add benchmarks to compare protocompile perf and memory usage against other compilers

.github/workflows/ci.yaml

@@ -33,10 +33,14 @@ jobs:
           restore-keys: ${{ runner.os }}-protocompile-ci-
       - name: Test
         run: make test
+      - name: Benchmarks
+        # no need to run benchmarks for every Go version
+        if: matrix.go-version == '1.19.x'
+        run: make benchmarks
       - name: Lint
         # Often, lint & gofmt guidelines depend on the Go version. To prevent
         # conflicting guidance, run only on the most recent supported version.
         # For the same reason, only check generated code on the most recent
         # supported version.
         if: matrix.go-version == '1.19.x'
-        run: make checkgenerate && make lint
+        run: make checkgenerate lint

.golangci.yml

@@ -85,3 +85,8 @@ issues:
     # Don't ban use of fmt.Errorf to create new errors, but the remaining
     # checks from err113 are useful.
     - "err113: do not define dynamic errors.*"
+  exclude-rules:
+    # Benchmarks can't be run in parallel
+    - path: benchmark_test\.go
+      linters:
+        - paralleltest

Makefile

@@ -15,6 +15,7 @@ TOOLS_MOD_DIR := ./internal/tools
 UNAME_OS := $(shell uname -s)
 UNAME_ARCH := $(shell uname -m)
 
+# NB: this must be kept in sync with constant in internal/benchmarks.
 PROTOC_VERSION ?= 21.7
 PROTOC_DIR := $(abspath ./internal/testdata/protoc/$(PROTOC_VERSION))
 PROTOC := $(PROTOC_DIR)/bin/protoc
@@ -50,6 +51,10 @@ clean: ## Delete intermediate build artifacts
 test: build ## Run unit tests
 	$(GO) test -vet=off -race -cover ./...
 
+.PHONY: benchmarks
+benchmarks: build ## Run benchmarks
+	cd internal/benchmarks && $(GO) test -bench=. -benchmem -v ./...
+
 .PHONY: build
 build: generate ## Build all packages
 	$(GO) build ./...
@@ -60,12 +65,14 @@ install: ## Install all binaries
 
 .PHONY: lint
 lint: $(BIN)/golangci-lint ## Lint Go
-	$(GO) vet ./...
+	$(GO) vet ./... ./internal/benchmarks/...
 	$(BIN)/golangci-lint run
+	cd internal/benchmarks && $(BIN)/golangci-lint run
 
 .PHONY: lintfix
 lintfix: $(BIN)/golangci-lint ## Automatically fix some lint errors
 	$(BIN)/golangci-lint run --fix
+	cd internal/benchmarks && $(BIN)/golangci-lint run --fix
 
 .PHONY: generate
 generate: $(BIN)/license-header $(BIN)/goyacc test-descriptors ## Regenerate code and licenses

compiler.go

@@ -80,6 +80,13 @@ type Compiler struct {
 	// concludes. Similarly, if they already have source code info but this flag
 	// is false, existing info will be left in place.
 	SourceInfoMode SourceInfoMode
+
+	// If true, ASTs are retained in compilation results for which an AST was
+	// constructed. So any linker.Result value in the resulting compiled files
+	// will have an AST, in addition to descriptors. If left false, the AST
+	// will be removed as soon as it's no longer needed. This can help reduce
+	// total memory usage for operations involving a large number of files.
+	RetainASTs bool
 }
 
 // SourceInfoMode indicates how source code info is generated by a Compiler.
@@ -518,6 +525,10 @@ func (t *task) link(parseRes parser.Result, deps linker.Files) (linker.File, err
 		}
 		file.PopulateSourceCodeInfo()
 	}
+
+	if !t.e.c.RetainASTs {
+		file.RemoveAST()
+	}
 	return file, nil
 }
 

go.work

@@ -0,0 +1,7 @@
+go 1.19
+
+use (
+	.
+	./internal/benchmarks
+	./internal/tools
+)