add support for resolving parameters in function body

examples/hello.ry

@@ -42,8 +42,8 @@ fn multwo(num: i32, double_flag: bool) i32 {
     }
 }
 
-fn multwo_with_one(b: i32) i32 {
-    return multwo(b, false) + b;
+fn func_refer_param(b: i32) i32 {
+    return b * 231 + b;
 }
 
 fn add(a: i32, b: i32) i32 {

src/ast_printer.zig

@@ -401,7 +401,7 @@ pub fn printContext(ctx: CompilationContext) void {
                     std.debug.warn(
                         "\tparameter {} typ {}\n",
                         param_kv.key,
-                        prettyType(param_kv.value),
+                        prettyType(param_kv.value.typ),
                     );
                 }
 

src/codegen.zig

@@ -31,6 +31,8 @@ pub const Codegen = struct {
     ctx: *comp.CompilationContext,
     llvm_table: LLVMTable,
 
+    current_function_name: ?[]const u8 = null,
+
     pub fn init(allocator: *std.mem.Allocator, ctx: *comp.CompilationContext) Codegen {
         return Codegen{
             .allocator = allocator,
@@ -218,7 +220,32 @@ pub const Codegen = struct {
                 return llvm.LLVMBuildStore(builder, null, assign_expr);
             },
 
-            .Variable => @panic("TODO emit variables"),
+            .Variable => |vari| {
+                var kv_opt = self.ctx.metadata_map.get(expr);
+
+                if (kv_opt == null) {
+                    std.debug.warn("variable {} not fully analyzed\n", vari);
+                    return CompileError.EmitError;
+                }
+
+                // we have metadata, which means we can check if the variable
+                // is coming from the scope or from the function
+
+                var metadata = kv_opt.?.value;
+
+                return switch (metadata.using) {
+                    .Function => blk: {
+                        var param = metadata.from_function.?.parameters.get(vari.lexeme).?.value;
+                        var llvm_func = self.llvm_table.get(self.current_function_name.?).?.value;
+
+                        // may i thank all the demons in hell for giving me
+                        // good energies to make this work
+                        break :blk llvm.LLVMGetParam(llvm_func, @intCast(c_uint, param.idx));
+                    },
+
+                    .Scope => @panic("TODO local variables"),
+                };
+            },
 
             else => {
                 std.debug.warn("Got unexpected expr {}\n", ast.ExprType(expr.*));
@@ -333,6 +360,7 @@ pub const Codegen = struct {
             .Root => @panic("Should not have gotten Root"),
             .FnDecl => |decl| {
                 const name = decl.func_name.lexeme;
+                self.current_function_name = name;
 
                 var fn_sym_search = self.ctx.symbol_table.get(name).?.value;
                 std.debug.assert(comp.SymbolType(fn_sym_search) == .Function);
@@ -347,7 +375,7 @@ pub const Codegen = struct {
                 for (decl.params.toSlice()) |param| {
                     try param_types.append(try self.typeToLLVM(fn_sym.parameters.get(
                         param.name.lexeme,
-                    ).?.value));
+                    ).?.value.typ));
                 }
 
                 var llvm_ret_type = llvm.LLVMFunctionType(
@@ -372,13 +400,6 @@ pub const Codegen = struct {
                     try self.emitStmt(builder, &stmt);
                 }
 
-                //var tmp = llvm.LLVMBuildAdd(
-                //    builder,
-                //    llvm.LLVMGetParam(func, 0),
-                //    llvm.LLVMGetParam(func, 1),
-                //    c"tmp",
-                //);
-
                 std.debug.warn("cgen: generated function '{}'\n", name);
             },
 

src/comp_ctx.zig

@@ -69,6 +69,13 @@ pub const Scope = struct {
     }
 };
 
+pub const Parameter = struct {
+    idx: usize,
+    typ: SymbolUnderlyingType,
+};
+
+pub const ParameterMap = std.StringHashMap(Parameter);
+
 // functions, for our purposes, other than symbols, have:
 //  - a return type
 //  - parameters
@@ -78,24 +85,10 @@ pub const FunctionSymbol = struct {
 
     /// Parameters for a function are also a table instead of an ArrayList
     /// because we want to resolve identifiers to them.
-    parameters: UnderlyingTypeMap,
+    parameters: ParameterMap,
     parameter_list: TypeList,
 
     scope: *Scope,
-
-    /// Find a given identifier in the function. Can resolve to either a parameter
-    pub fn findSymbol(self: *const @This(), identifier: []const u8) ?SymbolData {
-        // try to find it on overall variable symbols
-
-        // TODO
-
-        //var var_sym = self.symbols.get(identifier);
-        //if (var_sym != null) return var_sym.?.value;
-
-        //var param_sym = self.parameters.get(identifier);
-        //if (param_sym != null) return param_sym.?.value;
-        return null;
-    }
 };
 
 // structs are hashmaps pointing to SymbolUnderlyingType
@@ -264,10 +257,13 @@ pub const CompilationContext = struct {
         param_types: TypeList,
         scope: *Scope,
     ) !void {
-        var type_map = UnderlyingTypeMap.init(self.allocator);
+        var param_map = ParameterMap.init(self.allocator);
 
         for (decl.params.toSlice()) |param, idx| {
-            _ = try type_map.put(param.name.lexeme, param_types.at(idx));
+            _ = try param_map.put(param.name.lexeme, Parameter{
+                .idx = idx,
+                .typ = param_types.at(idx),
+            });
         }
 
         const lex = decl.func_name.lexeme;
@@ -276,7 +272,7 @@ pub const CompilationContext = struct {
             .Function = FunctionSymbol{
                 .decl = decl,
                 .return_type = ret_type,
-                .parameters = type_map,
+                .parameters = param_map,
                 .parameter_list = param_types,
                 .scope = scope,
             },
@@ -353,7 +349,7 @@ pub const CompilationContext = struct {
 
         if (self.cur_function) |cur_function| {
             var kv_opt = cur_function.parameters.get(name);
-            if (kv_opt) |kv| return VariableMetadata.withParam(cur_function, kv.value);
+            if (kv_opt) |kv| return VariableMetadata.withParam(cur_function, kv.value.typ);
         }
 
         std.debug.warn("Unknown name {}\n", name);