fix: restore iota blocks, asm --format flag and prose after the syntax pass

cmd/gasm/main.go

@@ -299,7 +299,7 @@ given.
 			rc = 1
 			continue
 		}
-		out := format.Source(path, src)
+		out := format.Source(src)
 		if dirMode || *write {
 			if out != src {
 				if err := os.WriteFile(path, []byte(out), 0o644); err != nil {
@@ -447,7 +447,7 @@ requires -p, the package path, and the installed Go toolchain).
 		return 1
 	}
 
-	img, err := assembleFile(path, targetArch, f)
+	img, err := assembleFile(targetArch, f)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "%s: %v\n", path, err)
 		return 1
@@ -544,7 +544,7 @@ requires -p, the package path, and the installed Go toolchain).
 
 // cmdDiff compares the machine code of two assembly files.
 func cmdDiff(args []string) int {
-	fs := newCommand("diff", "gasm diff <file1.s> <file2.s>", `
+	set := newCommand("diff", "gasm diff <file1.s> <file2.s>", `
 Compare the machine code produced by assembling two files.
 Shows which functions differ and the byte-level differences.
 Useful for verifying that two implementations produce identical code,
@@ -553,13 +553,13 @@ or for tracking encoding changes between Go assembler versions.
 Use --map to compare functions whose names differ between the files,
 e.g. --map wideCopyAVX2=wideCopyAVX512 pairs the two regardless of suffix.
 `)
-	mapSpec := fs.String("map", "", "comma-separated old=new pairs to match functions with different names")
-	fs.Parse(args)
-	if fs.NArg() != 2 {
+	mapSpec := set.String("map", "", "comma-separated old=new pairs to match functions with different names")
+	set.Parse(args)
+	if set.NArg() != 2 {
 		fmt.Fprintln(os.Stderr, "usage: gasm diff <file1.s> <file2.s>")
 		return 2
 	}
-	path1, path2 := fs.Arg(0), fs.Arg(1)
+	path1, path2 := set.Arg(0), set.Arg(1)
 
 	// Parse the name mapping (file1 name → file2 name).
 	nameMap := make(map[string]string)
@@ -640,7 +640,7 @@ e.g. --map wideCopyAVX2=wideCopyAVX512 pairs the two regardless of suffix.
 }
 
 // assembleFile assembles a parsed file for the given architecture and returns the image.
-func assembleFile(path string, targetArch arch.Arch, f *ast.File) (*asm.Image, error) {
+func assembleFile(targetArch arch.Arch, f *ast.File) (*asm.Image, error) {
 	switch targetArch {
 	case arch.AMD64:
 		return asm.AssembleFile(f)
@@ -668,7 +668,7 @@ func assemblePath(path string) (*asm.Image, error) {
 	if len(errs) > 0 {
 		return nil, fmt.Errorf("parse errors")
 	}
-	return assembleFile(path, arch.FromFilename(path), f)
+	return assembleFile(arch.FromFilename(path), f)
 }
 
 // printByteDiff shows the first few byte differences between two code blocks.
@@ -688,18 +688,18 @@ func printByteDiff(a, b []byte) {
 
 // cmdProfile shows the basic-block structure of functions in an assembly file.
 func cmdProfile(args []string) int {
-	fs := newCommand("profile", "gasm profile <file.s>", `
+	flagSet := newCommand("profile", "gasm profile <file.s>", `
 Show the basic-block structure of functions in an assembly file.
 Lists each function's labels, their offsets, and the block boundaries.
 This is the static structure; for runtime execution counts, use
 gasm verify --fuzz which exercises the code paths.
 `)
-	fs.Parse(args)
-	if fs.NArg() != 1 {
+	flagSet.Parse(args)
+	if flagSet.NArg() != 1 {
 		fmt.Fprintln(os.Stderr, "usage: gasm profile <file.s>")
 		return 2
 	}
-	path := fs.Arg(0)
+	path := flagSet.Arg(0)
 
 	// Load the file to get function metadata.
 	k, err := verify.Load(path)
@@ -1021,7 +1021,7 @@ func cmdVerifyARM64(path string, groundTruth, profile bool) int {
 }
 
 func cmdVerify(args []string) int {
-	fs := newCommand("verify", "gasm verify [-smoke] [-abi] [-fuzz] [-ground-truth] [-profile] [-call] <file.s>", `
+	set := newCommand("verify", "gasm verify [-smoke] [-abi] [-fuzz] [-ground-truth] [-profile] [-call] <file.s>", `
 Assemble FILE (amd64), map it into executable memory and report the available
 functions.  This confirms the assembled image is self-consistent (no
 unresolved external symbols) and executable — the prerequisite for dynamic
@@ -1047,25 +1047,25 @@ With -call, a single function is invoked with user-supplied buffers (-buf)
 instead of the smoke/abi/fuzz sweeps.  Useful for partial functions (e.g.
 decoders) that crash on random input but should succeed on valid data.
 `)
-	smoke := fs.Bool("smoke", false, "call each NOSPLIT function with zeroed args")
-	abi := fs.Bool("abi", false, "run ABI-checking calls (sentinel registers + red zone)")
-	abiN := fs.Int("abi-n", 100, "number of ABI check iterations with varied inputs")
-	profile := fs.Bool("profile", false, "list basic-block structure per function")
-	groundTruth := fs.Bool("ground-truth", false, "compare machine code byte-for-byte against go tool asm")
-	fuzz := fs.Bool("fuzz", false, "differential fuzz: JIT both gasm and go-tool-asm versions, compare outputs")
-	fuzzN := fs.Int("n", 1000, "number of fuzz iterations per function")
-	fuzzOne := fs.String("fuzz-one", "", "")   // hidden: fuzz a single function (subprocess mode)
-	sweepOne := fs.String("sweep-one", "", "") // hidden: smoke/abi a single function (subprocess mode)
-	call := fs.String("call", "", "call a single function with -buf instead of the sweeps")
-	bufSpec := fs.String("buf", "", "buffer spec for -call: name:size:pattern[,name:size:pattern] (zero, ones, seq, or hex)")
-	scalarSpec := fs.String("args", "", "scalar args for -call: name=value[,name=value] (decimal or 0x hex)")
-	repeat := fs.Int("repeat", 1, "number of times to repeat a -call invocation")
-	fs.Parse(args)
-	if fs.NArg() != 1 {
+	smoke := set.Bool("smoke", false, "call each NOSPLIT function with zeroed args")
+	abi := set.Bool("abi", false, "run ABI-checking calls (sentinel registers + red zone)")
+	abiN := set.Int("abi-n", 100, "number of ABI check iterations with varied inputs")
+	profile := set.Bool("profile", false, "list basic-block structure per function")
+	groundTruth := set.Bool("ground-truth", false, "compare machine code byte-for-byte against go tool asm")
+	fuzz := set.Bool("fuzz", false, "differential fuzz: JIT both gasm and go-tool-asm versions, compare outputs")
+	fuzzN := set.Int("n", 1000, "number of fuzz iterations per function")
+	fuzzOne := set.String("fuzz-one", "", "")   // hidden: fuzz a single function (subprocess mode)
+	sweepOne := set.String("sweep-one", "", "") // hidden: smoke/abi a single function (subprocess mode)
+	call := set.String("call", "", "call a single function with -buf instead of the sweeps")
+	bufSpec := set.String("buf", "", "buffer spec for -call: name:size:pattern[,name:size:pattern] (zero, ones, seq, or hex)")
+	scalarSpec := set.String("args", "", "scalar args for -call: name=value[,name=value] (decimal or 0x hex)")
+	repeat := set.Int("repeat", 1, "number of times to repeat a -call invocation")
+	set.Parse(args)
+	if set.NArg() != 1 {
 		fmt.Fprintln(os.Stderr, "usage: gasm verify [-smoke] [-abi] [-fuzz] [-ground-truth] [-profile] [-call] <file.s>")
 		return 2
 	}
-	path := fs.Arg(0)
+	path := set.Arg(0)
 	targetArch := arch.FromFilename(path)
 	switch targetArch {
 	case arch.AMD64: