ability to inline at function callsite

closes #306

Author: andrewrk

doc/langref.md

@@ -81,9 +81,9 @@ SwitchProng = (list(SwitchItem, ",") | "else") "=>" option("|" option("*") Symbo
 
 SwitchItem = Expression | (Expression "..." Expression)
 
-WhileExpression(body) = option("inline") "while" "(" Expression option(";" Expression) ")" body
+WhileExpression(body) = "while" "(" Expression option(";" Expression) ")" body
 
-ForExpression(body) = option("inline") "for" "(" Expression ")" option("|" option("*") Symbol option("," Symbol) "|") body
+ForExpression(body) = "for" "(" Expression ")" option("|" option("*") Symbol option("," Symbol) "|") body
 
 BoolOrExpression = BoolAndExpression "or" BoolOrExpression | BoolAndExpression
 
@@ -127,7 +127,9 @@ MultiplyOperator = "*" | "/" | "%" | "**" | "*%"
 
 PrefixOpExpression = PrefixOp PrefixOpExpression | SuffixOpExpression
 
-SuffixOpExpression = PrimaryExpression option(FnCallExpression | ArrayAccessExpression | FieldAccessExpression | SliceExpression)
+SuffixOpExpression = InlineExpression option(FnCallExpression | ArrayAccessExpression | FieldAccessExpression | SliceExpression)
+
+InlineExpression = option("inline") PrimaryExpression
 
 FieldAccessExpression = "." Symbol
 
@@ -161,6 +163,7 @@ ContainerDecl = option("extern" | "packed") ("struct" | "enum" | "union") "{" ma
 ## Operator Precedence
 
 ```
+inline x
 x() x[] x.y
 !x -x -%x ~x *x &x ?x %x %%x ??x
 x{}

src/all_types.hpp

@@ -167,6 +167,7 @@ struct ConstErrValue {
 struct ConstBoundFnValue {
     FnTableEntry *fn;
     IrInstruction *first_arg;
+    bool is_inline;
 };
 
 struct ConstArgTuple {
@@ -192,6 +193,11 @@ enum RuntimeHintMaybe {
     RuntimeHintMaybeNonNull,
 };
 
+struct ConstFn {
+    FnTableEntry *fn_entry;
+    bool is_inline;
+};
+
 struct ConstExprValue {
     TypeTableEntry *type;
     ConstValSpecial special;
@@ -202,7 +208,7 @@ struct ConstExprValue {
         // populated if special == ConstValSpecialStatic
         BigNum x_bignum;
         bool x_bool;
-        FnTableEntry *x_fn;
+        ConstFn x_fn;
         ConstBoundFnValue x_bound_fn;
         TypeTableEntry *x_type;
         ConstExprValue *x_maybe;
@@ -366,6 +372,7 @@ enum NodeType {
     NodeTypeTypeLiteral,
     NodeTypeVarLiteral,
     NodeTypeTryExpr,
+    NodeTypeInlineExpr,
 };
 
 struct AstNodeRoot {
@@ -789,6 +796,10 @@ struct AstNodeTypeLiteral {
 struct AstNodeVarLiteral {
 };
 
+struct AstNodeInlineExpr {
+    AstNode *body;
+};
+
 struct AstNode {
     enum NodeType type;
     size_t line;
@@ -847,6 +858,7 @@ struct AstNode {
         AstNodeErrorType error_type;
         AstNodeTypeLiteral type_literal;
         AstNodeVarLiteral var_literal;
+        AstNodeInlineExpr inline_expr;
     } data;
 };
 
@@ -1748,6 +1760,7 @@ enum IrInstructionId {
     IrInstructionIdDeclRef,
     IrInstructionIdPanic,
     IrInstructionIdEnumTagName,
+    IrInstructionIdSetFnRefInline,
 };
 
 struct IrInstruction {
@@ -1943,6 +1956,7 @@ struct IrInstructionCall {
     IrInstruction **args;
     bool is_comptime;
     LLVMValueRef tmp_ptr;
+    bool is_inline;
 };
 
 struct IrInstructionConst {
@@ -2493,6 +2507,12 @@ struct IrInstructionEnumTagName {
     IrInstruction *target;
 };
 
+struct IrInstructionSetFnRefInline {
+    IrInstruction base;
+
+    IrInstruction *fn_ref;
+};
+
 static const size_t slice_ptr_index = 0;
 static const size_t slice_len_index = 1;
 

src/analyze.cpp

@@ -2129,6 +2129,7 @@ void scan_decls(CodeGen *g, ScopeDecls *decls_scope, AstNode *node) {
         case NodeTypeTypeLiteral:
         case NodeTypeVarLiteral:
         case NodeTypeTryExpr:
+        case NodeTypeInlineExpr:
             zig_unreachable();
     }
 }
@@ -3251,7 +3252,8 @@ static uint32_t hash_const_val(ConstExprValue *const_val) {
             // TODO better hashing algorithm
             return 31643936;
         case TypeTableEntryIdFn:
-            return hash_ptr(const_val->data.x_fn);
+            return hash_ptr(const_val->data.x_fn.fn_entry) +
+                (const_val->data.x_fn.is_inline ? 4133894920 : 3983484790);
         case TypeTableEntryIdTypeDecl:
             return hash_ptr(const_val->data.x_type);
         case TypeTableEntryIdNamespace:
@@ -3697,7 +3699,8 @@ bool const_values_equal(ConstExprValue *a, ConstExprValue *b) {
         case TypeTableEntryIdPureError:
             return a->data.x_pure_err == b->data.x_pure_err;
         case TypeTableEntryIdFn:
-            return a->data.x_fn == b->data.x_fn;
+            return a->data.x_fn.fn_entry == b->data.x_fn.fn_entry &&
+                a->data.x_fn.is_inline == b->data.x_fn.is_inline;
         case TypeTableEntryIdBool:
             return a->data.x_bool == b->data.x_bool;
         case TypeTableEntryIdInt:
@@ -3933,8 +3936,9 @@ void render_const_value(Buf *buf, ConstExprValue *const_val) {
             zig_unreachable();
         case TypeTableEntryIdFn:
             {
-                FnTableEntry *fn_entry = const_val->data.x_fn;
-                buf_appendf(buf, "%s", buf_ptr(&fn_entry->symbol_name));
+                FnTableEntry *fn_entry = const_val->data.x_fn.fn_entry;
+                const char *inline_str = const_val->data.x_fn.is_inline ? "inline " : "";
+                buf_appendf(buf, "%s%s", inline_str, buf_ptr(&fn_entry->symbol_name));
                 return;
             }
         case TypeTableEntryIdBlock:
@@ -4011,7 +4015,8 @@ void render_const_value(Buf *buf, ConstExprValue *const_val) {
         case TypeTableEntryIdBoundFn:
             {
                 FnTableEntry *fn_entry = const_val->data.x_bound_fn.fn;
-                buf_appendf(buf, "(bound fn %s)", buf_ptr(&fn_entry->symbol_name));
+                const char *inline_str = const_val->data.x_bound_fn.is_inline ? "inline " : "";
+                buf_appendf(buf, "(%sbound fn %s)", inline_str, buf_ptr(&fn_entry->symbol_name));
                 return;
             }
         case TypeTableEntryIdStruct:

src/ast_render.cpp

@@ -240,6 +240,8 @@ static const char *node_type_str(NodeType node_type) {
             return "VarLiteral";
         case NodeTypeTryExpr:
             return "TryExpr";
+        case NodeTypeInlineExpr:
+            return "InlineExpr";
     }
     zig_unreachable();
 }
@@ -921,6 +923,12 @@ static void render_node_extra(AstRender *ar, AstNode *node, bool grouped) {
                 render_node_ungrouped(ar, node->data.unwrap_err_expr.op2);
                 break;
             }
+        case NodeTypeInlineExpr:
+            {
+                fprintf(ar->f, "inline ");
+                render_node_grouped(ar, node->data.inline_expr.body);
+                break;
+            }
         case NodeTypeFnDecl:
         case NodeTypeParamDecl:
         case NodeTypeErrorValueDecl:

src/codegen.cpp

@@ -608,7 +608,7 @@ static void gen_panic(CodeGen *g, LLVMValueRef msg_arg) {
         LLVMBuildLoad(g->builder, ptr_ptr, ""),
         LLVMBuildLoad(g->builder, len_ptr, ""),
     };
-    ZigLLVMBuildCall(g->builder, fn_val, args, 2, panic_fn->type_entry->data.fn.calling_convention, "");
+    ZigLLVMBuildCall(g->builder, fn_val, args, 2, panic_fn->type_entry->data.fn.calling_convention, false, "");
     LLVMBuildUnreachable(g->builder);
 }
 
@@ -1773,8 +1773,12 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutable *executable, IrInstr
         }
     }
 
+    bool want_always_inline = (instruction->fn_entry != nullptr &&
+            instruction->fn_entry->fn_inline == FnInlineAlways) || instruction->is_inline;
+
     LLVMValueRef result = ZigLLVMBuildCall(g->builder, fn_val,
-            gen_param_values, (unsigned)gen_param_index, fn_type->data.fn.calling_convention, "");
+            gen_param_values, (unsigned)gen_param_index, fn_type->data.fn.calling_convention,
+            want_always_inline, "");
 
     for (size_t param_i = 0; param_i < fn_type_id->param_count; param_i += 1) {
         FnGenParamInfo *gen_info = &fn_type->data.fn.gen_param_info[param_i];
@@ -2749,6 +2753,7 @@ static LLVMValueRef ir_render_instruction(CodeGen *g, IrExecutable *executable,
         case IrInstructionIdSetGlobalLinkage:
         case IrInstructionIdDeclRef:
         case IrInstructionIdSwitchVar:
+        case IrInstructionIdSetFnRefInline:
             zig_unreachable();
         case IrInstructionIdReturn:
             return ir_render_return(g, executable, (IrInstructionReturn *)instruction);
@@ -3183,7 +3188,7 @@ static LLVMValueRef gen_const_val(CodeGen *g, ConstExprValue *const_val) {
                 }
             }
         case TypeTableEntryIdFn:
-            return fn_llvm_value(g, const_val->data.x_fn);
+            return fn_llvm_value(g, const_val->data.x_fn.fn_entry);
         case TypeTableEntryIdPointer:
             {
                 render_const_val_global(g, const_val, "");