SPIR-V: Restructure codegen a bit

src/codegen/spirv.zig

@@ -6,6 +6,7 @@ const spec = @import("spirv/spec.zig");
 const Module = @import("../Module.zig");
 const Decl = Module.Decl;
 const Type = @import("../type.zig").Type;
+const LazySrcLoc = Module.LazySrcLoc;
 
 pub const TypeMap = std.HashMap(Type, u32, Type.hash, Type.eql, std.hash_map.default_max_load_percentage);
 
@@ -15,30 +16,24 @@ pub fn writeInstruction(code: *std.ArrayList(u32), instr: spec.Opcode, args: []c
     try code.appendSlice(args);
 }
 
+/// This structure represents a SPIR-V binary module being compiled, and keeps track of relevant information
+/// such as code for the different logical sections, and the next result-id.
 pub const SPIRVModule = struct {
-    next_result_id: u32 = 0,
-
-    target: std.Target,
-
-    types: TypeMap,
-
+    next_result_id: u32,
     types_and_globals: std.ArrayList(u32),
     fn_decls: std.ArrayList(u32),
 
-    pub fn init(target: std.Target, allocator: *Allocator) SPIRVModule {
+    pub fn init(allocator: *Allocator) SPIRVModule {
         return .{
-            .target = target,
-            .types = TypeMap.init(allocator),
+            .next_result_id = 0,
             .types_and_globals = std.ArrayList(u32).init(allocator),
             .fn_decls = std.ArrayList(u32).init(allocator),
         };
     }
 
     pub fn deinit(self: *SPIRVModule) void {
-        self.fn_decls.deinit();
         self.types_and_globals.deinit();
-        self.types.deinit();
-        self.* = undefined;
+        self.fn_decls.deinit();
     }
 
     pub fn allocResultId(self: *SPIRVModule) u32 {
@@ -49,21 +44,40 @@ pub const SPIRVModule = struct {
     pub fn resultIdBound(self: *SPIRVModule) u32 {
         return self.next_result_id;
     }
+};
 
-    pub fn getOrGenType(self: *SPIRVModule, t: Type) !u32 {
+/// This structure is used to compile a declaration, and contains all relevant meta-information to deal with that.
+pub const DeclGen = struct {
+    module: *Module,
+    spv: *SPIRVModule,
+
+    types: TypeMap,
+
+    decl: *Decl,
+    error_msg: ?*Module.ErrorMsg,
+
+    fn fail(self: *DeclGen, src: LazySrcLoc, comptime format: []const u8, args: anytype) error{ AnalysisFail, OutOfMemory } {
+        @setCold(true);
+        const src_loc = src.toSrcLocWithDecl(self.decl);
+        self.error_msg = try Module.ErrorMsg.create(self.module.gpa, src_loc, format, args);
+        return error.AnalysisFail;
+    }
+
+    pub fn getOrGenType(self: *DeclGen, t: Type) !u32 {
         // We can't use getOrPut here so we can recursively generate types.
         if (self.types.get(t)) |already_generated| {
             return already_generated;
         }
 
-        const result = self.allocResultId();
+        const result = self.spv.allocResultId();
 
         switch (t.zigTypeTag()) {
-            .Void => try writeInstruction(&self.types_and_globals, .OpTypeVoid, &[_]u32{ result }),
-            .Bool => try writeInstruction(&self.types_and_globals, .OpTypeBool, &[_]u32{ result }),
+            .Void => try writeInstruction(&self.spv.types_and_globals, .OpTypeVoid, &[_]u32{ result }),
+            .Bool => try writeInstruction(&self.spv.types_and_globals, .OpTypeBool, &[_]u32{ result }),
             .Int => {
-                const int_info = t.intInfo(self.target);
-                try writeInstruction(&self.types_and_globals, .OpTypeInt, &[_]u32{
+                const int_info = t.intInfo(self.module.getTarget());
+                // TODO: Capabilities.
+                try writeInstruction(&self.spv.types_and_globals, .OpTypeInt, &[_]u32{
                     result,
                     int_info.bits,
                     switch (int_info.signedness) {
@@ -72,8 +86,8 @@ pub const SPIRVModule = struct {
                     },
                 });
             },
-            // TODO: Verify that floatBits() will be correct.
-            .Float => try writeInstruction(&self.types_and_globals, .OpTypeFloat, &[_]u32{ result, t.floatBits(self.target) }),
+            // TODO: Capabilities.
+            .Float => try writeInstruction(&self.spv.types_and_globals, .OpTypeFloat, &[_]u32{ result, t.floatBits(self.module.getTarget()) }),
             .Null,
             .Undefined,
             .EnumLiteral,
@@ -84,23 +98,23 @@ pub const SPIRVModule = struct {
 
             .BoundFn => unreachable, // this type will be deleted from the language.
 
-            else => return error.TODO,
+            else => |tag| return self.fail(.{ .node_offset = 0 }, "TODO: SPIR-V backend: implement type with tag {}", .{ tag }),
         }
 
         try self.types.put(t, result);
         return result;
     }
 
-    pub fn gen(self: *SPIRVModule, decl: *Decl) !void {
-        const typed_value = decl.typed_value.most_recent.typed_value;
+    pub fn gen(self: *DeclGen) !void {
+        const typed_value = self.decl.typed_value.most_recent.typed_value;
 
         switch (typed_value.ty.zigTypeTag()) {
             .Fn => {
-                log.debug("Generating code for function '{s}'", .{ std.mem.spanZ(decl.name) });
+                log.debug("Generating code for function '{s}'", .{ std.mem.spanZ(self.decl.name) });
 
                 _ = try self.getOrGenType(typed_value.ty.fnReturnType());
             },
-            else => return error.TODO,
+            else => |tag| return self.fail(.{ .node_offset = 0 }, "TODO: SPIR-V backend: generate decl with tag {}", .{ tag }),
         }
     }
 };