Allow implementing different WIT worlds in wasip2 target

As mentioned in [this comment](#4843 (comment)), we are also interested in Wasm components with custom worlds (for [Grafbase extensions](https://grafbase.com/docs/gateway/extensions)).

I have succesfully compiled and used examples based on the changes in this branch. They are mostly from @daedric's patch in the issue.

So this PR is meant as a starting point for discussions, a working branch for anyone else looking at trying this, and to discuss how best to test it (I've made attempts, but they added up to a lot of code, and I wasn't too happy with them).

I understand it's work to review and merge something like this, and even more to provide guidance on a proper test setup, so while feedback would be much appreciated, I understand if it's not a priority.

fixes #4843

Author: tomhoule

builder/build.go

@@ -914,6 +914,11 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 			}
 
 			// Run wasm-tools for component-model binaries
+			wasiPackage := strings.ReplaceAll(config.Target.WASIPackage, "{root}", goenv.Get("TINYGOROOT"))
+			if config.Options.WASIPackage != "" {
+				wasiPackage = config.Options.WASIPackage
+			}
+
 			witPackage := strings.ReplaceAll(config.Target.WITPackage, "{root}", goenv.Get("TINYGOROOT"))
 			if config.Options.WITPackage != "" {
 				witPackage = config.Options.WITPackage
@@ -922,7 +927,37 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 			if config.Options.WITWorld != "" {
 				witWorld = config.Options.WITWorld
 			}
+
 			if witPackage != "" && witWorld != "" {
+				if wasiPackage != "" {
+
+					fmt.Println("Embedding WASI component. Wasi package: ", wasiPackage)
+
+					// wasm-tools component embed -w wasi:cli/command
+					// 		$$(tinygo env TINYGOROOT)/lib/wasi-cli/wit/ main.wasm -o embedded.wasm
+					componentEmbedInputFile := result.Binary
+					result.Binary = result.Executable + ".wasm-component-embed-1"
+					args := []string{
+						"component",
+						"embed",
+						wasiPackage,
+						componentEmbedInputFile,
+						"-o", result.Binary,
+					}
+
+					wasmtools := goenv.Get("WASMTOOLS")
+					if config.Options.PrintCommands != nil {
+						config.Options.PrintCommands(wasmtools, args...)
+					}
+					cmd := exec.Command(wasmtools, args...)
+					cmd.Stdout = os.Stdout
+					cmd.Stderr = os.Stderr
+
+					err := cmd.Run()
+					if err != nil {
+						return fmt.Errorf("`wasm-tools component embed` failed: %w", err)
+					}
+				}
 
 				// wasm-tools component embed -w wasi:cli/command
 				// 		$$(tinygo env TINYGOROOT)/lib/wasi-cli/wit/ main.wasm -o embedded.wasm

compileopts/options.go

@@ -56,6 +56,7 @@ type Options struct {
 	Monitor         bool
 	BaudRate        int
 	Timeout         time.Duration
+	WASIPackage     string // pass trough to wasm-tools component first embed invocation
 	WITPackage      string // pass through to wasm-tools component embed invocation
 	WITWorld        string // pass through to wasm-tools component embed -w option
 	ExtLDFlags      []string

compileopts/target.go

@@ -65,6 +65,7 @@ type TargetSpec struct {
 	JLinkDevice      string   `json:"jlink-device,omitempty"`
 	CodeModel        string   `json:"code-model,omitempty"`
 	RelocationModel  string   `json:"relocation-model,omitempty"`
+	WASIPackage      string   `json:"wasi-package,omitempty"`
 	WITPackage       string   `json:"wit-package,omitempty"`
 	WITWorld         string   `json:"wit-world,omitempty"`
 }

main.go

@@ -1285,19 +1285,19 @@ microcontrollers, it is common to use the .elf file extension to indicate a
 linked ELF file is generated. For Linux, it is common to build binaries with no
 extension at all.`
 
-	usageRun = `Run the program, either directly on the host or in an emulated environment 
+	usageRun = `Run the program, either directly on the host or in an emulated environment
 (depending on -target).`
 
 	usageFlash = `Flash the program to a microcontroller. Some common flags are described below.
 
-	-target={name}: 
+	-target={name}:
 			Specifies the type of microcontroller that is used. The name of the
 			microcontroller is given on the individual pages for each board type
 			listed under Microcontrollers
 			(https://tinygo.org/docs/reference/microcontrollers/).
 			Examples: "arduino-nano", "d1mini", "xiao".
 
-	-monitor: 
+	-monitor:
 			Start the serial monitor (see below) immediately after
 			flashing. However, some microcontrollers need a split second
 			or two to configure the serial port after flashing, and
@@ -1347,7 +1347,7 @@ instead of the expected \n (also known as ^J, NL, or LF) to indicate
 end-of-line. You may be able to get around this problem by hitting Control-J in
 tinygo monitor to transmit the \n end-of-line character.`
 
-	usageGdb = `Build the program, optionally flash it to a microcontroller if it is a remote 
+	usageGdb = `Build the program, optionally flash it to a microcontroller if it is a remote
 target, and drop into a GDB shell. From there you can set breakpoints, start the
 program with "run" or "continue" ("run" for a local program, continue for
 on-chip debugging), single-step, show a backtrace, break and resume the program
@@ -1631,8 +1631,9 @@ func main() {
 		flag.StringVar(&outpath, "o", "", "output filename")
 	}
 
-	var witPackage, witWorld string
+	var witPackage, witWorld, wasiPackage string
 	if command == "help" || command == "build" || command == "test" || command == "run" {
+		flag.StringVar(&wasiPackage, "wasi-package", "", "wasi package for wasm component embedding")
 		flag.StringVar(&witPackage, "wit-package", "", "wit package for wasm component embedding")
 		flag.StringVar(&witWorld, "wit-world", "", "wit world for wasm component embedding")
 	}
@@ -1720,6 +1721,7 @@ func main() {
 		Monitor:         *monitor,
 		BaudRate:        *baudrate,
 		Timeout:         *timeout,
+		WASIPackage:     wasiPackage,
 		WITPackage:      witPackage,
 		WITWorld:        witWorld,
 	}

targets/wasip2.json

@@ -28,6 +28,7 @@
 		"src/runtime/asm_tinygowasm.S"
 	],
 	"emulator": "wasmtime run --wasm component-model -Sinherit-network -Sallow-ip-name-lookup --dir={tmpDir}::/tmp {}",
+     "wasi-package": "{root}/lib/wasi-cli/wit/",
 	"wit-package": "{root}/lib/wasi-cli/wit/",
 	"wit-world": "wasi:cli/command"
 }