Class LLVMMcaTool

lib/tooling/llvm-mca-tool.ts:33–131

import {BaseTool} from './base-tool.js';

export class LLVMMcaTool extends BaseTool {
    static get key() {
        return 'llvm-mca-tool';
    }

    public rewriteAsm(asm: string) {
        return asm
            .replaceAll(/.hword\s/gim, '.short ')
            .replaceAll(/offset flat:/gim, '')
            .replaceAll(/ptr\s%fs/gim, 'PTR fs')
            .replaceAll(/^\s*\.(fnstart|eabi_attribute|fpu).*/gim, '') // https://github.com/compiler-explorer/compiler-explorer/issues/1270
            .replaceAll(/^\s*\.(loc|file).*/gim, ''); // Remove debug directives that can cause "unassigned file number" errors
    }

    writeAsmFile(data: string, destination: string) {
        return fs.writeFile(destination, this.rewriteAsm(data));
    }

    override async runTool(compilationInfo: CompilationInfo, _inputFilepath?: string, args?: string[]) {
        const isets = new InstructionSets();
        let target = isets.getInstructionSetTarget(compilationInfo.compiler.instructionSet);
        const prependArgs: string[] = [];

        // Check if compiler target is overridden with --target=<foo> or -target <foo>.
        let argIsTarget = false;
        for (const arg of compilationInfo.options) {
            if (arg.startsWith('--target=')) target = arg.replace(/^--target=/, '');
            if (argIsTarget) {
                target = arg;
                argIsTarget = false;
            }
            if (arg === '-target') argIsTarget = true;
        }

        if (target) prependArgs.push('-mtriple=' + target);

        let haveCPU = false;
        let haveM32 = false;
        for (const arg of compilationInfo.options) {
            if (arg.startsWith('-march') && (target?.startsWith('x86_64') || target?.startsWith('i386'))) {
                prependArgs.push(arg.replace(/^-march=/, '-mcpu='));
                haveCPU = true;
            }
            if (arg === '-m32') haveM32 = true;
            if (arg.startsWith('-mcpu')) {
                prependArgs.push(arg);
                haveCPU = true;
            }
        }

        if (compilationInfo.filters.binary || compilationInfo.filters.binaryObject) {
            return this.createErrorResponse('<cannot run analysis on binary>');
        }

        // If no other CPU specified, default to mcpu=generic to
        // override llvm-mca's default of -mcpu=native, otherwise MCA's
        // CPU analysis varies according to the machine MCA happens to
        // run on which can change over time.