InternPool: make more use of `NullTerminatedString.Slice`

This should avoid the random pointer invalidation crashes.

Closes #18954

9 files changed, 70 insertions, 61 deletions

diff --git a/src/Sema.zig b/src/Sema.zig
index d0b0efcf19..874c83ae0c 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -12619,8 +12619,9 @@ fn analyzeSwitchRuntimeBlock(
                         operand_ty.fmt(mod),
                     });
                 }
-                for (0..operand_ty.errorSetNames(mod).len) |i| {
-                    const error_name = operand_ty.errorSetNames(mod)[i];
+                const error_names = operand_ty.errorSetNames(mod);
+                for (0..error_names.len) |name_index| {
+                    const error_name = error_names.get(ip)[name_index];
                     if (seen_errors.contains(error_name)) continue;
                     cases_len += 1;
 
@@ -22362,8 +22363,9 @@ fn zirErrorCast(sema: *Sema, block: *Block, extended: Zir.Inst.Extended.InstData
         if (!operand_ty.isAnyError(mod) and operand_ty.errorSetIsEmpty(mod)) break :disjoint true;
         if (dest_ty.isAnyError(mod)) break :disjoint false;
         if (operand_ty.isAnyError(mod)) break :disjoint false;
-        for (dest_ty.errorSetNames(mod)) |dest_err_name| {
-            if (Type.errorSetHasFieldIp(ip, operand_ty.toIntern(), dest_err_name))
+        const dest_err_names = dest_ty.errorSetNames(mod);
+        for (0..dest_err_names.len) |dest_err_index| {
+            if (Type.errorSetHasFieldIp(ip, operand_ty.toIntern(), dest_err_names.get(ip)[dest_err_index]))
                 break :disjoint false;
         }
 
@@ -22375,8 +22377,8 @@ fn zirErrorCast(sema: *Sema, block: *Block, extended: Zir.Inst.Extended.InstData
 
         _ = try sema.resolveInferredErrorSetTy(block, src, dest_ty.toIntern());
         _ = try sema.resolveInferredErrorSetTy(block, operand_src, operand_ty.toIntern());
-        for (dest_ty.errorSetNames(mod)) |dest_err_name| {
-            if (Type.errorSetHasFieldIp(ip, operand_ty.toIntern(), dest_err_name))
+        for (0..dest_err_names.len) |dest_err_index| {
+            if (Type.errorSetHasFieldIp(ip, operand_ty.toIntern(), dest_err_names.get(ip)[dest_err_index]))
                 break :disjoint false;
         }
 
@@ -38780,17 +38782,18 @@ fn elemPtrType(sema: *Sema, ptr_ty: Type, offset: ?usize) !Type {
 /// Asserts that lhs and rhs are both error sets and are resolved.
 fn errorSetMerge(sema: *Sema, lhs: Type, rhs: Type) !Type {
     const mod = sema.mod;
+    const ip = &mod.intern_pool;
     const arena = sema.arena;
     const lhs_names = lhs.errorSetNames(mod);
     const rhs_names = rhs.errorSetNames(mod);
     var names: InferredErrorSet.NameMap = .{};
     try names.ensureUnusedCapacity(arena, lhs_names.len);
 
-    for (lhs_names) |name| {
-        names.putAssumeCapacityNoClobber(name, {});
+    for (0..lhs_names.len) |lhs_index| {
+        names.putAssumeCapacityNoClobber(lhs_names.get(ip)[lhs_index], {});
     }
-    for (rhs_names) |name| {
-        try names.put(arena, name, {});
+    for (0..rhs_names.len) |rhs_index| {
+        try names.put(arena, rhs_names.get(ip)[rhs_index], {});
     }
 
     return mod.errorSetFromUnsortedNames(names.keys());
diff --git a/src/arch/wasm/CodeGen.zig b/src/arch/wasm/CodeGen.zig
index 3ee36690e4..4540724778 100644
--- a/src/arch/wasm/CodeGen.zig
+++ b/src/arch/wasm/CodeGen.zig
@@ -7216,13 +7216,14 @@ fn airTagName(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
 
 fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
     const mod = func.bin_file.base.comp.module.?;
+    const ip = &mod.intern_pool;
     const enum_decl_index = enum_ty.getOwnerDecl(mod);
 
     var arena_allocator = std.heap.ArenaAllocator.init(func.gpa);
     defer arena_allocator.deinit();
     const arena = arena_allocator.allocator();
 
-    const fqn = mod.intern_pool.stringToSlice(try mod.declPtr(enum_decl_index).getFullyQualifiedName(mod));
+    const fqn = ip.stringToSlice(try mod.declPtr(enum_decl_index).getFullyQualifiedName(mod));
     const func_name = try std.fmt.allocPrintZ(arena, "__zig_tag_name_{s}", .{fqn});
 
     // check if we already generated code for this.
@@ -7252,9 +7253,9 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
 
     // TODO: Make switch implementation generic so we can use a jump table for this when the tags are not sparse.
     // generate an if-else chain for each tag value as well as constant.
-    for (enum_ty.enumFields(mod), 0..) |tag_name_ip, field_index_usize| {
-        const field_index = @as(u32, @intCast(field_index_usize));
-        const tag_name = mod.intern_pool.stringToSlice(tag_name_ip);
+    const tag_names = enum_ty.enumFields(mod);
+    for (0..tag_names.len) |tag_index| {
+        const tag_name = ip.stringToSlice(tag_names.get(ip)[tag_index]);
         // for each tag name, create an unnamed const,
         // and then get a pointer to its value.
         const name_ty = try mod.arrayType(.{
@@ -7279,7 +7280,7 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
         try writer.writeByte(std.wasm.opcode(.local_get));
         try leb.writeULEB128(writer, @as(u32, 1));
 
-        const tag_val = try mod.enumValueFieldIndex(enum_ty, field_index);
+        const tag_val = try mod.enumValueFieldIndex(enum_ty, @intCast(tag_index));
         const tag_value = try func.lowerConstant(tag_val, enum_ty);
 
         switch (tag_value) {
@@ -7372,6 +7373,7 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
 
 fn airErrorSetHasValue(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
     const mod = func.bin_file.base.comp.module.?;
+    const ip = &mod.intern_pool;
     const ty_op = func.air.instructions.items(.data)[@intFromEnum(inst)].ty_op;
 
     const operand = try func.resolveInst(ty_op.operand);
@@ -7384,8 +7386,8 @@ fn airErrorSetHasValue(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
 
     var lowest: ?u32 = null;
     var highest: ?u32 = null;
-    for (names) |name| {
-        const err_int = @as(Module.ErrorInt, @intCast(mod.global_error_set.getIndex(name).?));
+    for (0..names.len) |name_index| {
+        const err_int: Module.ErrorInt = @intCast(mod.global_error_set.getIndex(names.get(ip)[name_index]).?);
         if (lowest) |*l| {
             if (err_int < l.*) {
                 l.* = err_int;
diff --git a/src/arch/x86_64/CodeGen.zig b/src/arch/x86_64/CodeGen.zig
index 33b8623183..857b980aad 100644
--- a/src/arch/x86_64/CodeGen.zig
+++ b/src/arch/x86_64/CodeGen.zig
@@ -2187,6 +2187,7 @@ fn genBody(self: *Self, body: []const Air.Inst.Index) InnerError!void {
 
 fn genLazy(self: *Self, lazy_sym: link.File.LazySymbol) InnerError!void {
     const mod = self.bin_file.comp.module.?;
+    const ip = &mod.intern_pool;
     switch (lazy_sym.ty.zigTypeTag(mod)) {
         .Enum => {
             const enum_ty = lazy_sym.ty;
@@ -2209,10 +2210,10 @@ fn genLazy(self: *Self, lazy_sym: link.File.LazySymbol) InnerError!void {
             try self.genLazySymbolRef(.lea, data_reg, .{ .kind = .const_data, .ty = enum_ty });
 
             var data_off: i32 = 0;
-            for (exitlude_jump_relocs, 0..) |*exitlude_jump_reloc, index_usize| {
-                const index: u32 = @intCast(index_usize);
-                const tag_name = mod.intern_pool.stringToSlice(enum_ty.enumFields(mod)[index_usize]);
-                const tag_val = try mod.enumValueFieldIndex(enum_ty, index);
+            const tag_names = enum_ty.enumFields(mod);
+            for (exitlude_jump_relocs, 0..) |*exitlude_jump_reloc, tag_index| {
+                const tag_name_len = ip.stringToSlice(tag_names.get(ip)[tag_index]).len;
+                const tag_val = try mod.enumValueFieldIndex(enum_ty, @intCast(tag_index));
                 const tag_mcv = try self.genTypedValue(.{ .ty = enum_ty, .val = tag_val });
                 try self.genBinOpMir(.{ ._, .cmp }, enum_ty, enum_mcv, tag_mcv);
                 const skip_reloc = try self.asmJccReloc(.ne, undefined);
@@ -2228,14 +2229,14 @@ fn genLazy(self: *Self, lazy_sym: link.File.LazySymbol) InnerError!void {
                     .{ .reg = ret_reg },
                     8,
                     Type.usize,
-                    .{ .immediate = tag_name.len },
+                    .{ .immediate = tag_name_len },
                     .{},
                 );
 
                 exitlude_jump_reloc.* = try self.asmJmpReloc(undefined);
                 self.performReloc(skip_reloc);
 
-                data_off += @intCast(tag_name.len + 1);
+                data_off += @intCast(tag_name_len + 1);
             }
 
             try self.airTrap();
diff --git a/src/codegen.zig b/src/codegen.zig
index f16bf301a8..118bab4be9 100644
--- a/src/codegen.zig
+++ b/src/codegen.zig
@@ -119,6 +119,7 @@ pub fn generateLazySymbol(
 
     const comp = bin_file.comp;
     const zcu = comp.module.?;
+    const ip = &zcu.intern_pool;
     const target = comp.root_mod.resolved_target.result;
     const endian = target.cpu.arch.endian();
     const gpa = comp.gpa;
@@ -151,8 +152,9 @@ pub fn generateLazySymbol(
         return Result.ok;
     } else if (lazy_sym.ty.zigTypeTag(zcu) == .Enum) {
         alignment.* = .@"1";
-        for (lazy_sym.ty.enumFields(zcu)) |tag_name_ip| {
-            const tag_name = zcu.intern_pool.stringToSlice(tag_name_ip);
+        const tag_names = lazy_sym.ty.enumFields(zcu);
+        for (0..tag_names.len) |tag_index| {
+            const tag_name = zcu.intern_pool.stringToSlice(tag_names.get(ip)[tag_index]);
             try code.ensureUnusedCapacity(tag_name.len + 1);
             code.appendSliceAssumeCapacity(tag_name);
             code.appendAssumeCapacity(0);
diff --git a/src/codegen/c.zig b/src/codegen/c.zig
index 4adabea7bb..405d97bbd3 100644
--- a/src/codegen/c.zig
+++ b/src/codegen/c.zig
@@ -2595,6 +2595,7 @@ pub fn genGlobalAsm(mod: *Module, writer: anytype) !void {
 
 pub fn genErrDecls(o: *Object) !void {
     const mod = o.dg.module;
+    const ip = &mod.intern_pool;
     const writer = o.writer();
 
     var max_name_len: usize = 0;
@@ -2603,7 +2604,7 @@ pub fn genErrDecls(o: *Object) !void {
         try writer.writeAll("enum {\n");
         o.indent_writer.pushIndent();
         for (mod.global_error_set.keys()[1..], 1..) |name_nts, value| {
-            const name = mod.intern_pool.stringToSlice(name_nts);
+            const name = ip.stringToSlice(name_nts);
             max_name_len = @max(name.len, max_name_len);
             const err_val = try mod.intern(.{ .err = .{
                 .ty = .anyerror_type,
@@ -2621,8 +2622,8 @@ pub fn genErrDecls(o: *Object) !void {
     defer o.dg.gpa.free(name_buf);
 
     @memcpy(name_buf[0..name_prefix.len], name_prefix);
-    for (mod.global_error_set.keys()) |name_nts| {
-        const name = mod.intern_pool.stringToSlice(name_nts);
+    for (mod.global_error_set.keys()) |name_ip| {
+        const name = ip.stringToSlice(name_ip);
         @memcpy(name_buf[name_prefix.len..][0..name.len], name);
         const identifier = name_buf[0 .. name_prefix.len + name.len];
 
@@ -2652,7 +2653,7 @@ pub fn genErrDecls(o: *Object) !void {
     try o.dg.renderTypeAndName(writer, name_array_ty, .{ .identifier = array_identifier }, Const, .none, .complete);
     try writer.writeAll(" = {");
     for (mod.global_error_set.keys(), 0..) |name_nts, value| {
-        const name = mod.intern_pool.stringToSlice(name_nts);
+        const name = ip.stringToSlice(name_nts);
         if (value != 0) try writer.writeByte(',');
 
         const len_val = try mod.intValue(Type.usize, name.len);
@@ -2730,6 +2731,7 @@ fn genExports(o: *Object) !void {
 
 pub fn genLazyFn(o: *Object, lazy_fn: LazyFnMap.Entry) !void {
     const mod = o.dg.module;
+    const ip = &mod.intern_pool;
     const w = o.writer();
     const key = lazy_fn.key_ptr.*;
     const val = lazy_fn.value_ptr;
@@ -2747,23 +2749,23 @@ pub fn genLazyFn(o: *Object, lazy_fn: LazyFnMap.Entry) !void {
             try w.writeByte('(');
             try o.dg.renderTypeAndName(w, enum_ty, .{ .identifier = "tag" }, Const, .none, .complete);
             try w.writeAll(") {\n switch (tag) {\n");
-            for (enum_ty.enumFields(mod), 0..) |name_ip, index_usize| {
-                const index = @as(u32, @intCast(index_usize));
-                const name = mod.intern_pool.stringToSlice(name_ip);
-                const tag_val = try mod.enumValueFieldIndex(enum_ty, index);
+            const tag_names = enum_ty.enumFields(mod);
+            for (0..tag_names.len) |tag_index| {
+                const tag_name = ip.stringToSlice(tag_names.get(ip)[tag_index]);
+                const tag_val = try mod.enumValueFieldIndex(enum_ty, @intCast(tag_index));
 
                 const int_val = try tag_val.intFromEnum(enum_ty, mod);
 
                 const name_ty = try mod.arrayType(.{
-                    .len = name.len,
+                    .len = tag_name.len,
                     .child = .u8_type,
                     .sentinel = .zero_u8,
                 });
                 const name_val = try mod.intern(.{ .aggregate = .{
                     .ty = name_ty.toIntern(),
-                    .storage = .{ .bytes = name },
+                    .storage = .{ .bytes = tag_name },
                 } });
-                const len_val = try mod.intValue(Type.usize, name.len);
+                const len_val = try mod.intValue(Type.usize, tag_name.len);
 
                 try w.print("  case {}: {{\n   static ", .{
                     try o.dg.fmtIntLiteral(enum_ty, int_val, .Other),
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index f5b4aa540f..017abf8eaf 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -9574,6 +9574,7 @@ pub const FuncGen = struct {
     fn airErrorSetHasValue(self: *FuncGen, inst: Air.Inst.Index) !Builder.Value {
         const o = self.dg.object;
         const mod = o.module;
+        const ip = &mod.intern_pool;
         const ty_op = self.air.instructions.items(.data)[@intFromEnum(inst)].ty_op;
         const operand = try self.resolveInst(ty_op.operand);
         const error_set_ty = ty_op.ty.toType();
@@ -9585,8 +9586,8 @@ pub const FuncGen = struct {
         var wip_switch = try self.wip.@"switch"(operand, invalid_block, @intCast(names.len));
         defer wip_switch.finish(&self.wip);
 
-        for (names) |name| {
-            const err_int = mod.global_error_set.getIndex(name).?;
+        for (0..names.len) |name_index| {
+            const err_int = mod.global_error_set.getIndex(names.get(ip)[name_index]).?;
             const this_tag_int_value = try o.builder.intConst(try o.errorIntType(), err_int);
             try wip_switch.addCase(this_tag_int_value, valid_block, &self.wip);
         }
diff --git a/src/link/Dwarf.zig b/src/link/Dwarf.zig
index a5dd57a406..51a8e5aa61 100644
--- a/src/link/Dwarf.zig
+++ b/src/link/Dwarf.zig
@@ -2828,7 +2828,7 @@ fn addDbgInfoErrorSet(
     target: std.Target,
     dbg_info_buffer: *std.ArrayList(u8),
 ) !void {
-    return addDbgInfoErrorSetNames(mod, ty, ty.errorSetNames(mod), target, dbg_info_buffer);
+    return addDbgInfoErrorSetNames(mod, ty, ty.errorSetNames(mod).get(&mod.intern_pool), target, dbg_info_buffer);
 }
 
 fn addDbgInfoErrorSetNames(
diff --git a/src/type.zig b/src/type.zig
index 43eaa9132a..a6265692c2 100644
--- a/src/type.zig
+++ b/src/type.zig
@@ -2908,22 +2908,21 @@ pub const Type = struct {
 
     // Asserts that `ty` is an error set and not `anyerror`.
     // Asserts that `ty` is resolved if it is an inferred error set.
-    pub fn errorSetNames(ty: Type, mod: *Module) []const InternPool.NullTerminatedString {
+    pub fn errorSetNames(ty: Type, mod: *Module) InternPool.NullTerminatedString.Slice {
         const ip = &mod.intern_pool;
         return switch (ip.indexToKey(ty.toIntern())) {
-            .error_set_type => |x| x.names.get(ip),
+            .error_set_type => |x| x.names,
             .inferred_error_set_type => |i| switch (ip.funcIesResolved(i).*) {
                 .none => unreachable, // unresolved inferred error set
                 .anyerror_type => unreachable,
-                else => |t| ip.indexToKey(t).error_set_type.names.get(ip),
+                else => |t| ip.indexToKey(t).error_set_type.names,
             },
             else => unreachable,
         };
     }
 
-    pub fn enumFields(ty: Type, mod: *Module) []const InternPool.NullTerminatedString {
-        const ip = &mod.intern_pool;
-        return ip.indexToKey(ty.toIntern()).enum_type.names.get(ip);
+    pub fn enumFields(ty: Type, mod: *Module) InternPool.NullTerminatedString.Slice {
+        return mod.intern_pool.indexToKey(ty.toIntern()).enum_type.names;
     }
 
     pub fn enumFieldCount(ty: Type, mod: *Module) usize {
diff --git a/test/cbe.zig b/test/cbe.zig
index 99a62c0ad5..35c2d8e8f9 100644
--- a/test/cbe.zig
+++ b/test/cbe.zig
@@ -219,23 +219,22 @@ pub fn addCases(ctx: *Cases, b: *std.Build) !void {
         , "");
     }
 
-    // https://github.com/ziglang/zig/issues/18954
-    //{
-    //    var case = ctx.exeFromCompiledC("inferred local const and var", .{}, b);
+    {
+        var case = ctx.exeFromCompiledC("inferred local const and var", .{}, b);
 
-    //    case.addCompareOutput(
-    //        \\fn add(a: i32, b: i32) i32 {
-    //        \\    return a + b;
-    //        \\}
-    //        \\
-    //        \\pub export fn main() c_int {
-    //        \\    const x = add(1, 2);
-    //        \\    var y = add(3, 0);
-    //        \\    y -= x;
-    //        \\    return y;
-    //        \\}
-    //    , "");
-    //}
+        case.addCompareOutput(
+            \\fn add(a: i32, b: i32) i32 {
+            \\    return a + b;
+            \\}
+            \\
+            \\pub export fn main() c_int {
+            \\    const x = add(1, 2);
+            \\    var y = add(3, 0);
+            \\    y -= x;
+            \\    return y;
+            \\}
+        , "");
+    }
     {
         var case = ctx.exeFromCompiledC("control flow", .{}, b);