From bcda3eeb11caad6ac3d96a3eeebed3fef498ea6a Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Sat, 15 Aug 2020 23:51:37 +0200
Subject: [PATCH] Opcode rendering

---
 generator/spirv/generator.zig |  2 +-
 generator/spirv/render.zig    | 36 +++++++++++++++++++++++++++++------
 generator/vulkan/render.zig   |  2 +-
 3 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/generator/spirv/generator.zig b/generator/spirv/generator.zig
index d05545b..ea7d97b 100644
--- a/generator/spirv/generator.zig
+++ b/generator/spirv/generator.zig
@@ -69,5 +69,5 @@ pub fn generate(allocator: *Allocator, spec_jsons: []const []const u8, writer: a
     }
 
     const merged = try mergeRegistries(&arena.allocator, core_registry, ext_registries);
-    try renderSpirv(writer, &merged);
+    try renderSpirv(writer, &arena.allocator, &merged);
 }
diff --git a/generator/spirv/render.zig b/generator/spirv/render.zig
index c4dc288..6ec24e5 100644
--- a/generator/spirv/render.zig
+++ b/generator/spirv/render.zig
@@ -15,6 +15,20 @@ const tags = [_][]const u8{
     "NV",
 };
 
+const preamble =
+    \\
+    \\ This file is generated from the SPIR-V JSON registry
+    ;
+
+fn stripOpPrefix(name: []const u8) []const u8 {
+    // Some instructions (those from the core) are prefixed with 'Op'
+    const prefix = "Op";
+    return if (std.mem.startsWith(u8, name, prefix))
+            name[prefix.len ..]
+        else
+            name;
+}
+
 fn Renderer(comptime WriterType: type) type {
     return struct {
         const Self = @This();
@@ -23,23 +37,33 @@ fn Renderer(comptime WriterType: type) type {
         registry: *const reg.CoreRegistry,
         id_renderer: IdRenderer,
 
-        fn deinit(self: Self) void {
-
+        fn render(self: *Self) !void {
+            for (self.registry.copyright) |line| {
+                try self.writer.print("// {}\n", .{ line });
+            }
+            try self.writer.writeAll(preamble);
+            try self.renderOpcodes();
         }
 
-        fn render(self: *Self) !void {
-
+        fn renderOpcodes(self: *Self) !void {
+            try self.writer.writeAll("pub const Opcode = enum(u16) {\n");
+            for (self.registry.instructions) |instr| {
+                try self.id_renderer.renderWithCase(self.writer, .snake, stripOpPrefix(instr.opname));
+                try self.writer.print(" = {},\n", .{ instr.opcode });
+            }
+            try self.writer.writeAll("};\n");
         }
     };
 }
 
-pub fn render(writer: anytype, registry: *const reg.CoreRegistry) !void {
+pub fn render(writer: anytype, allocator: *Allocator, registry: *const reg.CoreRegistry) !void {
     const id_renderer = IdRenderer.init(allocator, &tags);
+    defer id_renderer.deinit();
     var renderer = Renderer(@TypeOf(writer)) {
         .writer = writer,
         .registry = registry,
         .id_renderer = id_renderer,
     };
-    defer renderer.deinit();
     try renderer.render();
 }
+
diff --git a/generator/vulkan/render.zig b/generator/vulkan/render.zig
index 94d7479..6a5e491 100644
--- a/generator/vulkan/render.zig
+++ b/generator/vulkan/render.zig
@@ -9,7 +9,7 @@ const IdRenderer = id_render.IdRenderer;
 
 const preamble =
     \\
-    \\// This file is generated from the Khronos Vulkan XML API Registry
+    \\// This file is generated from the Khronos Vulkan XML API registry
     \\
     \\const std = @import("std");
     \\const builtin = @import("builtin");