Commit cd8070f94f

@@ -3372,7 +3372,7 @@ fn genArgDbgInfo(self: *Self, inst: Air.Inst.Index, arg_index: u32, stack_byte_c
 
     const mcv = self.args[arg_index];
     const ty = self.air.instructions.items(.data)[inst].ty;
-    const name = self.mod_fn.getParamName(arg_index);
+    const name = self.mod_fn.getParamName(self.bin_file.options.module.?, arg_index);
     const name_with_null = name.ptr[0 .. name.len + 1];
 
     switch (mcv) {

@@ -1619,7 +1619,7 @@ fn airFieldParentPtr(self: *Self, inst: Air.Inst.Index) !void {
 
 fn genArgDbgInfo(self: *Self, inst: Air.Inst.Index, mcv: MCValue, arg_index: u32) !void {
     const ty = self.air.instructions.items(.data)[inst].ty;
-    const name = self.mod_fn.getParamName(arg_index);
+    const name = self.mod_fn.getParamName(self.bin_file.options.module.?, arg_index);
     const name_with_null = name.ptr[0 .. name.len + 1];
 
     switch (mcv) {

@@ -2959,7 +2959,7 @@ fn finishAir(self: *Self, inst: Air.Inst.Index, result: MCValue, operands: [Live
 
 fn genArgDbgInfo(self: *Self, inst: Air.Inst.Index, mcv: MCValue, arg_index: u32) !void {
     const ty = self.air.instructions.items(.data)[inst].ty;
-    const name = self.mod_fn.getParamName(arg_index);
+    const name = self.mod_fn.getParamName(self.bin_file.options.module.?, arg_index);
     const name_with_null = name.ptr[0 .. name.len + 1];
 
     switch (mcv) {

@@ -1991,7 +1991,7 @@ fn airArg(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
     switch (self.debug_output) {
         .dwarf => |dwarf| {
             // TODO: Get the original arg index rather than wasm arg index
-            const name = self.mod_fn.getParamName(arg_index);
+            const name = self.mod_fn.getParamName(self.bin_file.base.options.module.?, arg_index);
             const leb_size = link.File.Wasm.getULEB128Size(arg.local);
             const dbg_info = &dwarf.dbg_info;
             try dbg_info.ensureUnusedCapacity(3 + leb_size + 5 + name.len + 1);

@@ -3789,7 +3789,7 @@ fn airArg(self: *Self, inst: Air.Inst.Index) !void {
 
     const ty = self.air.typeOfIndex(inst);
     const mcv = self.args[arg_index];
-    const name = self.mod_fn.getParamName(arg_index);
+    const name = self.mod_fn.getParamName(self.bin_file.options.module.?, arg_index);
     const name_with_null = name.ptr[0 .. name.len + 1];
 
     if (self.liveness.isUnused(inst))

@@ -7313,7 +7313,7 @@ pub const FuncGen = struct {
             const lbrace_col = func.lbrace_column + 1;
             const di_local_var = dib.createParameterVariable(
                 self.di_scope.?,
-                func.getParamName(src_index).ptr, // TODO test 0 bit args
+                func.getParamName(self.dg.module, src_index).ptr, // TODO test 0 bit args
                 self.di_file.?,
                 lbrace_line,
                 try self.dg.object.lowerDebugType(inst_ty, .full),

@@ -1471,14 +1471,6 @@ pub const Fn = struct {
     /// TODO apply the same enhancement for param_names below to this field.
     anytype_args: [*]bool,
 
-    /// Prefer to use `getParamName` to access this because of the future improvement
-    /// we want to do mentioned in the TODO below.
-    /// Stored in gpa.
-    /// TODO: change param ZIR instructions to be embedded inside the function
-    /// ZIR instruction instead of before it, so that `zir_body_inst` can be used to
-    /// determine param names rather than redundantly storing them here.
-    param_names: []const [:0]const u8,
-
     /// Precomputed hash for monomorphed_funcs.
     /// This is important because it may be accessed when resizing monomorphed_funcs
     /// while this Fn has already been added to the set, but does not have the
@@ -1590,18 +1582,28 @@ pub const Fn = struct {
             gpa.destroy(node);
             it = next;
         }
-
-        for (func.param_names) |param_name| {
-            gpa.free(param_name);
-        }
-        gpa.free(func.param_names);
     }
 
-    pub fn getParamName(func: Fn, index: u32) [:0]const u8 {
-        // TODO rework ZIR of parameters so that this function looks up
-        // param names in ZIR instead of redundantly saving them into Fn.
-        // const zir = func.owner_decl.getFileScope().zir;
-        return func.param_names[index];
+    pub fn getParamName(func: Fn, mod: *Module, index: u32) [:0]const u8 {
+        const file = mod.declPtr(func.owner_decl).getFileScope();
+
+        const tags = file.zir.instructions.items(.tag);
+        const data = file.zir.instructions.items(.data);
+
+        const param_body = file.zir.getParamBody(func.zir_body_inst);
+        const param = param_body[index];
+
+        return switch (tags[param]) {
+            .param, .param_comptime => blk: {
+                const extra = file.zir.extraData(Zir.Inst.Param, data[param].pl_tok.payload_index);
+                break :blk file.zir.nullTerminatedString(extra.data.name);
+            },
+            .param_anytype, .param_anytype_comptime => blk: {
+                const param_data = data[param].str_tok;
+                break :blk param_data.get(file.zir);
+            },
+            else => unreachable,
+        };
     }
 
     pub fn hasInferredErrorSet(func: Fn, mod: *Module) bool {

@@ -7753,11 +7753,6 @@ fn funcCommon(
         break :blk if (sema.comptime_args.len == 0) null else sema.comptime_args.ptr;
     } else null;
 
-    const param_names = try sema.gpa.alloc([:0]const u8, block.params.items.len);
-    for (param_names) |*param_name, i| {
-        param_name.* = try sema.gpa.dupeZ(u8, block.params.items[i].name);
-    }
-
     const hash = new_func.hash;
     const fn_payload = try sema.arena.create(Value.Payload.Function);
     new_func.* = .{
@@ -7771,7 +7766,6 @@ fn funcCommon(
         .rbrace_line = src_locs.rbrace_line,
         .lbrace_column = @truncate(u16, src_locs.columns),
         .rbrace_column = @truncate(u16, src_locs.columns >> 16),
-        .param_names = param_names,
         .branch_quota = default_branch_quota,
         .is_noinline = is_noinline,
     };

@@ -3909,6 +3909,27 @@ pub const FnInfo = struct {
     total_params_len: u32,
 };
 
+pub fn getParamBody(zir: Zir, fn_inst: Inst.Index) []const u32 {
+    const tags = zir.instructions.items(.tag);
+    const datas = zir.instructions.items(.data);
+    const inst_data = datas[fn_inst].pl_node;
+
+    const param_block_index = switch (tags[fn_inst]) {
+        .func, .func_inferred => blk: {
+            const extra = zir.extraData(Inst.Func, inst_data.payload_index);
+            break :blk extra.data.param_block;
+        },
+        .func_fancy => blk: {
+            const extra = zir.extraData(Inst.FuncFancy, inst_data.payload_index);
+            break :blk extra.data.param_block;
+        },
+        else => unreachable,
+    };
+
+    const param_block = zir.extraData(Inst.Block, datas[param_block_index].pl_node.payload_index);
+    return zir.extra[param_block.end..][0..param_block.data.body_len];
+}
+
 pub fn getFnInfo(zir: Zir, fn_inst: Inst.Index) FnInfo {
     const tags = zir.instructions.items(.tag);
     const datas = zir.instructions.items(.data);