test/demangler-tests.js

// Copyright (c) 2018, Compiler Explorer Authors
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import {CppDemangler, Win32Demangler} from '../lib/demangler';
import {PrefixTree} from '../lib/demangler/prefix-tree';
import * as exec from '../lib/exec';
import {SymbolStore} from '../lib/symbol-store';
import * as utils from '../lib/utils';

import {chai, fs, path, resolvePathFromTestRoot} from './utils';

const cppfiltpath = 'c++filt';

class DummyCompiler {
    exec(command, args, options) {
        return exec.execute(command, args, options);
    }
}

const catchCppfiltNonexistence = err => {
    if (!err.message.startsWith('spawn c++filt')) {
        throw err;
    }
};

describe('Basic demangling', function () {
    it('One line of asm', function () {
        const result = {
            asm: [{text: 'Hello, World!'}],
        };

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];

        return Promise.all([
            demangler.process(result).then(output => {
                output.asm[0].text.should.equal('Hello, World!');
            }),
        ]);
    });

    it('One label and some asm', function () {
        const result = {asm: [{text: '_Z6squarei:'}, {text: '  ret'}]};

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];

        return Promise.all([
            demangler
                .process(result)
                .then(output => {
                    output.asm[0].text.should.equal('square(int):');
                    output.asm[1].text.should.equal('  ret');
                })
                .catch(catchCppfiltNonexistence),
        ]);
    });

    it('One label and use of a label', function () {
        const result = {asm: [{text: '_Z6squarei:'}, {text: '  mov eax, $_Z6squarei'}]};

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];

        return Promise.all([
            demangler
                .process(result)
                .then(output => {
                    output.asm[0].text.should.equal('square(int):');
                    output.asm[1].text.should.equal('  mov eax, $square(int)');
                })
                .catch(catchCppfiltNonexistence),
        ]);
    });

    it('Two destructors', function () {
        const result = {
            asm: [
                {text: '_ZN6NormalD0Ev:'},
                {text: '  callq _ZdlPv'},
                {text: '_Z7caller1v:'},
                {text: '  rep ret'},
                {text: '_Z7caller2P6Normal:'},
                {text: '  cmp rax, OFFSET FLAT:_ZN6NormalD0Ev'},
                {text: '  jmp _ZdlPvm'},
                {text: '_ZN6NormalD2Ev:'},
                {text: '  rep ret'},
            ],
        };

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];

        return demangler
            .process(result)
            .then(output => {
                output.asm[0].text.should.equal('Normal::~Normal() [deleting destructor]:');
                output.asm[1].text.should.equal('  callq operator delete(void*)');
                output.asm[6].text.should.equal('  jmp operator delete(void*, unsigned long)');
            })
            .catch(catchCppfiltNonexistence);
    });

    it('Should ignore comments (CL)', function () {
        const result = {asm: [{text: '        call     ??3@YAXPEAX_K@Z                ; operator delete'}]};

        const demangler = new Win32Demangler(cppfiltpath, new DummyCompiler());
        demangler.result = result;
        demangler.symbolstore = new SymbolStore();
        demangler.collectLabels();

        const output = demangler.win32RawSymbols;
        output.should.deep.equal(['??3@YAXPEAX_K@Z']);
    });

    it('Should ignore comments (CPP)', function () {
        const result = {asm: [{text: '        call     hello                ; operator delete'}]};

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];
        demangler.result = result;
        demangler.symbolstore = new SymbolStore();
        demangler.collectLabels();

        const output = demangler.othersymbols.listSymbols();
        output.should.deep.equal(['hello']);
    });

    it('Should also support ARM branch instructions', () => {
        const result = {asm: [{text: '   bl _ZN3FooC1Ev'}]};

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];
        demangler.result = result;
        demangler.symbolstore = new SymbolStore();
        demangler.collectLabels();

        const output = demangler.othersymbols.listSymbols();
        output.should.deep.equal(['_ZN3FooC1Ev']);
    });

    it('Should NOT handle undecorated labels', () => {
        const result = {asm: [{text: '$LN3@caller2:'}]};

        const demangler = new Win32Demangler(cppfiltpath, new DummyCompiler());
        demangler.result = result;
        demangler.symbolstore = new SymbolStore();
        demangler.collectLabels();

        const output = demangler.win32RawSymbols;
        output.should.deep.equal([]);
    });

    it('Should ignore comments after jmps', function () {
        const result = {asm: [{text: '  jmp _Z1fP6mytype # TAILCALL'}]};

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];
        demangler.result = result;
        demangler.symbolstore = new SymbolStore();
        demangler.collectLabels();

        const output = demangler.othersymbols.listSymbols();
        output.should.deep.equal(['_Z1fP6mytype']);
    });

    it('Should still work with normal jmps', function () {
        const result = {asm: [{text: '  jmp _Z1fP6mytype'}]};

        const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
        demangler.demanglerArguments = ['-n'];
        demangler.result = result;
        demangler.symbolstore = new SymbolStore();
        demangler.collectLabels();

        const output = demangler.othersymbols.listSymbols();
        output.should.deep.equal(['_Z1fP6mytype']);
    });
});

async function readResultFile(filename) {
    const data = await fs.readFile(filename);
    const asm = utils.splitLines(data.toString()).map(line => {
        return {text: line};
    });

    return {asm};
}

async function DoDemangleTest(filename) {
    const resultIn = await readResultFile(filename);
    const resultOut = await readResultFile(filename + '.demangle');

    const demangler = new CppDemangler(cppfiltpath, new DummyCompiler());
    demangler.demanglerArguments = ['-n'];
    return demangler.process(resultIn).should.eventually.deep.equal(resultOut);
}

describe('File demangling', () => {
    if (process.platform !== 'linux') {
        it('Should be skipped', done => {
            done();
        });

        return;
    }

    const testcasespath = resolvePathFromTestRoot('demangle-cases');

    /*
     * NB: this readdir must *NOT* be async
     *
     * Mocha calls the function passed to `describe` synchronously
     * and expects the test suite to be fully configured upon return.
     *
     * If you pass an async function to describe and setup test cases
     * after an await there is no guarantee they will be found, and
     * if they are they will not end up in the expected suite.
     */
    const files = fs.readdirSync(testcasespath);

    for (const filename of files) {
        if (filename.endsWith('.asm')) {
            it(filename, async () => {
                await DoDemangleTest(path.join(testcasespath, filename));
            });
        }
    }
});

describe('Demangler prefix tree', () => {
    const replacements = new PrefixTree();
    replacements.add('a', 'short_a');
    replacements.add('aa', 'long_a');
    replacements.add('aa_shouldnotmatch', 'ERROR');
    it('should replace a short match', () => {
        replacements.replaceAll('a').should.eq('short_a');
    });
    it('should replace using the longest match', () => {
        replacements.replaceAll('aa').should.eq('long_a');
    });
    it('should replace using both', () => {
        replacements.replaceAll('aaa').should.eq('long_ashort_a');
    });
    it('should replace using both', () => {
        replacements.replaceAll('a aa a aa').should.eq('short_a long_a short_a long_a');
    });
    it('should work with empty replacements', () => {
        new PrefixTree().replaceAll('Testing 123').should.eq('Testing 123');
    });
    it('should leave unmatching text alone', () => {
        replacements
            .replaceAll('Some text with none of the first letter of the ordered letter list')
            .should.eq('Some text with none of the first letter of the ordered letter list');
    });
    it('should handle a mixture', () => {
        replacements.replaceAll('Everyone loves an aardvark').should.eq('Everyone loves short_an long_ardvshort_ark');
    });
    it('should find exact matches', () => {
        replacements.findExact('a').should.eq('short_a');
        replacements.findExact('aa').should.eq('long_a');
        replacements.findExact('aa_shouldnotmatch').should.eq('ERROR');
    });
    it('should find not find mismatches', () => {
        chai.expect(replacements.findExact('aaa')).to.be.null;
        chai.expect(replacements.findExact(' aa')).to.be.null;
        chai.expect(replacements.findExact(' a')).to.be.null;
        chai.expect(replacements.findExact('Oh noes')).to.be.null;
        chai.expect(replacements.findExact('')).to.be.null;
    });
});