Commit 196ba706a0

@@ -15,7 +15,7 @@ const Allocator = std.mem.Allocator;
 const leb = std.leb;
 const meta = std.meta;
 
-const log = std.log.scoped(.link);
+const log = std.log.scoped(.object);
 
 /// Index into the list of relocatable object files within the linker driver.
 index: File.Index = .null,

@@ -315,7 +315,7 @@ fn finishUpdateDecl(
     const atom_index = decl_info.atom;
     const atom = wasm_file.getAtomPtr(atom_index);
     const sym = zig_object.symbol(atom.sym_index);
-    const full_name = mod.intern_pool.stringToSlice(try decl.getFullyQualifiedName(mod));
+    const full_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
     sym.name = try zig_object.string_table.insert(gpa, full_name);
     try atom.code.appendSlice(gpa, code);
     atom.size = @intCast(code.len);
@@ -401,7 +401,7 @@ pub fn getOrCreateAtomForDecl(zig_object: *ZigObject, wasm_file: *Wasm, decl_ind
         gop.value_ptr.* = .{ .atom = try wasm_file.createAtom(sym_index, zig_object.index) };
         const mod = wasm_file.base.comp.module.?;
         const decl = mod.declPtr(decl_index);
-        const full_name = mod.intern_pool.stringToSlice(try decl.getFullyQualifiedName(mod));
+        const full_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
         const sym = zig_object.symbol(sym_index);
         sym.name = try zig_object.string_table.insert(gpa, full_name);
     }
@@ -455,7 +455,7 @@ pub fn lowerUnnamedConst(zig_object: *ZigObject, wasm_file: *Wasm, tv: TypedValu
     const parent_atom_index = try zig_object.getOrCreateAtomForDecl(wasm_file, decl_index);
     const parent_atom = wasm_file.getAtom(parent_atom_index);
     const local_index = parent_atom.locals.items.len;
-    const fqn = mod.intern_pool.stringToSlice(try decl.getFullyQualifiedName(mod));
+    const fqn = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
     const name = try std.fmt.allocPrintZ(gpa, "__unnamed_{s}_{d}", .{
         fqn, local_index,
     });
@@ -838,6 +838,7 @@ pub fn updateExports(
     const atom = wasm_file.getAtom(atom_index);
     const atom_sym = atom.symbolLoc().getSymbol(wasm_file).*;
     const gpa = mod.gpa;
+    log.debug("Updating exports for decl '{s}'", .{mod.intern_pool.stringToSlice(decl.name)});
 
     for (exports) |exp| {
         if (mod.intern_pool.stringToSliceUnwrap(exp.opts.section)) |section| {
@@ -888,6 +889,7 @@ pub fn updateExports(
         if (exp.opts.visibility == .hidden) {
             sym.setFlag(.WASM_SYM_VISIBILITY_HIDDEN);
         }
+        log.debug("  with name '{s}' - {}", .{ export_string, sym });
         try zig_object.global_syms.put(gpa, export_name, sym_index);
         try wasm_file.symbol_atom.put(gpa, .{ .file = zig_object.index, .index = sym_index }, atom_index);
     }
@@ -1061,7 +1063,7 @@ pub fn createDebugSectionForIndex(zig_object: *ZigObject, wasm_file: *Wasm, inde
 pub fn updateDeclLineNumber(zig_object: *ZigObject, mod: *Module, decl_index: InternPool.DeclIndex) !void {
     if (zig_object.dwarf) |*dw| {
         const decl = mod.declPtr(decl_index);
-        const decl_name = mod.intern_pool.stringToSlice(try decl.getFullyQualifiedName(mod));
+        const decl_name = mod.intern_pool.stringToSlice(try decl.fullyQualifiedName(mod));
 
         log.debug("updateDeclLineNumber {s}{*}", .{ decl_name, decl });
         try dw.updateDeclLineNumber(mod, decl_index);

@@ -11,6 +11,7 @@ const leb = std.leb;
 const link = @import("../link.zig");
 const lldMain = @import("../main.zig").lldMain;
 const log = std.log.scoped(.link);
+const gc_log = std.log.scoped(.gc);
 const mem = std.mem;
 const trace = @import("../tracy.zig").trace;
 const types = @import("Wasm/types.zig");
@@ -525,6 +526,7 @@ pub fn createEmpty(
             const symbol = loc.getSymbol(wasm);
             symbol.setFlag(.WASM_SYM_VISIBILITY_HIDDEN);
             symbol.index = @intCast(wasm.imported_globals_count + wasm.wasm_globals.items.len);
+            symbol.mark();
             try wasm.wasm_globals.append(gpa, .{
                 .global_type = .{ .valtype = .i32, .mutable = true },
                 .init = .{ .i32_const = undefined },
@@ -535,6 +537,7 @@ pub fn createEmpty(
             const symbol = loc.getSymbol(wasm);
             symbol.setFlag(.WASM_SYM_VISIBILITY_HIDDEN);
             symbol.index = @intCast(wasm.imported_globals_count + wasm.wasm_globals.items.len);
+            symbol.mark();
             try wasm.wasm_globals.append(gpa, .{
                 .global_type = .{ .valtype = .i32, .mutable = false },
                 .init = .{ .i32_const = undefined },
@@ -545,6 +548,7 @@ pub fn createEmpty(
             const symbol = loc.getSymbol(wasm);
             symbol.setFlag(.WASM_SYM_VISIBILITY_HIDDEN);
             symbol.index = @intCast(wasm.imported_globals_count + wasm.wasm_globals.items.len);
+            symbol.mark();
             try wasm.wasm_globals.append(gpa, .{
                 .global_type = .{ .valtype = .i32, .mutable = false },
                 .init = .{ .i32_const = undefined },
@@ -968,6 +972,8 @@ fn setupInitMemoryFunction(wasm: *Wasm) !void {
     if (!wasm.hasPassiveInitializationSegments()) {
         return;
     }
+    const sym_loc = try wasm.createSyntheticSymbol("__wasm_init_memory", .function);
+    sym_loc.getSymbol(wasm).mark();
 
     const flag_address: u32 = if (shared_memory) address: {
         // when we have passive initialization segments and shared memory
@@ -1130,7 +1136,8 @@ fn setupTLSRelocationsFunction(wasm: *Wasm) !void {
         return;
     }
 
-    // const loc = try wasm.createSyntheticSymbol("__wasm_apply_global_tls_relocs");
+    const loc = try wasm.createSyntheticSymbol("__wasm_apply_global_tls_relocs", .function);
+    loc.getSymbol(wasm).mark();
     var function_body = std.ArrayList(u8).init(gpa);
     defer function_body.deinit();
     const writer = function_body.writer();
@@ -1833,8 +1840,7 @@ fn createSyntheticFunction(
     function_body: *std.ArrayList(u8),
 ) !void {
     const gpa = wasm.base.comp.gpa;
-    const loc = wasm.findGlobalSymbol(symbol_name) orelse
-        try wasm.createSyntheticSymbol(symbol_name, .function);
+    const loc = wasm.findGlobalSymbol(symbol_name).?; // forgot to create symbol?
     const symbol = loc.getSymbol(wasm);
     if (symbol.isDead()) {
         return;
@@ -1884,6 +1890,9 @@ fn initializeTLSFunction(wasm: *Wasm) !void {
 
     if (!shared_memory) return;
 
+    // ensure function is marked as we must emit it
+    wasm.findGlobalSymbol("__wasm_init_tls").?.getSymbol(wasm).mark();
+
     var function_body = std.ArrayList(u8).init(gpa);
     defer function_body.deinit();
     const writer = function_body.writer();
@@ -1932,6 +1941,7 @@ fn initializeTLSFunction(wasm: *Wasm) !void {
     if (wasm.findGlobalSymbol("__wasm_apply_global_tls_relocs")) |loc| {
         try writer.writeByte(std.wasm.opcode(.call));
         try leb.writeULEB128(writer, loc.getSymbol(wasm).index);
+        loc.getSymbol(wasm).mark();
     }
 
     try writer.writeByte(std.wasm.opcode(.end));
@@ -2039,14 +2049,19 @@ fn mergeSections(wasm: *Wasm) !void {
                     // We found an alias to the same function, discard this symbol in favor of
                     // the original symbol and point the discard function to it. This ensures
                     // we only emit a single function, instead of duplicates.
-                    symbol.unmark();
-                    try wasm.discarded.putNoClobber(
-                        gpa,
-                        sym_loc,
-                        .{ .file = gop.key_ptr.*.file, .index = gop.value_ptr.*.sym_index },
-                    );
-                    try removed_duplicates.append(sym_loc);
-                    continue;
+                    // we favor keeping the global over a local.
+                    const original_loc: SymbolLoc = .{ .file = gop.key_ptr.file, .index = gop.value_ptr.sym_index };
+                    const original_sym = original_loc.getSymbol(wasm);
+                    if (original_sym.isLocal() and symbol.isGlobal()) {
+                        original_sym.unmark();
+                        try wasm.discarded.put(gpa, original_loc, sym_loc);
+                        try removed_duplicates.append(original_loc);
+                    } else {
+                        symbol.unmark();
+                        try wasm.discarded.putNoClobber(gpa, sym_loc, original_loc);
+                        try removed_duplicates.append(sym_loc);
+                        continue;
+                    }
                 }
                 gop.value_ptr.* = .{ .func = obj_file.function(sym_loc.index), .sym_index = sym_loc.index };
                 symbol.index = @as(u32, @intCast(gop.index)) + wasm.imported_functions_count;
@@ -2073,6 +2088,7 @@ fn mergeSections(wasm: *Wasm) !void {
     // For any removed duplicates, remove them from the resolved symbols list
     for (removed_duplicates.items) |sym_loc| {
         assert(wasm.resolved_symbols.swapRemove(sym_loc));
+        gc_log.debug("Removed duplicate for function '{s}'", .{sym_loc.getName(wasm)});
     }
 
     log.debug("Merged ({d}) functions", .{wasm.functions.count()});
@@ -2119,12 +2135,7 @@ fn mergeTypes(wasm: *Wasm) !void {
     log.debug("Completed merging and deduplicating types. Total count: ({d})", .{wasm.func_types.items.len});
 }
 
-fn setupExports(wasm: *Wasm) !void {
-    const comp = wasm.base.comp;
-    const gpa = comp.gpa;
-    if (comp.config.output_mode == .Obj) return;
-    log.debug("Building exports from symbols", .{});
-
+fn checkExportNames(wasm: *Wasm) !void {
     const force_exp_names = wasm.export_symbol_names;
     if (force_exp_names.len > 0) {
         var failed_exports = false;
@@ -2144,6 +2155,13 @@ fn setupExports(wasm: *Wasm) !void {
             return error.FlushFailure;
         }
     }
+}
+
+fn setupExports(wasm: *Wasm) !void {
+    const comp = wasm.base.comp;
+    const gpa = comp.gpa;
+    if (comp.config.output_mode == .Obj) return;
+    log.debug("Building exports from symbols", .{});
 
     for (wasm.resolved_symbols.keys()) |sym_loc| {
         const symbol = sym_loc.getSymbol(wasm);
@@ -2272,6 +2290,7 @@ fn setupMemory(wasm: *Wasm) !void {
         memory_ptr = mem.alignForward(u64, memory_ptr, 4);
         const loc = try wasm.createSyntheticSymbol("__wasm_init_memory_flag", .data);
         const sym = loc.getSymbol(wasm);
+        sym.mark();
         sym.virtual_address = @as(u32, @intCast(memory_ptr));
         memory_ptr += 4;
     }
@@ -2561,6 +2580,7 @@ pub fn flushModule(wasm: *Wasm, arena: Allocator, prog_node: *std.Progress.Node)
     if (comp.link_errors.items.len > 0) return error.FlushFailure;
     try wasm.resolveLazySymbols();
     try wasm.checkUndefinedSymbols();
+    try wasm.checkExportNames();
 
     try wasm.setupInitFunctions();
     if (comp.link_errors.items.len > 0) return error.FlushFailure;
@@ -4044,6 +4064,7 @@ fn mark(wasm: *Wasm, loc: SymbolLoc) !void {
         return;
     }
     symbol.mark();
+    gc_log.debug("Marked symbol '{s}'", .{loc.getName(wasm)});
     if (symbol.isUndefined()) {
         // undefined symbols do not have an associated `Atom` and therefore also
         // do not contain relocations.

@@ -19,12 +19,13 @@ fn add(b: *std.Build, test_step: *std.Build.Step, optimize: std.builtin.Optimize
         .name = "main",
         .root_source_file = .{ .path = "main.zig" },
         .optimize = optimize,
-        .target = .{ .cpu_arch = .wasm32, .os_tag = .freestanding },
+        .target = b.resolveTargetQuery(.{ .cpu_arch = .wasm32, .os_tag = .freestanding }),
         .strip = false,
     });
     lib.entry = .disabled;
     lib.use_llvm = false;
     lib.use_lld = false;
+    lib.root_module.export_symbol_names = &.{"foo"};
 
     const check = lib.checkObject();
     check.checkInHeaders();

@@ -13,7 +13,7 @@ pub fn build(b: *std.Build) void {
         .name = "lib",
         .root_source_file = .{ .path = "lib.zig" },
         .optimize = .ReleaseSafe, // to make the output deterministic in address positions
-        .target = .{ .cpu_arch = .wasm32, .os_tag = .freestanding },
+        .target = b.resolveTargetQuery(.{ .cpu_arch = .wasm32, .os_tag = .freestanding }),
     });
     lib.entry = .disabled;
     lib.use_lld = false;

@@ -11,37 +11,39 @@ pub fn build(b: *std.Build) void {
 }
 
 fn add(b: *std.Build, test_step: *std.Build.Step, optimize_mode: std.builtin.OptimizeMode) void {
-    const lib = b.addExecutable(.{
+    const exe = b.addExecutable(.{
         .name = "lib",
         .root_source_file = .{ .path = "lib.zig" },
-        .target = .{
+        .target = b.resolveTargetQuery(.{
             .cpu_arch = .wasm32,
             .cpu_model = .{ .explicit = &std.Target.wasm.cpu.mvp },
             .cpu_features_add = std.Target.wasm.featureSet(&.{ .atomics, .bulk_memory }),
             .os_tag = .freestanding,
-        },
+        }),
         .optimize = optimize_mode,
         .strip = false,
         .single_threaded = false,
     });
-    lib.entry = .disabled;
-    lib.use_lld = false;
-    lib.import_memory = true;
-    lib.export_memory = true;
-    lib.shared_memory = true;
-    lib.max_memory = 67108864;
-    lib.root_module.export_symbol_names = &.{"foo"};
+    exe.entry = .disabled;
+    exe.use_lld = false;
+    exe.import_memory = true;
+    exe.export_memory = true;
+    exe.shared_memory = true;
+    exe.max_memory = 67108864;
+    exe.root_module.export_symbol_names = &.{"foo"};
 
-    const check_lib = lib.checkObject();
+    const check_exe = exe.checkObject();
 
-    check_lib.checkStart("Section import");
-    check_lib.checkNext("entries 1");
-    check_lib.checkNext("module env");
-    check_lib.checkNext("name memory"); // ensure we are importing memory
+    check_exe.checkInHeaders();
+    check_exe.checkExact("Section import");
+    check_exe.checkExact("entries 1");
+    check_exe.checkExact("module env");
+    check_exe.checkExact("name memory"); // ensure we are importing memory
 
-    check_lib.checkStart("Section export");
-    check_lib.checkNext("entries 2");
-    check_lib.checkNext("name memory"); // ensure we also export memory again
+    check_exe.checkInHeaders();
+    check_exe.checkExact("Section export");
+    check_exe.checkExact("entries 2");
+    check_exe.checkExact("name memory"); // ensure we also export memory again
 
     // This section *must* be emit as the start function is set to the index
     // of __wasm_init_memory
@@ -49,49 +51,42 @@ fn add(b: *std.Build, test_step: *std.Build.Step, optimize_mode: std.builtin.Opt
     // This means we won't have __wasm_init_memory in such case, and therefore
     // should also not have a section "start"
     if (optimize_mode == .Debug) {
-        check_lib.checkStart("Section start");
+        check_exe.checkInHeaders();
+        check_exe.checkExact("Section start");
     }
 
     // This section is only and *must* be emit when shared-memory is enabled
     // release modes will have the TLS segment optimized out in our test-case.
     if (optimize_mode == .Debug) {
-        check_lib.checkStart("Section data_count");
-        check_lib.checkNext("count 3");
+        check_exe.checkInHeaders();
+        check_exe.checkExact("Section data_count");
+        check_exe.checkExact("count 1");
     }
 
-    check_lib.checkStart("Section custom");
-    check_lib.checkNext("name name");
-    check_lib.checkNext("type function");
+    check_exe.checkInHeaders();
+    check_exe.checkExact("Section custom");
+    check_exe.checkExact("name name");
+    check_exe.checkExact("type function");
     if (optimize_mode == .Debug) {
-        check_lib.checkNext("name __wasm_init_memory");
+        check_exe.checkExact("name __wasm_init_memory");
     }
-    check_lib.checkNext("name __wasm_init_tls");
-    check_lib.checkNext("type global");
+    check_exe.checkExact("name __wasm_init_tls");
+    check_exe.checkExact("type global");
 
     // In debug mode the symbol __tls_base is resolved to an undefined symbol
     // from the object file, hence its placement differs than in release modes
     // where the entire tls segment is optimized away, and tls_base will have
     // its original position.
-    if (optimize_mode == .Debug) {
-        check_lib.checkNext("name __tls_size");
-        check_lib.checkNext("name __tls_align");
-        check_lib.checkNext("name __tls_base");
-    } else {
-        check_lib.checkNext("name __tls_base");
-        check_lib.checkNext("name __tls_size");
-        check_lib.checkNext("name __tls_align");
-    }
+    check_exe.checkExact("name __tls_base");
+    check_exe.checkExact("name __tls_size");
+    check_exe.checkExact("name __tls_align");
 
-    check_lib.checkNext("type data_segment");
+    check_exe.checkExact("type data_segment");
     if (optimize_mode == .Debug) {
-        check_lib.checkNext("names 3");
-        check_lib.checkNext("index 0");
-        check_lib.checkNext("name .rodata");
-        check_lib.checkNext("index 1");
-        check_lib.checkNext("name .bss");
-        check_lib.checkNext("index 2");
-        check_lib.checkNext("name .tdata");
+        check_exe.checkExact("names 1");
+        check_exe.checkExact("index 0");
+        check_exe.checkExact("name .tdata");
     }
 
-    test_step.dependOn(&check_lib.step);
+    test_step.dependOn(&check_exe.step);
 }

@@ -13,31 +13,32 @@ pub fn build(b: *std.Build) void {
 }
 
 fn add(b: *std.Build, test_step: *std.Build.Step, optimize: std.builtin.OptimizeMode) void {
-    const lib = b.addExecutable(.{
+    const exe = b.addExecutable(.{
         .name = "lib",
         .root_source_file = .{ .path = "lib.zig" },
         .target = b.resolveTargetQuery(.{ .cpu_arch = .wasm32, .os_tag = .freestanding }),
         .optimize = optimize,
         .strip = false,
     });
-    lib.entry = .disabled;
-    lib.use_llvm = false;
-    lib.use_lld = false;
-    b.installArtifact(lib);
+    exe.entry = .disabled;
+    exe.use_llvm = false;
+    exe.use_lld = false;
+    exe.root_module.export_symbol_names = &.{"foo"};
+    b.installArtifact(exe);
 
-    const check_lib = lib.checkObject();
-    check_lib.checkInHeaders();
-    check_lib.checkExact("Section type");
+    const check_exe = exe.checkObject();
+    check_exe.checkInHeaders();
+    check_exe.checkExact("Section type");
     // only 2 entries, although we have more functions.
     // This is to test functions with the same function signature
     // have their types deduplicated.
-    check_lib.checkExact("entries 2");
-    check_lib.checkExact("params 1");
-    check_lib.checkExact("type i32");
-    check_lib.checkExact("returns 1");
-    check_lib.checkExact("type i64");
-    check_lib.checkExact("params 0");
-    check_lib.checkExact("returns 0");
+    check_exe.checkExact("entries 2");
+    check_exe.checkExact("params 1");
+    check_exe.checkExact("type i32");
+    check_exe.checkExact("returns 1");
+    check_exe.checkExact("type i64");
+    check_exe.checkExact("params 0");
+    check_exe.checkExact("returns 0");
 
-    test_step.dependOn(&check_lib.step);
+    test_step.dependOn(&check_exe.step);
 }

@@ -35,11 +35,10 @@ pub const cases = [_]Case{
     },
 
     // WASM Cases
-    // https://github.com/ziglang/zig/issues/16938
-    //.{
-    //    .build_root = "test/link/wasm/archive",
-    //    .import = @import("link/wasm/archive/build.zig"),
-    //},
+    .{
+        .build_root = "test/link/wasm/archive",
+        .import = @import("link/wasm/archive/build.zig"),
+    },
     .{
         .build_root = "test/link/wasm/basic-features",
         .import = @import("link/wasm/basic-features/build.zig"),
@@ -52,11 +51,10 @@ pub const cases = [_]Case{
         .build_root = "test/link/wasm/export",
         .import = @import("link/wasm/export/build.zig"),
     },
-    // https://github.com/ziglang/zig/issues/16937
-    //.{
-    //    .build_root = "test/link/wasm/export-data",
-    //    .import = @import("link/wasm/export-data/build.zig"),
-    //},
+    .{
+        .build_root = "test/link/wasm/export-data",
+        .import = @import("link/wasm/export-data/build.zig"),
+    },
     .{
         .build_root = "test/link/wasm/extern",
         .import = @import("link/wasm/extern/build.zig"),
@@ -81,6 +79,10 @@ pub const cases = [_]Case{
         .build_root = "test/link/wasm/segments",
         .import = @import("link/wasm/segments/build.zig"),
     },
+    .{
+        .build_root = "test/link/wasm/shared-memory",
+        .import = @import("link/wasm/shared-memory/build.zig"),
+    },
     .{
         .build_root = "test/link/wasm/stack_pointer",
         .import = @import("link/wasm/stack_pointer/build.zig"),