emit metadata tables before the actual sysimage

Author: pchintalapudi

src/aotcompile.cpp

@@ -515,6 +515,29 @@ void jl_dump_native_impl(void *native_code,
                 DumpOutput{asm_Archive, asm_fname ? "text.s" : ""},
                 true, threads);
 
+    if (imaging_mode) {
+        bool has_veccall = false;
+        if (auto md = dataM->getModuleFlag("julia.mv.veccall")) {
+            has_veccall = cast<ConstantInt>(cast<ConstantAsMetadata>(md)->getValue())->isOneValue();
+        }
+        orc::ThreadSafeModule metadata(std::make_unique<Module>("metadata", Context), TSCtx);
+        auto metadataM = metadata.getModuleUnlocked();
+        metadataM->setTargetTriple(dataM->getTargetTriple());
+        metadataM->setDataLayout(dataM->getDataLayout());
+#if JL_LLVM_VERSION >= 130000
+        metadataM->setStackProtectorGuard(dataM->getStackProtectorGuard());
+        metadataM->setOverrideStackAlignment(dataM->getOverrideStackAlignment());
+#endif
+        metadataM->addModuleFlag(Module::ModFlagBehavior::Error, "julia.mv.disable", 1);
+        add_sysimage_targets(*metadataM, has_veccall, threads, data->jl_sysimg_fvars.size(), data->jl_sysimg_gvars.size(), T_pgcstack_getter->getPointerTo());
+        add_output(*TM, *metadataM, outputs,
+                    DumpOutput{unopt_bc_Archive, "metadata.bc"},
+                    DumpOutput{bc_Archive, "metadata.bc"},
+                    DumpOutput{obj_Archive, "metadata.o"},
+                    DumpOutput{asm_Archive, "metadata.s"},
+                    false, 1);
+    }
+
     orc::ThreadSafeModule sysimage(std::make_unique<Module>("sysimage", Context), TSCtx);
     auto sysimageM = sysimage.getModuleUnlocked();
     sysimageM->setTargetTriple(dataM->getTargetTriple());
@@ -523,13 +546,7 @@ void jl_dump_native_impl(void *native_code,
     sysimageM->setStackProtectorGuard(dataM->getStackProtectorGuard());
     sysimageM->setOverrideStackAlignment(dataM->getOverrideStackAlignment());
 #endif
-    if (imaging_mode) {
-        bool has_veccall = false;
-        if (auto md = dataM->getModuleFlag("julia.mv.veccall")) {
-            has_veccall = cast<ConstantInt>(cast<ConstantAsMetadata>(md)->getValue())->isOneValue();
-        }
-        add_sysimage_targets(*sysimageM, has_veccall, threads, data->jl_sysimg_fvars.size(), data->jl_sysimg_gvars.size(), T_pgcstack_getter->getPointerTo());
-    }
+    sysimageM->addModuleFlag(Module::ModFlagBehavior::Error, "julia.mv.disable", 1);
     data->M = orc::ThreadSafeModule(); // free memory for data->M
 
     if (sysimg_data) {

src/llvm-multiversioning.cpp

@@ -978,7 +978,8 @@ static bool runMultiVersioning(Module &M, bool allow_bad_fvars)
     //     * Cloned function -> Original function (add as we clone functions)
     //     * Original function -> Base function (target specific and updated by LLVM)
     //     * ID -> relocation slots (const).
-    if (M.getName() == "sysimage")
+    auto disable_mv = M.getModuleFlag("julia.mv.disable");
+    if (disable_mv && !cast<ConstantInt>(cast<ConstantAsMetadata>(disable_mv)->getValue())->isZero())
         return false;
 
     GlobalVariable *fvars = M.getGlobalVariable("jl_sysimg_fvars");

src/sysimg.cpp

@@ -1091,7 +1091,7 @@ unsigned compute_image_thread_count(Module &M) {
     unsigned max_threads = std::max(available / (weight * fudge), (size_t)1);
     dbgs() << "Weight: " << weight << ", available: " << available << ", wanted: " << threads << ", max threads: " << max_threads << "\n";
     threads = std::min(threads, max_threads);
-    
+
     // environment variable override
     const char *env_threads = getenv("JULIA_IMAGE_THREADS");
     if (env_threads) {