Merge pull request #8636 from jmc-88/issue-3779

Change builtins to return a string literal

Author: Vexu

doc/langref.html.in

@@ -2986,7 +2986,7 @@ test "@typeInfo" {
     try expect(mem.eql(u8, @typeInfo(Small).Enum.fields[1].name, "two"));
 }
 
-// @tagName gives a []const u8 representation of an enum value:
+// @tagName gives a [:0]const u8 representation of an enum value:
 test "@tagName" {
     try expect(mem.eql(u8, @tagName(Small.three), "three"));
 }
@@ -3233,7 +3233,7 @@ test "union method" {
       {#code_end#}
       <p>
       {#link|@tagName#} can be used to return a {#link|comptime#}
-      {#syntax#}[]const u8{#endsyntax#} value representing the field name:
+      {#syntax#}[:0]const u8{#endsyntax#} value representing the field name:
       </p>
       {#code_begin|test#}
 const std = @import("std");
@@ -7447,7 +7447,7 @@ test "main" {
       {#see_also|@divFloor|@divExact#}
       {#header_close#}
       {#header_open|@embedFile#}
-      <pre>{#syntax#}@embedFile(comptime path: []const u8) *const [X:0]u8{#endsyntax#}</pre>
+      <pre>{#syntax#}@embedFile(comptime path: []const u8) *const [N:0]u8{#endsyntax#}</pre>
       <p>
       This function returns a compile time constant pointer to null-terminated,
       fixed-size array with length equal to the byte count of the file given by
@@ -7475,7 +7475,7 @@ test "main" {
       {#header_close#}
 
       {#header_open|@errorName#}
-      <pre>{#syntax#}@errorName(err: anyerror) []const u8{#endsyntax#}</pre>
+      <pre>{#syntax#}@errorName(err: anyerror) [:0]const u8{#endsyntax#}</pre>
       <p>
       This function returns the string representation of an error. The string representation
       of {#syntax#}error.OutOfMem{#endsyntax#} is {#syntax#}"OutOfMem"{#endsyntax#}.
@@ -8494,9 +8494,9 @@ fn doTheTest() !void {
       {#header_close#}
 
       {#header_open|@tagName#}
-      <pre>{#syntax#}@tagName(value: anytype) []const u8{#endsyntax#}</pre>
+      <pre>{#syntax#}@tagName(value: anytype) [:0]const u8{#endsyntax#}</pre>
       <p>
-      Converts an enum value or union value to a slice of bytes representing the name.</p><p>If the enum is non-exhaustive and the tag value does not map to a name, it invokes safety-checked {#link|Undefined Behavior#}.
+      Converts an enum value or union value to a string literal representing the name.</p><p>If the enum is non-exhaustive and the tag value does not map to a name, it invokes safety-checked {#link|Undefined Behavior#}.
       </p>
       {#header_close#}
 
@@ -8623,7 +8623,7 @@ test "integer truncation" {
       {#header_close#}
 
       {#header_open|@typeName#}
-      <pre>{#syntax#}@typeName(T: type) [N]u8{#endsyntax#}</pre>
+      <pre>{#syntax#}@typeName(T: type) *const [N:0]u8{#endsyntax#}</pre>
       <p>
       This function returns the string representation of a type, as
       an array. It is equivalent to a string literal of the type name.

src/stage1/analyze.cpp

@@ -6291,6 +6291,11 @@ ZigValue *create_const_str_lit(CodeGen *g, Buf *str) {
     return const_val;
 }
 
+ZigValue *create_sentineled_str_lit(CodeGen *g, Buf *str, ZigValue *sentinel) {
+    ZigValue *array_val = create_const_str_lit(g, str)->data.x_ptr.data.ref.pointee;
+    return create_const_slice(g, array_val, 0, buf_len(str), true, sentinel);
+}
+
 void init_const_bigint(ZigValue *const_val, ZigType *type, const BigInt *bigint) {
     const_val->special = ConstValSpecialStatic;
     const_val->type = type;
@@ -6444,12 +6449,12 @@ ZigValue *create_const_type(CodeGen *g, ZigType *type_value) {
 }
 
 void init_const_slice(CodeGen *g, ZigValue *const_val, ZigValue *array_val,
-        size_t start, size_t len, bool is_const)
+        size_t start, size_t len, bool is_const, ZigValue *sentinel)
 {
     assert(array_val->type->id == ZigTypeIdArray);
 
-    ZigType *ptr_type = get_pointer_to_type_extra(g, array_val->type->data.array.child_type,
-            is_const, false, PtrLenUnknown, 0, 0, 0, false);
+    ZigType *ptr_type = get_pointer_to_type_extra2(g, array_val->type->data.array.child_type,
+            is_const, false, PtrLenUnknown, 0, 0, 0, false, VECTOR_INDEX_NONE, nullptr, sentinel);
 
     const_val->special = ConstValSpecialStatic;
     const_val->type = get_slice_type(g, ptr_type);
@@ -6460,9 +6465,9 @@ void init_const_slice(CodeGen *g, ZigValue *const_val, ZigValue *array_val,
     init_const_usize(g, const_val->data.x_struct.fields[slice_len_index], len);
 }
 
-ZigValue *create_const_slice(CodeGen *g, ZigValue *array_val, size_t start, size_t len, bool is_const) {
+ZigValue *create_const_slice(CodeGen *g, ZigValue *array_val, size_t start, size_t len, bool is_const, ZigValue *sentinel) {
     ZigValue *const_val = g->pass1_arena->create<ZigValue>();
-    init_const_slice(g, const_val, array_val, start, len, is_const);
+    init_const_slice(g, const_val, array_val, start, len, is_const, sentinel);
     return const_val;
 }
 

src/stage1/analyze.hpp

@@ -144,6 +144,7 @@ ScopeExpr *create_expr_scope(CodeGen *g, AstNode *node, Scope *parent);
 
 void init_const_str_lit(CodeGen *g, ZigValue *const_val, Buf *str, bool move_str);
 ZigValue *create_const_str_lit(CodeGen *g, Buf *str);
+ZigValue *create_sentineled_str_lit(CodeGen *g, Buf *str, ZigValue *sentinel);
 
 void init_const_bigint(ZigValue *const_val, ZigType *type, const BigInt *bigint);
 ZigValue *create_const_bigint(CodeGen *g, ZigType *type, const BigInt *bigint);
@@ -186,8 +187,8 @@ ZigValue *create_const_ptr_array(CodeGen *g, ZigValue *array_val, size_t elem_in
         bool is_const, PtrLen ptr_len);
 
 void init_const_slice(CodeGen *g, ZigValue *const_val, ZigValue *array_val,
-        size_t start, size_t len, bool is_const);
-ZigValue *create_const_slice(CodeGen *g, ZigValue *array_val, size_t start, size_t len, bool is_const);
+        size_t start, size_t len, bool is_const, ZigValue *sentinel);
+ZigValue *create_const_slice(CodeGen *g, ZigValue *array_val, size_t start, size_t len, bool is_const, ZigValue *sentinel);
 
 void init_const_null(ZigValue *const_val, ZigType *type);
 ZigValue *create_const_null(CodeGen *g, ZigType *type);

src/stage1/codegen.cpp

@@ -1022,7 +1022,7 @@ static LLVMValueRef get_panic_msg_ptr_val(CodeGen *g, PanicMsgId msg_id) {
 
         Buf *buf_msg = panic_msg_buf(msg_id);
         ZigValue *array_val = create_const_str_lit(g, buf_msg)->data.x_ptr.data.ref.pointee;
-        init_const_slice(g, val, array_val, 0, buf_len(buf_msg), true);
+        init_const_slice(g, val, array_val, 0, buf_len(buf_msg), true, nullptr);
 
         render_const_val(g, val, "");
         render_const_val_global(g, val, "");
@@ -9428,7 +9428,7 @@ static void update_test_functions_builtin_decl(CodeGen *g) {
 
         ZigValue *name_field = this_val->data.x_struct.fields[0];
         ZigValue *name_array_val = create_const_str_lit(g, &test_fn_entry->symbol_name)->data.x_ptr.data.ref.pointee;
-        init_const_slice(g, name_field, name_array_val, 0, buf_len(&test_fn_entry->symbol_name), true);
+        init_const_slice(g, name_field, name_array_val, 0, buf_len(&test_fn_entry->symbol_name), true, nullptr);
 
         ZigValue *fn_field = this_val->data.x_struct.fields[1];
         fn_field->type = fn_type;
@@ -9452,7 +9452,7 @@ static void update_test_functions_builtin_decl(CodeGen *g) {
     }
     report_errors_and_maybe_exit(g);
 
-    ZigValue *test_fn_slice = create_const_slice(g, test_fn_array, 0, g->test_fns.length, true);
+    ZigValue *test_fn_slice = create_const_slice(g, test_fn_array, 0, g->test_fns.length, true, nullptr);
 
     update_compile_var(g, buf_create_from_str("test_functions"), test_fn_slice);
     assert(g->test_runner_package != nullptr);