORMAL-NEXT: [4]: MayLoad
+# NORMAL-NEXT: [5]: MayStore
+# NORMAL-NEXT: [6]: HasSideEffects (U)
+
+# WITHENCODINGS: Instruction Info:
+# WITHENCODINGS-NEXT: [1]: #uOps
+# WITHENCODINGS-NEXT: [2]: Latency
+# WITHENCODINGS-NEXT: [3]: RThroughput
+# WITHENCODINGS-NEXT: [4]: MayLoad
+# WITHENCODINGS-NEXT: [5]: MayStore
+# WITHENCODINGS-NEXT: [6]: HasSideEffects (U)
+# WITHENCODINGS-NEXT: [7]: Encoding Size
+
+# NORMAL: [1] [2] [3] [4] [5] [6] Instructions:
+# NORMAL-NEXT: 1 3 1.00 * movq 368(%rbp), %r10
+# NORMAL-NEXT: 1 2 1.00 leal (%r8,%r8,2), %r9d
+# NORMAL-NEXT: 1 1 0.50 movslq %r9d, %r9
+# NORMAL-NEXT: 1 1 0.50 incl %r8d
+# NORMAL-NEXT: 1 3 1.00 * movq 376(%rbp), %r11
+# NORMAL-NEXT: 1 5 1.00 * vmovups (%r10,%r9,4), %xmm3
+# NORMAL-NEXT: 1 1 0.50 vpslldq $4, %xmm3, %xmm2
+# NORMAL-NEXT: 1 1 0.50 vpslldq $4, %xmm3, %xmm4
+# NORMAL-NEXT: 1 3 1.00 vaddps %xmm2, %xmm3, %xmm6
+# NORMAL-NEXT: 1 1 0.50 vpslldq $12, %xmm3, %xmm5
+# NORMAL-NEXT: 1 3 1.00 vaddps %xmm4, %xmm5, %xmm7
+# NORMAL-NEXT: 1 3 1.00 vaddps %xmm6, %xmm7, %xmm8
+# NORMAL-NEXT: 1 3 1.00 vaddps %xmm8, %xmm0, %xmm9
+# NORMAL-NEXT: 1 1 0.50 vshufps $255, %xmm9, %xmm9, %xmm0
+# NORMAL-NEXT: 1 1 1.00 * vmovups %xmm9, (%r11,%r9,4)
+# NORMAL-NEXT: 1 1 0.50 cmpl %r8d, %esi
+# NORMAL-NEXT: 1 1 0.50 jl -90
+
+# WITHENCODINGS: [1] [2] [3] [4] [5] [6] [7] Encodings: Instructions:
+# WITHENCODINGS-NEXT: 1 3 1.00 * 7 4c 8b 95 70 01 00 00 movq 368(%rbp), %r10
+# WITHENCODINGS-NEXT: 1 2 1.00 4 47 8d 0c 40 leal (%r8,%r8,2), %r9d
+# WITHENCODINGS-NEXT: 1 1 0.50 3 4d 63 c9 movslq %r9d, %r9
+# WITHENCODINGS-NEXT: 1 1 0.50 3 41 ff c0 incl %r8d
+# WITHENCODINGS-NEXT: 1 3 1.00 * 7 4c 8b 9d 78 01 00 00 movq 376(%rbp), %r11
+# WITHENCODINGS-NEXT: 1 5 1.00 * 6 c4 81 78 10 1c 8a vmovups (%r10,%r9,4), %xmm3
+# WITHENCODINGS-NEXT: 1 1 0.50 5 c5 e9 73 fb 04 vpslldq $4, %xmm3, %xmm2
+# WITHENCODINGS-NEXT: 1 1 0.50 5 c5 d9 73 fb 04 vpslldq $4, %xmm3, %xmm4
+# WITHENCODINGS-NEXT: 1 3 1.00 4 c5 e0 58 f2 vaddps %xmm2, %xmm3, %xmm6
+# WITHENCODINGS-NEXT: 1 1 0.50 5 c5 d1 73 fb 0c vpslldq $12, %xmm3, %xmm5
+# WITHENCODINGS-NEXT: 1 3 1.00 4 c5 d0 58 fc vaddps %xmm4, %xmm5, %xmm7
+# WITHENCODINGS-NEXT: 1 3 1.00 4 c5 40 58 c6 vaddps %xmm6, %xmm7, %xmm8
+# WITHENCODINGS-NEXT: 1 3 1.00 5 c4 41 78 58 c8 vaddps %xmm8, %xmm0, %xmm9
+# WITHENCODINGS-NEXT: 1 1 0.50 6 c4 c1 30 c6 c1 ff vshufps $255, %xmm9, %xmm9, %xmm0
+# WITHENCODINGS-NEXT: 1 1 1.00 * 6 c4 01 78 11 0c 8b vmovups %xmm9, (%r11,%r9,4)
+# WITHENCODINGS-NEXT: 1 1 0.50 3 44 39 c6 cmpl %r8d, %esi
+# WITHENCODINGS-NEXT: 1 1 0.50 6 0f 8c 00 00 00 00 jl -90
diff --git a/llvm/tools/llvm-mca/Views/InstructionInfoView.cpp b/llvm/tools/llvm-mca/Views/InstructionInfoView.cpp
index 1fbffa3..a6f9153 100644
--- a/llvm/tools/llvm-mca/Views/InstructionInfoView.cpp
+++ b/llvm/tools/llvm-mca/Views/InstructionInfoView.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "Views/InstructionInfoView.h"
+#include "llvm/Support/FormattedStream.h"
namespace llvm {
namespace mca {
@@ -26,10 +27,17 @@
TempStream << "\n\nInstruction Info:\n";
TempStream << "[1]: #uOps\n[2]: Latency\n[3]: RThroughput\n"
- << "[4]: MayLoad\n[5]: MayStore\n[6]: HasSideEffects (U)\n\n";
+ << "[4]: MayLoad\n[5]: MayStore\n[6]: HasSideEffects (U)\n";
+ if (PrintEncodings) {
+ TempStream << "[7]: Encoding Size\n";
+ TempStream << "\n[1] [2] [3] [4] [5] [6] [7] "
+ << "Encodings: Instructions:\n";
+ } else {
+ TempStream << "\n[1] [2] [3] [4] [5] [6] Instructions:\n";
+ }
- TempStream << "[1] [2] [3] [4] [5] [6] Instructions:\n";
- for (const MCInst &Inst : Source) {
+ for (unsigned I = 0, E = Source.size(); I < E; ++I) {
+ const MCInst &Inst = Source[I];
const MCInstrDesc &MCDesc = MCII.get(Inst.getOpcode());
// Obtain the scheduling class information from the instruction.
@@ -72,7 +80,20 @@
}
TempStream << (MCDesc.mayLoad() ? " * " : " ");
TempStream << (MCDesc.mayStore() ? " * " : " ");
- TempStream << (MCDesc.hasUnmodeledSideEffects() ? " U " : " ");
+ TempStream << (MCDesc.hasUnmodeledSideEffects() ? " U " : " ");
+
+ if (PrintEncodings) {
+ StringRef Encoding(CE.getEncoding(I));
+ unsigned EncodingSize = Encoding.size();
+ TempStream << " " << EncodingSize
+ << (EncodingSize < 10 ? " " : " ");
+ TempStream.flush();
+ formatted_raw_ostream FOS(TempStream);
+ for (unsigned i = 0, e = Encoding.size(); i != e; ++i)
+ FOS << format("%02x ", (uint8_t)Encoding[i]);
+ FOS.PadToColumn(30);
+ FOS.flush();
+ }
MCIP.printInst(&Inst, InstrStream, "", STI);
InstrStream.flush();
@@ -80,7 +101,7 @@
// Consume any tabs or spaces at the beginning of the string.
StringRef Str(Instruction);
Str = Str.ltrim();
- TempStream << " " << Str << '\n';
+ TempStream << Str << '\n';
Instruction = "";
}
diff --git a/llvm/tools/llvm-mca/Views/InstructionInfoView.h b/llvm/tools/llvm-mca/Views/InstructionInfoView.h
index 640d873..0e94830 100644
--- a/llvm/tools/llvm-mca/Views/InstructionInfoView.h
+++ b/llvm/tools/llvm-mca/Views/InstructionInfoView.h
@@ -40,6 +40,7 @@
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MCA/CodeEmitter.h"
#include "llvm/Support/raw_ostream.h"
#define DEBUG_TYPE "llvm-mca"
@@ -51,14 +52,18 @@
class InstructionInfoView : public View {
const llvm::MCSubtargetInfo &STI;
const llvm::MCInstrInfo &MCII;
+ CodeEmitter &CE;
+ bool PrintEncodings;
llvm::ArrayRef<llvm::MCInst> Source;
llvm::MCInstPrinter &MCIP;
public:
- InstructionInfoView(const llvm::MCSubtargetInfo &sti,
- const llvm::MCInstrInfo &mcii,
- llvm::ArrayRef<llvm::MCInst> S, llvm::MCInstPrinter &IP)
- : STI(sti), MCII(mcii), Source(S), MCIP(IP) {}
+ InstructionInfoView(const llvm::MCSubtargetInfo &ST,
+ const llvm::MCInstrInfo &II, CodeEmitter &C,
+ bool ShouldPrintEncodings, llvm::ArrayRef<llvm::MCInst> S,
+ llvm::MCInstPrinter &IP)
+ : STI(ST), MCII(II), CE(C), PrintEncodings(ShouldPrintEncodings),
+ Source(S), MCIP(IP) {}
void printView(llvm::raw_ostream &OS) const override;
};
diff --git a/llvm/tools/llvm-mca/llvm-mca.cpp b/llvm/tools/llvm-mca/llvm-mca.cpp
index 63a748c..1bcf850 100644
--- a/llvm/tools/llvm-mca/llvm-mca.cpp
+++ b/llvm/tools/llvm-mca/llvm-mca.cpp
@@ -32,12 +32,15 @@
#include "Views/SchedulerStatistics.h"
#include "Views/SummaryView.h"
#include "Views/TimelineView.h"
+#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmInfo.h"
-#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCTargetOptionsCommandFlags.inc"
+#include "llvm/MCA/CodeEmitter.h"
#include "llvm/MCA/Context.h"
#include "llvm/MCA/InstrBuilder.h"
#include "llvm/MCA/Pipeline.h"
@@ -200,6 +203,11 @@
cl::desc("Enable bottleneck analysis (disabled by default)"),
cl::cat(ViewOptions), cl::init(false));
+static cl::opt<bool> ShowEncoding(
+ "show-encoding",
+ cl::desc("Print encoding information in the instruction info view"),
+ cl::cat(ViewOptions), cl::init(false));
+
namespace {
const Target *getTarget(const char *ProgName) {
@@ -424,6 +432,12 @@
// Number each region in the sequence.
unsigned RegionIdx = 0;
+ std::unique_ptr<MCCodeEmitter> MCE(
+ TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
+
+ std::unique_ptr<MCAsmBackend> MAB(TheTarget->createMCAsmBackend(
+ *STI, *MRI, InitMCTargetOptionsFromFlags()));
+
for (const std::unique_ptr<mca::CodeRegion> &Region : Regions) {
// Skip empty code regions.
if (Region->empty())
@@ -441,6 +455,7 @@
// Lower the MCInst sequence into an mca::Instruction sequence.
ArrayRef<MCInst> Insts = Region->getInstructions();
+ mca::CodeEmitter CE(*STI, *MAB, *MCE, Insts);
std::vector<std::unique_ptr<mca::Instruction>> LoweredSequence;
for (const MCInst &MCI : Insts) {
Expected<std::unique_ptr<mca::Instruction>> Inst =
@@ -478,7 +493,7 @@
// Create the views for this pipeline, execute, and emit a report.
if (PrintInstructionInfoView) {
Printer.addView(llvm::make_unique<mca::InstructionInfoView>(
- *STI, *MCII, Insts, *IP));
+ *STI, *MCII, CE, ShowEncoding, Insts, *IP));
}
Printer.addView(
llvm::make_unique<mca::ResourcePressureView>(*STI, *IP, Insts));
@@ -504,8 +519,8 @@
}
if (PrintInstructionInfoView)
- Printer.addView(
- llvm::make_unique<mca::InstructionInfoView>(*STI, *MCII, Insts, *IP));
+ Printer.addView(llvm::make_unique<mca::InstructionInfoView>(
+ *STI, *MCII, CE, ShowEncoding, Insts, *IP));
if (PrintDispatchStats)
Printer.addView(llvm::make_unique<mca::DispatchStatistics>());