support --debug-dump-disasm

2 files changed, 44 insertions, 5 deletions

diff --git a/src/jq/codegen.zig b/src/jq/codegen.zig
index 23383bf..1fc889d 100644
--- a/src/jq/codegen.zig
+++ b/src/jq/codegen.zig
@@ -38,6 +38,22 @@ pub const Opcode = enum {
     store,
     append,
     each,
+
+    pub fn name(self: Opcode) []const u8 {
+        switch (self) {
+            inline else => |tag| {
+                const tag_name = @tagName(tag);
+                const upper_tag_name = comptime blk: {
+                    var buf: [tag_name.len]u8 = undefined;
+                    for (tag_name, 0..) |c, i| {
+                        buf[i] = std.ascii.toUpper(c);
+                    }
+                    break :blk buf;
+                };
+                return &upper_tag_name;
+            },
+        }
+    }
 };
 
 pub const Instr = union(Opcode) {
@@ -304,3 +320,26 @@ pub fn codegen(allocator: std.mem.Allocator, ast: *const Ast) ![]Instr {
     try gen.emit(.ret);
     return gen.toOwnedSlice();
 }
+
+pub fn disasm(allocator: std.mem.Allocator, instrs: []const Instr, constants: []const jv.Value, writer: *std.Io.Writer) !void {
+    for (instrs, 0..) |instr, i| {
+        try writer.print("{d:0>4} ", .{i});
+        try writer.writeAll(instr.op().name());
+        switch (instr) {
+            // program address
+            .jump, .jump_unless, .fork => |offset| try writer.print(" {d:0>4}", .{i + offset}),
+            // constant index
+            .@"const" => |idx| {
+                try writer.writeAll(" ");
+                const k = try jv.stringify(allocator, constants[@intFromEnum(idx)]);
+                defer allocator.free(k);
+                try writer.writeAll(k);
+            },
+            // variable index
+            .load, .store, .append => |idx| try writer.print(" ${d}", .{@intFromEnum(idx)}),
+            // no arguments
+            else => {},
+        }
+        try writer.writeAll("\n");
+    }
+}
diff --git a/src/jq/execute.zig b/src/jq/execute.zig
index d8081e6..cee7845 100644
--- a/src/jq/execute.zig
+++ b/src/jq/execute.zig
@@ -4,6 +4,7 @@ const tokenize = @import("./tokenize.zig").tokenize;
 const parse = @import("./parse.zig").parse;
 const Instr = @import("./codegen.zig").Instr;
 const codegen = @import("./codegen.zig").codegen;
+const disasm = @import("./codegen.zig").disasm;
 
 pub const ExecuteError = error{
     Unimplemented,
@@ -189,11 +190,6 @@ pub const Runtime = struct {
         const ast = try parse(self.allocator, compile_allocator.allocator(), tokens, &self.constants);
         const instrs = try codegen(self.allocator, ast);
         self.instrs = instrs;
-        // std.debug.print("BEGIN\n", .{});
-        // for (self.instrs) |instr| {
-        //     std.debug.print("{}\n", .{instr});
-        // }
-        // std.debug.print("END\n", .{});
     }
 
     pub fn compileFromSlice(self: *Self, query: []const u8) !void {
@@ -201,6 +197,10 @@ pub const Runtime = struct {
         return self.compileFromReader(&reader);
     }
 
+    pub fn dumpDisasm(self: *const Self, writer: *std.Io.Writer) !void {
+        try disasm(self.allocator, self.instrs, self.constants.items, writer);
+    }
+
     pub fn start(self: *Self, input: jv.Value) !void {
         try self.values.push(input.clone());
     }