perf(ivy): reuse prior analysis work during incremental builds (#34288)

Previously, the compiler performed an incremental build by analyzing and
resolving all classes in the program (even unchanged ones) and then using
the dependency graph information to determine which .js files were stale and
needed to be re-emitted. This algorithm produced "correct" rebuilds, but the
cost of re-analyzing the entire program turned out to be higher than
anticipated, especially for component-heavy compilations.

To achieve performant rebuilds, it is necessary to reuse previous analysis
results if possible. Doing this safely requires knowing when prior work is
viable and when it is stale and needs to be re-done.

The new algorithm implemented by this commit is such:

1) Each incremental build starts with knowledge of the last known good
   dependency graph and analysis results from the last successful build,
   plus of course information about the set of files changed.

2) The previous dependency graph's information is used to determine the
   set of source files which have "logically" changed. A source file is
   considered logically changed if it or any of its dependencies have
   physically changed (on disk) since the last successful compilation. Any
   logically unchanged dependencies have their dependency information copied
   over to the new dependency graph.

3) During the `TraitCompiler`'s loop to consider all source files in the
   program, if a source file is logically unchanged then its previous
   analyses are "adopted" (and their 'register' steps are run). If the file
   is logically changed, then it is re-analyzed as usual.

4) Then, incremental build proceeds as before, with the new dependency graph
   being used to determine the set of files which require re-emitting.

This analysis reuse avoids template parsing operations in many circumstances
and significantly reduces the time it takes ngtsc to rebuild a large
application.

Future work will increase performance even more, by tackling a variety of
other opportunities to reuse or avoid work.

PR Close #34288
This commit is contained in:
Alex Rickabaugh
2019-12-05 16:03:17 -08:00
committed by Kara Erickson
parent 50cdc0ac1b
commit 74edde0a94
39 changed files with 580 additions and 222 deletions

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@ -159,7 +159,7 @@ describe('Evaluator', () => {
});
});
it('should support referene to a declared module type', () => {
it('should support reference to a declared module type', () => {
const declared = program.getSourceFile('declared.ts') !;
const aDecl = findVar(declared, 'a') !;
expect(evaluator.evaluateNode(aDecl.type !)).toEqual({

View File

@ -32,13 +32,14 @@ runInEachFileSystem(() => {
function expectToHaveWritten(files: string[]): void {
const set = env.getFilesWrittenSinceLastFlush();
const expectedSet = new Set<string>();
for (const file of files) {
expect(set).toContain(file);
expect(set).toContain(file.replace(/\.js$/, '.d.ts'));
expectedSet.add(file);
expectedSet.add(file.replace(/\.js$/, '.d.ts'));
}
// Validate that 2x the size of `files` have been written (one .d.ts, one .js) and no more.
expect(set.size).toBe(2 * files.length);
expect(set).toEqual(expectedSet);
// Reset for the next compilation.
env.flushWrittenFileTracking();
@ -479,7 +480,7 @@ runInEachFileSystem(() => {
'/other.js',
// Because a.html changed
'/a.js',
'/a.js', '/module.js',
// b.js and module.js should not be re-emitted, because specifically when tracking
// resource dependencies, the compiler knows that a change to a resource file only affects

View File

@ -160,7 +160,7 @@ runInEachFileSystem(() => {
expect(written).toContain('/bar_directive.js');
expect(written).toContain('/bar_component.js');
expect(written).toContain('/bar_module.js');
expect(written).not.toContain('/foo_component.js');
expect(written).toContain('/foo_component.js');
expect(written).not.toContain('/foo_pipe.js');
expect(written).not.toContain('/foo_module.js');
});
@ -251,7 +251,7 @@ runInEachFileSystem(() => {
expect(written).toContain('/foo_module.js');
});
it('should rebuild only a Component (but with the correct CompilationScope) if its template has changed',
it('should rebuild only a Component (but with the correct CompilationScope) and its module if its template has changed',
() => {
setupFooBarProgram(env);
@ -262,7 +262,9 @@ runInEachFileSystem(() => {
const written = env.getFilesWrittenSinceLastFlush();
expect(written).not.toContain('/bar_directive.js');
expect(written).toContain('/bar_component.js');
expect(written).not.toContain('/bar_module.js');
// /bar_module.js should also be re-emitted, because remote scoping of BarComponent might
// have been affected.
expect(written).toContain('/bar_module.js');
expect(written).not.toContain('/foo_component.js');
expect(written).not.toContain('/foo_pipe.js');
expect(written).not.toContain('/foo_module.js');