Builder: Emit metadata attachment for globals

Author: antlilja

src/codegen/llvm/Builder.zig

@@ -13853,16 +13853,12 @@ pub fn toBitcode(self: *Builder, allocator: Allocator) bitcode_writer.Error![]co
             try constants_block.end();
         }
 
-        const MetadataKind = enum(u8) {
-            dbg = 0,
-        };
-
         // METADATA_KIND_BLOCK
         if (!self.strip) {
             const MetadataKindBlock = ir.MetadataKindBlock;
             var metadata_kind_block = try module_block.enterSubBlock(MetadataKindBlock);
 
-            inline for (@typeInfo(MetadataKind).Enum.fields) |field| {
+            inline for (@typeInfo(ir.MetadataKind).Enum.fields) |field| {
                 try metadata_kind_block.writeAbbrev(MetadataKindBlock.Kind{
                     .id = field.value,
                     .name = field.name,
@@ -14296,6 +14292,51 @@ pub fn toBitcode(self: *Builder, allocator: Allocator) bitcode_writer.Error![]co
                 });
             }
 
+            // Write global attached metadata
+            {
+                for (self.variables.items) |variable| {
+                    if (variable.global.getReplacement(self) != .none) continue;
+
+                    const dbg = variable.global.ptrConst(self).dbg;
+
+                    if (dbg == .none) continue;
+
+                    try metadata_block.writeAbbrev(MetadataBlock.GlobalDeclAttachment{
+                        .value = @enumFromInt(constant_adapter.getConstantIndex(variable.global.toConst())),
+                        .kind = ir.MetadataKind.dbg,
+                        .metadata = @enumFromInt(metadata_adapter.getMetadataIndex(dbg) - 1),
+                    });
+                }
+
+                for (self.functions.items) |func| {
+                    if (func.global.getReplacement(self) != .none) continue;
+
+                    const dbg = func.global.ptrConst(self).dbg;
+
+                    if (dbg == .none or func.instructions.len != 0) continue;
+
+                    try metadata_block.writeAbbrev(MetadataBlock.GlobalDeclAttachment{
+                        .value = @enumFromInt(constant_adapter.getConstantIndex(func.global.toConst())),
+                        .kind = ir.MetadataKind.dbg,
+                        .metadata = @enumFromInt(metadata_adapter.getMetadataIndex(dbg) - 1),
+                    });
+                }
+
+                for (self.aliases.items) |alias| {
+                    if (alias.global.getReplacement(self) != .none) continue;
+
+                    const dbg = alias.global.ptrConst(self).dbg;
+
+                    if (dbg == .none) continue;
+
+                    try metadata_block.writeAbbrev(MetadataBlock.GlobalDeclAttachment{
+                        .value = @enumFromInt(constant_adapter.getConstantIndex(alias.global.toConst())),
+                        .kind = ir.MetadataKind.dbg,
+                        .metadata = @enumFromInt(metadata_adapter.getMetadataIndex(dbg) - 1),
+                    });
+                }
+            }
+
             try metadata_block.end();
         }
 
@@ -14909,7 +14950,7 @@ pub fn toBitcode(self: *Builder, allocator: Allocator) bitcode_writer.Error![]co
                     var metadata_attach_block = try function_block.enterSubBlock(MetadataAttachmentBlock);
 
                     try metadata_attach_block.writeAbbrev(MetadataAttachmentBlock.AttachmentSingle{
-                        .id = @intFromEnum(MetadataKind.dbg),
+                        .kind = ir.MetadataKind.dbg,
                         .metadata = @enumFromInt(metadata_adapter.getMetadataIndex(dbg) - 1),
                     });
 

src/codegen/llvm/ir.zig

@@ -20,6 +20,10 @@ const ColumnAbbrev = AbbrevOp{ .vbr = 8 };
 
 const BlockAbbrev = AbbrevOp{ .vbr = 6 };
 
+pub const MetadataKind = enum(u1) {
+    dbg = 0,
+};
+
 pub const Identification = struct {
     pub const id = 13;
 
@@ -616,10 +620,10 @@ pub const MetadataAttachmentBlock = struct {
     pub const AttachmentSingle = struct {
         pub const ops = [_]AbbrevOp{
             .{ .literal = 11 },
-            .{ .vbr = 4 },
+            .{ .fixed = 1 },
             MetadataAbbrev,
         };
-        id: u32,
+        kind: MetadataKind,
         metadata: Builder.Metadata,
     };
 };
@@ -649,6 +653,7 @@ pub const MetadataBlock = struct {
         Constant,
         Name,
         NamedNode,
+        GlobalDeclAttachment,
     };
 
     pub const Strings = struct {
@@ -1045,6 +1050,19 @@ pub const MetadataBlock = struct {
 
         elements: []const Builder.Metadata,
     };
+
+    pub const GlobalDeclAttachment = struct {
+        pub const ops = [_]AbbrevOp{
+            .{ .literal = 36 },
+            ValueAbbrev, // value id
+            .{ .fixed = 1 }, // kind
+            MetadataAbbrev, // elements
+        };
+
+        value: Builder.Constant,
+        kind: MetadataKind,
+        metadata: Builder.Metadata,
+    };
 };
 
 pub const FunctionMetadataBlock = struct {