Commit 742fa941 authored by Pavel Kosov's avatar Pavel Kosov
Browse files

[llvm-exegesis] Skip codegen of known-invalid snippets 

On some targets, not all types of instruction operands are currently
handled. Instead of stopping the whole llvm-exegesis run because of any
instruction opcode that is not fully supported, write a per-opcode error
message and proceed to other opcodes. This improves the reliability of
--opcode-index=-1 sweep on partially supported targets.

Depends on: D146302, D146303

~~

Huawei RRI, OS Lab

Reviewed By: courbet

Differential Revision: https://reviews.llvm.org/D146304
parent ce0d16f5

llvm/test/tools/llvm-exegesis/AArch64/all-opcodes.test

0 → 100644
+10 −0
Original line number Diff line number Diff line 
# Test that we can just use --opcode-index=-1 to generate snippets for

# all supported opcodes and gracefully handle unsupported ones.



# RUN: llvm-exegesis --mtriple=aarch64-linux-gnu --mcpu=cortex-a55 --benchmark-phase=prepare-and-assemble-snippet \

# RUN:               --mode=latency --opcode-index=-1 | FileCheck %s

# RUN: llvm-exegesis --mtriple=aarch64-linux-gnu --mcpu=cortex-a55 --benchmark-phase=prepare-and-assemble-snippet \

# RUN:               --mode=uops --opcode-index=-1 | FileCheck %s



# 100 means "quite a lot"

# CHECK-COUNT-100: assembled_snippet: {{.*}}

llvm/tools/llvm-exegesis/lib/SnippetGenerator.cpp

+23 −3
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include "llvm/ADT/StringExtras.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/ADT/Twine.h"

#include "llvm/Support/Error.h"

#include "llvm/Support/FileSystem.h"

#include "llvm/Support/FormatVariadic.h"

#include "llvm/Support/Program.h"
@@ -77,9 +78,12 @@ Error SnippetGenerator::generateConfigurations( 
        BC.Info = CT.Info;

        BC.Key.Instructions.reserve(CT.Instructions.size());

        for (InstructionTemplate &IT : CT.Instructions) {

          if (auto error = randomizeUnsetVariables(State, ForbiddenRegs, IT))

            return error;

          BC.Key.Instructions.push_back(IT.build());

          if (auto Error = randomizeUnsetVariables(State, ForbiddenRegs, IT))

            return Error;

          MCInst Inst = IT.build();

          if (auto Error = validateGeneratedInstruction(State, Inst))

            return Error;

          BC.Key.Instructions.push_back(Inst);

        }

        if (CT.ScratchSpacePointerInReg)

          BC.LiveIns.push_back(CT.ScratchSpacePointerInReg);
@@ -282,5 +286,21 @@ Error randomizeUnsetVariables(const LLVMState &State, 
  return Error::success();

}



Error validateGeneratedInstruction(const LLVMState &State, const MCInst &Inst) {

  for (const auto &Operand : Inst) {

    if (!Operand.isValid()) {

      // Mention the particular opcode - it is not necessarily the "main"

      // opcode being benchmarked by this snippet. For example, serial snippet

      // generator uses one more opcode when in SERIAL_VIA_NON_MEMORY_INSTR

      // execution mode.

      const auto OpcodeName = State.getInstrInfo().getName(Inst.getOpcode());

      return make_error<Failure>("Not all operands were initialized by the "

                                 "snippet generator for " +

                                 OpcodeName + " opcode.");

    }

  }

  return Error::success();

}



} // namespace exegesis

} // namespace llvm

llvm/tools/llvm-exegesis/lib/SnippetGenerator.h

+3 −0
Original line number Diff line number Diff line
@@ -107,6 +107,9 @@ Error randomizeUnsetVariables(const LLVMState &State, 
                              const BitVector &ForbiddenRegs,

                              InstructionTemplate &IT);



// Sanity check generated instruction.

Error validateGeneratedInstruction(const LLVMState &State, const MCInst &Inst);



} // namespace exegesis

} // namespace llvm