refactor: neutralize bmi_cache naming for GCC/Clang parity

Rename gcmFiles→bmiFiles, gcmDir()→bmiDir(), add bmiDirName/manifestTag
fields to CacheKey. Manifest format now uses the tag from CacheKey
(gcm: or pcm:) and parsing accepts both prefixes for forward compat.

Callers set bmiDirName/manifestTag via BmiTraits from PR1.

Author: Sunrisepeak

src/bmi_cache.cppm

@@ -2,7 +2,7 @@
 //
 // Layout (per docs/26-bmi-cache.md):
 //   $MCPP_HOME/bmi/<fingerprint>/deps/<indexName>/<pkgName>@<version>/
-//     gcm.cache/<module>.gcm
+//     {gcm,pcm}.cache/<module>.{gcm,pcm}
 //     obj/<file>.m.o + <file>.o
 //     manifest.txt    (sentinel + file list)
 //
@@ -31,20 +31,22 @@ struct CacheKey {
     std::string indexName;       // "mcpplibs" / "xim" / ...
     std::string packageName;     // "mcpplibs.cmdline"
     std::string version;         // "0.0.1"
+    std::string bmiDirName   = "gcm.cache"; // "gcm.cache" | "pcm.cache"
+    std::string manifestTag  = "gcm";       // "gcm" | "pcm"
 
     std::filesystem::path dir() const {
         return mcppHome / "bmi" / fingerprint / "deps"
              / indexName / std::format("{}@{}", packageName, version);
     }
 
     std::filesystem::path manifestFile() const { return dir() / "manifest.txt"; }
-    std::filesystem::path gcmDir()      const { return dir() / "gcm.cache"; }
+    std::filesystem::path bmiDir()      const { return dir() / bmiDirName; }
     std::filesystem::path objDir()      const { return dir() / "obj"; }
 };
 
 // File names (basename only) that belong to one dep package's cache entry.
 struct DepArtifacts {
-    std::vector<std::string> gcmFiles;   // basenames in gcm.cache/
+    std::vector<std::string> bmiFiles;   // basenames in bmiDir/
     std::vector<std::string> objFiles;   // basenames in obj/
 };
 
@@ -55,14 +57,14 @@ bool is_cached(const CacheKey& key);
 std::expected<DepArtifacts, std::string>
 read_manifest(const CacheKey& key);
 
-// Copy missing cached files into projectTarget/{gcm.cache,obj}. Existing
-// project outputs are left untouched: GCC BMIs may differ byte-for-byte between
+// Copy missing cached files into projectTarget/{bmiDirName,obj}. Existing
+// project outputs are left untouched: BMIs may differ byte-for-byte between
 // equivalent builds, and overwriting them would dirty downstream modules.
 std::expected<DepArtifacts, std::string>
 stage_into(const CacheKey& key,
            const std::filesystem::path& projectTargetDir);
 
-// Copy fresh build outputs from projectTarget/{gcm.cache,obj} → cache dir
+// Copy fresh build outputs from projectTarget/{bmiDirName,obj} → cache dir
 // and write manifest.txt last (atomic-ish sentinel).
 std::expected<void, std::string>
 populate_from(const CacheKey& key,
@@ -91,9 +93,9 @@ bool copy_one(const std::filesystem::path& from,
     return !ec;
 }
 
-std::string serialize_manifest(const DepArtifacts& a) {
+std::string serialize_manifest(std::string_view tag, const DepArtifacts& a) {
     std::string out = "# Auto-generated by mcpp bmi_cache. Do not edit.\n";
-    for (auto& g : a.gcmFiles) out += std::format("gcm: {}\n", g);
+    for (auto& g : a.bmiFiles) out += std::format("{}: {}\n", tag, g);
     for (auto& o : a.objFiles) out += std::format("obj: {}\n", o);
     return out;
 }
@@ -107,7 +109,8 @@ parse_manifest(const std::filesystem::path& p) {
     while (std::getline(is, line)) {
         while (!line.empty() && (line.back() == '\r' || line.back() == ' ')) line.pop_back();
         if (line.empty() || line[0] == '#') continue;
-        if (line.starts_with("gcm: ")) a.gcmFiles.push_back(line.substr(5));
+        if (line.starts_with("gcm: "))      a.bmiFiles.push_back(line.substr(5));
+        else if (line.starts_with("pcm: ")) a.bmiFiles.push_back(line.substr(5));
         else if (line.starts_with("obj: ")) a.objFiles.push_back(line.substr(5));
     }
     return a;
@@ -121,8 +124,8 @@ bool is_cached(const CacheKey& key) {
     auto arts = parse_manifest(mf);
     if (!arts) return false;
     // Verify every listed file actually exists on disk.
-    for (auto& g : arts->gcmFiles) {
-        if (!std::filesystem::exists(key.gcmDir() / g)) return false;
+    for (auto& g : arts->bmiFiles) {
+        if (!std::filesystem::exists(key.bmiDir() / g)) return false;
     }
     for (auto& o : arts->objFiles) {
         if (!std::filesystem::exists(key.objDir() / o)) return false;
@@ -142,23 +145,23 @@ stage_into(const CacheKey& key,
     auto arts = parse_manifest(key.manifestFile());
     if (!arts) return std::unexpected(arts.error());
 
-    auto projectGcm = projectTargetDir / "gcm.cache";
+    auto projectBmi = projectTargetDir / key.bmiDirName;
     auto projectObj = projectTargetDir / "obj";
     std::error_code ec;
-    std::filesystem::create_directories(projectGcm, ec);
+    std::filesystem::create_directories(projectBmi, ec);
     std::filesystem::create_directories(projectObj, ec);
 
-    for (auto& g : arts->gcmFiles) {
-        auto from = key.gcmDir() / g;
-        auto to   = projectGcm   / g;
+    for (auto& g : arts->bmiFiles) {
+        auto from = key.bmiDir() / g;
+        auto to   = projectBmi   / g;
         if (std::filesystem::exists(to, ec)) {
             ec.clear();
             continue;
         }
         ec.clear();
         if (!copy_one(from, to, ec)) {
             return std::unexpected(std::format(
-                "stage gcm '{}': {}", g, ec.message()));
+                "stage bmi '{}': {}", g, ec.message()));
         }
         touch_now(to);
     }
@@ -221,25 +224,25 @@ populate_from(const CacheKey& key,
         ~LockGuard() { release_lock(fd); }
     } guard{ lockFd };
 
-    auto cacheGcm = key.gcmDir();
+    auto cacheBmi = key.bmiDir();
     auto cacheObj = key.objDir();
     std::error_code ec;
-    std::filesystem::create_directories(cacheGcm, ec);
+    std::filesystem::create_directories(cacheBmi, ec);
     std::filesystem::create_directories(cacheObj, ec);
 
-    auto projectGcm = projectTargetDir / "gcm.cache";
+    auto projectBmi = projectTargetDir / key.bmiDirName;
     auto projectObj = projectTargetDir / "obj";
 
-    for (auto& g : arts.gcmFiles) {
-        auto from = projectGcm / g;
-        auto to   = cacheGcm   / g;
+    for (auto& g : arts.bmiFiles) {
+        auto from = projectBmi / g;
+        auto to   = cacheBmi   / g;
         if (!std::filesystem::exists(from)) {
             return std::unexpected(std::format(
                 "expected build output missing: {}", from.string()));
         }
         if (!copy_one(from, to, ec)) {
             return std::unexpected(std::format(
-                "populate gcm '{}': {}", g, ec.message()));
+                "populate bmi '{}': {}", g, ec.message()));
         }
     }
     for (auto& o : arts.objFiles) {
@@ -260,7 +263,7 @@ populate_from(const CacheKey& key,
         tmp += ".tmp";
         {
             std::ofstream os(tmp);
-            os << serialize_manifest(arts);
+            os << serialize_manifest(key.manifestTag, arts);
         }
         std::filesystem::rename(tmp, key.manifestFile(), ec);
         if (ec) {

src/cli.cppm

@@ -2023,12 +2023,15 @@ prepare_build(bool print_fingerprint,
             }
             if (skipCache) continue;
 
+            auto bmiT = mcpp::toolchain::bmi_traits(*tc);
             mcpp::bmi_cache::CacheKey key {
                 .mcppHome    = (*cfg2)->mcppHome,
                 .fingerprint = fp.hex,
                 .indexName   = (*cfg2)->defaultIndex,
                 .packageName = depName,
                 .version     = depVer,
+                .bmiDirName  = std::string(bmiT.bmiDir),
+                .manifestTag = std::string(bmiT.manifestPrefix),
             };
 
             // Compute the artifacts list from the build plan: every
@@ -2042,11 +2045,11 @@ prepare_build(bool print_fingerprint,
                 if (rels.starts_with("..")) continue;       // not under depRoot
 
                 if (cu.providesModule) {
-                    std::string gcm;
+                    std::string bmi;
                     for (char c : *cu.providesModule)
-                        gcm.push_back(c == ':' ? '-' : c);
-                    gcm += ".gcm";
-                    arts.gcmFiles.push_back(std::move(gcm));
+                        bmi.push_back(c == ':' ? '-' : c);
+                    bmi += std::string(bmiT.bmiExt);
+                    arts.bmiFiles.push_back(std::move(bmi));
                 }
                 arts.objFiles.push_back(cu.object.filename().string());
             }

tests/unit/test_bmi_cache.cpp

@@ -46,7 +46,7 @@ TEST(BmiCache, KeyDirLayoutMatchesDocs26) {
     EXPECT_EQ(k.dir().string(),
               "/home/u/.mcpp/bmi/deadbeef0123abcd/deps/mcpplibs/mcpplibs.cmdline@0.0.1");
     EXPECT_EQ(k.manifestFile().filename().string(), "manifest.txt");
-    EXPECT_EQ(k.gcmDir().filename().string(),       "gcm.cache");
+    EXPECT_EQ(k.bmiDir().filename().string(),       "gcm.cache");
     EXPECT_EQ(k.objDir().filename().string(),       "obj");
 }
 
@@ -68,7 +68,7 @@ TEST(BmiCache, PopulateThenStageRoundTrip) {
     writeFile(project / "obj"       / "cmdline.m.o",                  "OBJ-A");
 
     DepArtifacts arts {
-        .gcmFiles = { "mcpplibs.cmdline.gcm", "mcpplibs.cmdline-options.gcm" },
+        .bmiFiles = { "mcpplibs.cmdline.gcm", "mcpplibs.cmdline-options.gcm" },
         .objFiles = { "cmdline.m.o" },
     };
 
@@ -77,16 +77,16 @@ TEST(BmiCache, PopulateThenStageRoundTrip) {
     ASSERT_TRUE(pop) << pop.error();
 
     EXPECT_TRUE(std::filesystem::exists(k.manifestFile()));
-    EXPECT_TRUE(std::filesystem::exists(k.gcmDir() / "mcpplibs.cmdline.gcm"));
-    EXPECT_TRUE(std::filesystem::exists(k.gcmDir() / "mcpplibs.cmdline-options.gcm"));
+    EXPECT_TRUE(std::filesystem::exists(k.bmiDir() / "mcpplibs.cmdline.gcm"));
+    EXPECT_TRUE(std::filesystem::exists(k.bmiDir() / "mcpplibs.cmdline-options.gcm"));
     EXPECT_TRUE(std::filesystem::exists(k.objDir() / "cmdline.m.o"));
     EXPECT_TRUE(is_cached(k));
 
     // Round-trip: stage into a fresh project dir.
     auto project2 = t.path / "proj2" / "target";
     auto staged = stage_into(k, project2);
     ASSERT_TRUE(staged) << staged.error();
-    EXPECT_EQ(staged->gcmFiles.size(), 2u);
+    EXPECT_EQ(staged->bmiFiles.size(), 2u);
     EXPECT_EQ(staged->objFiles.size(), 1u);
     EXPECT_TRUE(std::filesystem::exists(project2 / "gcm.cache" / "mcpplibs.cmdline.gcm"));
     EXPECT_TRUE(std::filesystem::exists(project2 / "obj"       / "cmdline.m.o"));
@@ -108,7 +108,7 @@ TEST(BmiCache, StageIntoDoesNotTouchIdenticalOutputs) {
     writeFile(project / "obj"       / "cmdline.m.o",          "OBJ-A");
 
     DepArtifacts arts {
-        .gcmFiles = { "mcpplibs.cmdline.gcm" },
+        .bmiFiles = { "mcpplibs.cmdline.gcm" },
         .objFiles = { "cmdline.m.o" },
     };
 
@@ -140,7 +140,7 @@ TEST(BmiCache, StageIntoDoesNotOverwriteExistingOutputs) {
     writeFile(cacheProject / "obj"       / "cmdline.m.o",          "CACHE-OBJ");
 
     DepArtifacts arts {
-        .gcmFiles = { "mcpplibs.cmdline.gcm" },
+        .bmiFiles = { "mcpplibs.cmdline.gcm" },
         .objFiles = { "cmdline.m.o" },
     };
 
@@ -178,7 +178,7 @@ TEST(BmiCache, IsCachedFalseWhenSentinelExistsButFileMissing) {
     writeFile(project / "gcm.cache" / "lib.gcm", "G");
     writeFile(project / "obj"       / "lib.m.o", "O");
 
-    DepArtifacts arts { .gcmFiles = {"lib.gcm"}, .objFiles = {"lib.m.o"} };
+    DepArtifacts arts { .bmiFiles = {"lib.gcm"}, .objFiles = {"lib.m.o"} };
     auto k = makeKey(home);
     ASSERT_TRUE(populate_from(k, project, arts));
     ASSERT_TRUE(is_cached(k));
@@ -193,7 +193,7 @@ TEST(BmiCache, PopulateFailsIfBuildOutputMissing) {
     auto home    = t.path / "home";
     auto project = t.path / "proj" / "target";
     std::filesystem::create_directories(project / "gcm.cache");
-    DepArtifacts arts { .gcmFiles = {"missing.gcm"}, .objFiles = {} };
+    DepArtifacts arts { .bmiFiles = {"missing.gcm"}, .objFiles = {} };
     auto k = makeKey(home);
     auto pop = populate_from(k, project, arts);
     EXPECT_FALSE(pop);
@@ -219,7 +219,7 @@ TEST(BmiCache, PopulateSkipsWhenLockHeld) {
     ASSERT_GE(fd, 0);
     ASSERT_EQ(::flock(fd, LOCK_EX | LOCK_NB), 0);
 
-    DepArtifacts arts { .gcmFiles = {"lib.gcm"}, .objFiles = {"lib.m.o"} };
+    DepArtifacts arts { .bmiFiles = {"lib.gcm"}, .objFiles = {"lib.m.o"} };
     auto pop = populate_from(k, project, arts);
     EXPECT_TRUE(pop) << "should silently skip when lock is held";
     // manifest.txt must NOT have been written by the second writer.