Merge #57030 #57039

57030: execgen: permit customization of template path r=jordanlewis a=jordanlewis

Closes #56982

This commit adds a new argument to execgen, -template, which allows
customization of the file path of the input template for a given output
file.

Here's an example of how to run execgen with cutomized paths:

```
execgen -template path/to/template_tmpl.go path/to/eventual/generated/code.eg.go > path/to/wherever/you/want/to/write/the/file.eg.o
```

The second argument is important because it is used as an argument to
`goimports`, which needs to the actual, eventual path that the generated
code will live at. Note that it doesn't actually need to *write* to that
filepath - just needs to know what the name will be, eventually.

Release note: None

57039: bazel: add freebsd support r=irfansharif a=irfansharif

Fixes #56013. We're picking up bazel-contrib/rules_foreign_cc/pull/387
(included in our new fork at [cockroachdb/rules_foreign_cc](https://github.com/cockroachdb/rules_foreign_cc/)). We've also
picked up Oliver's PR adding autoconf support
(bazel-contrib/rules_foreign_cc/pull/432); we were pointing to Oliver's own
fork previously to pick up those changes.

Release note: None

---

@knz, wanna try this branch out and see if it works? If not, I should probably spin up a freebsd AMI next once someone shows me how.

Co-authored-by: Jordan Lewis <[email protected]>
Co-authored-by: irfan sharif <[email protected]>

WORKSPACE

@@ -66,14 +66,17 @@ load("//c-deps:REPOSITORIES.bzl", "c_deps")
 c_deps()
 
 
-# Load the bazel utility that lets us build C/C++ projects using cmake/make/etc.
+# Load the bazel utility that lets us build C/C++ projects using
+# cmake/make/etc. We point our fork which adds autoconf support
+# (https://github.com/bazelbuild/rules_foreign_cc/pull/432) and BSD support
+# (https://github.com/bazelbuild/rules_foreign_cc/pull/387).
 #
-# TODO(irfansharif): Point to an upstream SHA once it picks up Oliver's changes
-# that add autoconf support.
+# TODO(irfansharif): Point to an upstream SHA once maintainers pick up the
+# aforementioned PRs.
 git_repository(
    name = "rules_foreign_cc",
-   commit = "605c77171f20840464301d7d01d6cd9e3a982888",
-   remote = "https://github.com/otan-cockroach/rules_foreign_cc",
+   commit = "8fdca4480f3fa9c084f4a73749a46fa17996beb1",
+   remote = "https://github.com/cockroachdb/rules_foreign_cc",
 )
 load("@rules_foreign_cc//:workspace_definitions.bzl", "rules_foreign_cc_dependencies")
 rules_foreign_cc_dependencies()

pkg/sql/colexec/execgen/cmd/execgen/main.go

@@ -26,10 +26,6 @@ import (
 	"github.com/cockroachdb/gostdlib/x/tools/imports"
 )
 
-var (
-	errInvalidArgCount = errors.New("invalid number of arguments")
-)
-
 func main() {
 	gen := execgenTool{stdErr: os.Stderr}
 	if !gen.run(os.Args[1:]...) {
@@ -71,45 +67,45 @@ func registerGenerator(g generator, outputFile, inputFile string) {
 func (g *execgenTool) run(args ...string) bool {
 	// Parse command line.
 	var printDeps bool
+	var template string
 	g.cmdLine = flag.NewFlagSet("execgen", flag.ContinueOnError)
 	g.cmdLine.SetOutput(g.stdErr)
 	g.cmdLine.Usage = g.usage
 	g.cmdLine.BoolVar(&g.fmtSources, "fmt", true, "format and imports-process generated code")
 	g.cmdLine.BoolVar(&g.verbose, "verbose", false, "print out debug information to stderr")
 	g.cmdLine.BoolVar(&printDeps, "M", false, "print the dependency list")
+	g.cmdLine.StringVar(&template, "template", "", "path")
 	err := g.cmdLine.Parse(args)
 	if err != nil {
 		return false
 	}
 
 	// Get remaining args after any flags have been parsed.
 	args = g.cmdLine.Args()
-	if len(args) < 1 {
+	if len(args) != 1 {
 		g.cmdLine.Usage()
-		g.reportError(errInvalidArgCount)
+		g.reportError(errors.New("invalid number of arguments"))
 		return false
 	}
 
-	for _, out := range args {
-		_, file := filepath.Split(out)
-		e := generators[file]
-		if e.fn == nil {
-			g.reportError(errors.Errorf("unrecognized filename: %s", file))
+	outPath := args[0]
+
+	_, file := filepath.Split(outPath)
+	e := generators[file]
+	if e.fn == nil {
+		g.reportError(errors.Errorf("unrecognized filename: %s", file))
+		return false
+	}
+	if template != "" {
+		if e.inputFile == "" {
+			g.reportError(errors.Errorf("file %s expected no input template, found %s", file, template))
 			return false
 		}
-		if printDeps {
-			if e.inputFile == "" {
-				// This output file has no template dependency (its template
-				// is embedded entirely in execgenTool). Skip it.
-				continue
-			}
-			fmt.Printf("%s: %s\n", out, e.inputFile)
-		} else {
-			if err := g.generate(out, e); err != nil {
-				g.reportError(err)
-				return false
-			}
-		}
+		e.inputFile = template
+	}
+	if err := g.generate(outPath, e); err != nil {
+		g.reportError(err)
+		return false
 	}
 	return true
 }