fix(native): unify legacy Mach-O platform interpretation

src/artifacts/apple/MachoLoadCommandReader.test.ts

@@ -108,6 +108,7 @@ it.each([
   { command: LC.VERSION_MIN_IPHONEOS, cpu: CPU.i386, platform: 7 },
   { command: LC.VERSION_MIN_IPHONEOS, cpu: CPU.x86_64, platform: 7 },
   { command: LC.VERSION_MIN_IPHONEOS, cpu: CPU.arm64, platform: 2 },
+  { command: LC.VERSION_MIN_TVOS, cpu: CPU.i386, platform: 3 },
   { command: LC.VERSION_MIN_TVOS, cpu: CPU.x86_64, platform: 8 },
   { command: LC.VERSION_MIN_TVOS, cpu: CPU.arm64, platform: 3 },
   { command: LC.VERSION_MIN_WATCHOS, cpu: CPU.i386, platform: 9 },

src/artifacts/apple/MachoLoadCommandReader.ts

@@ -4,6 +4,10 @@ import type {
   MachoSlice,
 } from "../../domain/apple/dylibResolution.js";
 import { machoCpuSubtypeBase } from "../../domain/apple/machoCpuIdentity.js";
+import {
+  legacyMachoPlatform,
+  type MachoVersionMinPlatform,
+} from "../../domain/apple/machoPlatform.js";
 import {
   machoLoadCommandAlignment,
   classifyFatContainerIdentity,
@@ -53,53 +57,18 @@ const LC_LOAD_UPWARD_DYLIB = 0x80000023;
 const LC_RPATH = 0x8000001c;
 const LC_DYLD_ENVIRONMENT = 0x27;
 const LC_CODE_SIGNATURE = 0x1d;
-const LC_VERSION_MIN_MACOSX = 0x24;
-const LC_VERSION_MIN_IPHONEOS = 0x25;
-const LC_VERSION_MIN_TVOS = 0x2f;
-const LC_VERSION_MIN_WATCHOS = 0x30;
 const LC_BUILD_VERSION = 0x32;
 
-// `mach-o/loader.h` `PLATFORM_*` numbers observed via Apple linker output.
-const PLATFORM_MACOS = 1;
-const PLATFORM_IOS = 2;
-const PLATFORM_TVOS = 3;
-const PLATFORM_WATCHOS = 4;
-const PLATFORM_IOSSIMULATOR = 7;
-const PLATFORM_TVOSSIMULATOR = 8;
-const PLATFORM_WATCHOSSIMULATOR = 9;
-
-const CPU_TYPE_I386 = 7;
-const CPU_TYPE_X86_64 = 0x01000007;
 const CPU_TYPE_ARM64 = 0x0100000c;
 
-/**
- * Legacy `LC_VERSION_MIN_*` commands predate explicit simulator platform
- * IDs. Per Apple's dyld rules the image CPU type distinguishes simulator
- * from device: Intel images are simulator, ARM images are device
- * (tvOS simulator applies to x86_64 only). `LC_BUILD_VERSION` platform
- * numbers are preserved verbatim; unknown future numbers stay unknown
- * downstream, never mapped to nearest.
- */
-const legacyVersionMinPlatform = (
-  command: number,
-  cpuType: number,
-): number | undefined => {
-  const isIntel = cpuType === CPU_TYPE_I386 || cpuType === CPU_TYPE_X86_64;
-  switch (command) {
-    case LC_VERSION_MIN_MACOSX:
-      return PLATFORM_MACOS;
-    case LC_VERSION_MIN_IPHONEOS:
-      return isIntel ? PLATFORM_IOSSIMULATOR : PLATFORM_IOS;
-    case LC_VERSION_MIN_TVOS:
-      return cpuType === CPU_TYPE_X86_64
-        ? PLATFORM_TVOSSIMULATOR
-        : PLATFORM_TVOS;
-    case LC_VERSION_MIN_WATCHOS:
-      return isIntel ? PLATFORM_WATCHOSSIMULATOR : PLATFORM_WATCHOS;
-    default:
-      return undefined;
-  }
-};
+/** loader.h command codes and their device platform identities. */
+const VERSION_MIN_PLATFORMS: ReadonlyMap<number, MachoVersionMinPlatform> =
+  new Map([
+    [0x24, 1], // LC_VERSION_MIN_MACOSX
+    [0x25, 2], // LC_VERSION_MIN_IPHONEOS
+    [0x2f, 3], // LC_VERSION_MIN_TVOS
+    [0x30, 4], // LC_VERSION_MIN_WATCHOS
+  ]);
 
 /** `mach-o/loader.h` `dylib_use_command`: `nameoff == 28` and this marker. */
 const DYLIB_USE_MARKER = 0x1a741800;
@@ -691,14 +660,14 @@ const decodeCommand = (
     slice.platforms.push(platform);
     return;
   }
-  const legacyPlatform = legacyVersionMinPlatform(command, slice.cpu_type);
+  const legacyPlatform = VERSION_MIN_PLATFORMS.get(command);
   if (legacyPlatform !== undefined) {
     if (body.byteLength < 16)
       throw new MachoFormatIssue(
         "malformed",
         `load command ${index} is too short for a version-min command`,
       );
-    slice.platforms.push(legacyPlatform);
+    slice.platforms.push(legacyMachoPlatform(legacyPlatform, slice.cpu_type));
     return;
   }
   if (command === LC_LAZY_LOAD_DYLIB_INFO)

src/domain/apple/machoPlatform.ts

@@ -0,0 +1,19 @@
+/** Device platform encoded by a legacy LC_VERSION_MIN_* command. */
+export type MachoVersionMinPlatform = 1 | 2 | 3 | 4;
+
+/**
+ * dyld derives legacy simulator platforms from the CPU type. tvOS uses
+ * x86_64 only; iOS and watchOS also recognize i386. Explicit LC_BUILD_VERSION
+ * platforms do not use this rule.
+ */
+export const legacyMachoPlatform = (
+  platform: MachoVersionMinPlatform,
+  cpuType: number | null,
+): number => {
+  if (platform === 3) return cpuType === 0x01000007 ? 8 : 3;
+  if (cpuType === 7 || cpuType === 0x01000007) {
+    if (platform === 2) return 7;
+    if (platform === 4) return 9;
+  }
+  return platform;
+};

src/native/parsers/otool.ts

@@ -1,3 +1,8 @@
+import {
+  legacyMachoPlatform,
+  type MachoVersionMinPlatform,
+} from "../../domain/apple/machoPlatform.js";
+
 interface ParsedSection {
   readonly segment: string;
   readonly name: string;
@@ -70,6 +75,14 @@ const DYLIB_FIELDS = [
 const DYLIB_ENCODING_FIELDS = ["time stamp", "options"];
 const EMPTY_VALUE_FIELDS = new Set(["options", "segname", "sectname"]);
 
+const VERSION_MIN_PLATFORMS: ReadonlyMap<string, MachoVersionMinPlatform> =
+  new Map([
+    ["LC_VERSION_MIN_MACOSX", 1],
+    ["LC_VERSION_MIN_IPHONEOS", 2],
+    ["LC_VERSION_MIN_TVOS", 3],
+    ["LC_VERSION_MIN_WATCHOS", 4],
+  ]);
+
 /**
  * Non-verbose otool prints LC_BUILD_VERSION platform and tool codes as
  * numbers. Name the codes declared in the SDK's <mach-o/loader.h>, without
@@ -408,8 +421,16 @@ const collectBuild = (
   }
   if (kind.startsWith("LC_VERSION_MIN_")) {
     const platform = kind.slice("LC_VERSION_MIN_".length) || null;
+    const devicePlatform = VERSION_MIN_PLATFORMS.get(kind);
+    const derivedPlatform =
+      devicePlatform === undefined
+        ? undefined
+        : legacyMachoPlatform(devicePlatform, state.cpuType);
     state.builds.push({
-      platform: legacySimulatorPlatform(platform, state.cpuType),
+      platform:
+        derivedPlatform === undefined || derivedPlatform === devicePlatform
+          ? platform
+          : buildCodeName(BUILD_PLATFORM_NAMES, String(derivedPlatform)),
       minimum_os: stringField(fields, "version"),
       sdk: stringField(fields, "sdk"),
       tools: [],
@@ -417,24 +438,6 @@ const collectBuild = (
   }
 };
 
-// Apple dyld interprets legacy iOS/tvOS/watchOS minimum-version commands on
-// Intel slices as simulator platforms. Newer commands encode this directly.
-const legacySimulatorPlatform = (
-  platform: string | null,
-  cpuType: number | null,
-): string | null => {
-  if (![7, 0x01000007].includes(cpuType ?? -1)) return platform;
-  return (
-    (
-      {
-        IPHONEOS: "IOSSIMULATOR",
-        TVOS: "TVOSSIMULATOR",
-        WATCHOS: "WATCHOSSIMULATOR",
-      } as const
-    )[platform as "IPHONEOS" | "TVOS" | "WATCHOS"] ?? platform
-  );
-};
-
 const collectDependency = (
   kind: string,
   fields: Readonly<Record<string, string | number | null>>,

tests/boundary/providers/native/nativeMachoHeader.golden.test.ts

@@ -269,33 +269,66 @@ Section
 });
 
 it.each([
-  ["LC_VERSION_MIN_IPHONEOS", "IOSSIMULATOR"],
-  ["LC_VERSION_MIN_TVOS", "TVOSSIMULATOR"],
-  ["LC_VERSION_MIN_WATCHOS", "WATCHOSSIMULATOR"],
-])("classifies legacy Intel simulator command %s", (command, platform) => {
+  ["LC_VERSION_MIN_IPHONEOS", 7, "IOSSIMULATOR"],
+  ["LC_VERSION_MIN_IPHONEOS", 16777223, "IOSSIMULATOR"],
+  ["LC_VERSION_MIN_IPHONEOS", 16777228, "IPHONEOS"],
+  ["LC_VERSION_MIN_TVOS", 7, "TVOS"],
+  ["LC_VERSION_MIN_TVOS", 16777223, "TVOSSIMULATOR"],
+  ["LC_VERSION_MIN_TVOS", 16777228, "TVOS"],
+  ["LC_VERSION_MIN_WATCHOS", 7, "WATCHOSSIMULATOR"],
+  ["LC_VERSION_MIN_WATCHOS", 16777223, "WATCHOSSIMULATOR"],
+  ["LC_VERSION_MIN_WATCHOS", 16777228, "WATCHOS"],
+  ["LC_VERSION_MIN_MACOSX", 7, "MACOSX"],
+  ["LC_VERSION_MIN_MACOSX", 16777223, "MACOSX"],
+  ["LC_VERSION_MIN_MACOSX", 16777228, "MACOSX"],
+])(
+  "classifies legacy command %s on CPU %s as %s",
+  (command, cpuType, platform) => {
+    const text = [
+      "Mach header",
+      "      magic cputype cpusubtype caps filetype ncmds sizeofcmds flags",
+      ` ${cpuType === 7 ? "0xfeedface" : "0xfeedfacf"} ${cpuType} 3 0x00 2 1 16 0x0`,
+      "Load command 0",
+      `      cmd ${command}`,
+      "  cmdsize 16",
+      "   version 12.0",
+      "       sdk 12.1",
+    ].join("\n");
+    expect(parseOtoolLoadCommands(text).builds[0]?.platform).toBe(platform);
+  },
+);
+
+it.each([
+  ["3", "TVOS"],
+  ["4294967295", "4294967295"],
+])("preserves explicit build platform %s on Intel", (code, platform) => {
+  const text = [
+    "Mach header",
+    "      magic cputype cpusubtype caps filetype ncmds sizeofcmds flags",
+    " 0xfeedfacf 16777223 3 0x00 2 1 24 0x0",
+    "Load command 0",
+    "      cmd LC_BUILD_VERSION",
+    "  cmdsize 24",
+    ` platform ${code}`,
+    "    minos 12.0",
+    "      sdk 12.1",
+    "   ntools 0",
+  ].join("\n");
+  expect(parseOtoolLoadCommands(text).builds[0]?.platform).toBe(platform);
+});
+
+it("preserves an unknown legacy platform spelling on Intel", () => {
   const text = [
     "Mach header",
     "      magic cputype cpusubtype caps filetype ncmds sizeofcmds flags",
     " 0xfeedfacf 16777223 3 0x00 2 1 16 0x0",
     "Load command 0",
-    `      cmd ${command}`,
+    "      cmd LC_VERSION_MIN_FUTURE",
     "  cmdsize 16",
     "   version 12.0",
     "       sdk 12.1",
   ].join("\n");
-  expect(parseOtoolLoadCommands(text).builds[0]?.platform).toBe(platform);
-});
-
-it("keeps legacy device platforms on arm64 slices", () => {
-  const text = [
-    "Mach header",
-    "      magic cputype cpusubtype caps filetype ncmds sizeofcmds flags",
-    " 0xfeedfacf 16777228 0 0x00 2 1 16 0x0",
-    "Load command 0",
-    "      cmd LC_VERSION_MIN_IPHONEOS",
-    "  cmdsize 16",
-    "   version 12.0",
-    "       sdk 12.1",
-  ].join("\n");
-  expect(parseOtoolLoadCommands(text).builds[0]?.platform).toBe("IPHONEOS");
+  const result = parseOtoolLoadCommands(text);
+  expect(result.builds[0]?.platform).toBe("FUTURE");
+  expect(result.commands[0]?.kind).toBe("LC_VERSION_MIN_FUTURE");
 });