Commit 4765294ca4bd7dd54207892b199f3053702d9a2a | zig

author	Jacob Young <jacobly@ziglang.org> 2022-10-19 07:56:02-04:00
committer	Jacob Young <jacobly@ziglang.org> 2022-10-25 05:11:29-04:00
log	4765294ca4bd7dd54207892b199f3053702d9a2a
tree	678317de9d228b5d4532805fd7457af240cc0110
parent	912b84bbad698d18a6b844f9c05c074d2880e35b

cbe: get enough things working to support basic programs

 * Enable advanced start support.
 * Enable advanced test_runner support.
 * Zig Language Reference's Hello World now works.

11 files changed, 321 insertions(+), 198 deletions(-)

lib
- include
  - zig.h
- std
  - debug.zig
  - os
    linux
    x86_64.zig
  - start.zig
- test_runner.zig
src
- codegen
  - c.zig
- main.zig
test
- behavior

lib/include/zig.h+6-1

 @@ -14,6 +14,12 @@
 #define zig_threadlocal zig_threadlocal_unavailable
 #endif
+#if defined(_MSC_VER)
+#define ZIG_NAKED __declspec(naked)
+#else
+#define ZIG_NAKED __attribute__((naked))
+#endif
 #if __GNUC__
 #define ZIG_COLD __attribute__ ((cold))
 #else
 @@ -165,7 +171,6 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <limits.h>
-#include <math.h>
 #define int128_t __int128
 #define uint128_t unsigned __int128

lib/std/debug.zig+7-1

 @@ -1222,7 +1222,13 @@ pub const DebugInfo = struct {
     }
     pub fn getModuleForAddress(self: *DebugInfo, address: usize) !*ModuleDebugInfo {
-        if (comptime builtin.target.isDarwin()) {
+        if (builtin.zig_backend == .stage2_c) {
+            return @as(error{
+                InvalidDebugInfo,
+                MissingDebugInfo,
+                UnsupportedBackend,
+            }, error.UnsupportedBackend);
+        } else if (comptime builtin.target.isDarwin()) {
             return self.lookupModuleDyld(address);
         } else if (native_os == .windows) {
             return self.lookupModuleWin32(address);

lib/std/os/linux/x86_64.zig+12-5

 @@ -108,11 +108,18 @@ pub extern fn clone(func: CloneFn, stack: usize, flags: usize, arg: usize, ptid:
 pub const restore = restore_rt;
 pub fn restore_rt() callconv(.Naked) void {
-    return asm volatile ("syscall"
+    switch (@import("builtin").zig_backend) {
-        :
+        .stage2_c => return asm volatile (std.fmt.comptimePrint(
-        : [number] "{rax}" (@enumToInt(SYS.rt_sigreturn)),
+                \\ movl ${d}, %%eax
-        : "rcx", "r11", "memory"
+                \\ syscall
-    );
+                \\ retq
+            , .{@enumToInt(SYS.rt_sigreturn)}) ::: "rcx", "r11", "memory"),
+        else => return asm volatile ("syscall"
+            :
+            : [number] "{rax}" (@enumToInt(SYS.rt_sigreturn)),
+            : "rcx", "r11", "memory"
+        ),
+    }
 }
 pub const mode_t = usize;

lib/std/start.zig+86-72

 @@ -23,7 +23,6 @@ comptime {
     // Until then, we have simplified logic here for self-hosted. TODO remove this once
     // self-hosted is capable enough to handle all of the real start.zig logic.
     if (builtin.zig_backend == .stage2_wasm or
-        builtin.zig_backend == .stage2_c or
         builtin.zig_backend == .stage2_x86_64 or
         builtin.zig_backend == .stage2_x86 or
         builtin.zig_backend == .stage2_aarch64 or
 @@ -265,75 +264,90 @@ fn EfiMain(handle: uefi.Handle, system_table: *uefi.tables.SystemTable) callconv
 }
 fn _start() callconv(.Naked) noreturn {
-    switch (native_arch) {
+    switch (builtin.zig_backend) {
-        .x86_64 => {
+        .stage2_c => switch (native_arch) {
-            argc_argv_ptr = asm volatile (
+            .x86_64 => {
-                \\ xor %%rbp, %%rbp
+                @export(argc_argv_ptr, .{ .name = "argc_argv_ptr" });
-                : [argc] "={rsp}" (-> [*]usize),
+                @export(posixCallMainAndExit, .{ .name = "_posixCallMainAndExit" });
-            );
+                asm volatile (
-        },
+                    \\ xor %%rbp, %%rbp
-        .i386 => {
+                    \\ mov %%rsp, argc_argv_ptr
-            argc_argv_ptr = asm volatile (
+                    \\ call _posixCallMainAndExit
-                \\ xor %%ebp, %%ebp
+                );
-                : [argc] "={esp}" (-> [*]usize),
+                unreachable;
-            );
+            },
-        },
+            else => @compileError("unsupported arch"),
-        .aarch64, .aarch64_be, .arm, .armeb, .thumb => {
-            argc_argv_ptr = asm volatile (
-                \\ mov fp, #0
-                \\ mov lr, #0
-                : [argc] "={sp}" (-> [*]usize),
-            );
-        },
-        .riscv64 => {
-            argc_argv_ptr = asm volatile (
-                \\ li s0, 0
-                \\ li ra, 0
-                : [argc] "={sp}" (-> [*]usize),
-            );
-        },
-        .mips, .mipsel => {
-            // The lr is already zeroed on entry, as specified by the ABI.
-            argc_argv_ptr = asm volatile (
-                \\ move $fp, $0
-                : [argc] "={sp}" (-> [*]usize),
-            );
-        },
-        .powerpc => {
-            // Setup the initial stack frame and clear the back chain pointer.
-            argc_argv_ptr = asm volatile (
-                \\ mr 4, 1
-                \\ li 0, 0
-                \\ stwu 1,-16(1)
-                \\ stw 0, 0(1)
-                \\ mtlr 0
-                : [argc] "={r4}" (-> [*]usize),
-                :
-                : "r0"
-            );
-        },
-        .powerpc64le => {
-            // Setup the initial stack frame and clear the back chain pointer.
-            // TODO: Support powerpc64 (big endian) on ELFv2.
-            argc_argv_ptr = asm volatile (
-                \\ mr 4, 1
-                \\ li 0, 0
-                \\ stdu 0, -32(1)
-                \\ mtlr 0
-                : [argc] "={r4}" (-> [*]usize),
-                :
-                : "r0"
-            );
         },
-        .sparc64 => {
+        else => switch (native_arch) {
-            // argc is stored after a register window (16 registers) plus stack bias
+            .x86_64 => {
-            argc_argv_ptr = asm (
+                argc_argv_ptr = asm volatile (
-                \\ mov %%g0, %%i6
+                    \\ xor %%rbp, %%rbp
-                \\ add %%o6, 2175, %[argc]
+                    : [argc] "={rsp}" (-> [*]usize),
-                : [argc] "=r" (-> [*]usize),
+                );
-            );
+            },
+            .i386 => {
+                argc_argv_ptr = asm volatile (
+                    \\ xor %%ebp, %%ebp
+                    : [argc] "={esp}" (-> [*]usize),
+                );
+            },
+            .aarch64, .aarch64_be, .arm, .armeb, .thumb => {
+                argc_argv_ptr = asm volatile (
+                    \\ mov fp, #0
+                    \\ mov lr, #0
+                    : [argc] "={sp}" (-> [*]usize),
+                );
+            },
+            .riscv64 => {
+                argc_argv_ptr = asm volatile (
+                    \\ li s0, 0
+                    \\ li ra, 0
+                    : [argc] "={sp}" (-> [*]usize),
+                );
+            },
+            .mips, .mipsel => {
+                // The lr is already zeroed on entry, as specified by the ABI.
+                argc_argv_ptr = asm volatile (
+                    \\ move $fp, $0
+                    : [argc] "={sp}" (-> [*]usize),
+                );
+            },
+            .powerpc => {
+                // Setup the initial stack frame and clear the back chain pointer.
+                argc_argv_ptr = asm volatile (
+                    \\ mr 4, 1
+                    \\ li 0, 0
+                    \\ stwu 1,-16(1)
+                    \\ stw 0, 0(1)
+                    \\ mtlr 0
+                    : [argc] "={r4}" (-> [*]usize),
+                    :
+                    : "r0"
+                );
+            },
+            .powerpc64le => {
+                // Setup the initial stack frame and clear the back chain pointer.
+                // TODO: Support powerpc64 (big endian) on ELFv2.
+                argc_argv_ptr = asm volatile (
+                    \\ mr 4, 1
+                    \\ li 0, 0
+                    \\ stdu 0, -32(1)
+                    \\ mtlr 0
+                    : [argc] "={r4}" (-> [*]usize),
+                    :
+                    : "r0"
+                );
+            },
+            .sparc64 => {
+                // argc is stored after a register window (16 registers) plus stack bias
+                argc_argv_ptr = asm (
+                    \\ mov %%g0, %%i6
+                    \\ add %%o6, 2175, %[argc]
+                    : [argc] "=r" (-> [*]usize),
+                );
+            },
+            else => @compileError("unsupported arch"),
         },
-        else => @compileError("unsupported arch"),
     }
     // If LLVM inlines stack variables into _start, they will overwrite
     // the command line argument data.
 @@ -363,7 +377,7 @@ fn wWinMainCRTStartup() callconv(std.os.windows.WINAPI) noreturn {
     std.os.windows.kernel32.ExitProcess(@bitCast(std.os.windows.UINT, result));
 }
-fn posixCallMainAndExit() noreturn {
+fn posixCallMainAndExit() callconv(.C) noreturn {
     @setAlignStack(16);
     const argc = argc_argv_ptr[0];
 @@ -462,7 +476,7 @@ fn callMainWithArgs(argc: usize, argv: [*][*:0]u8, envp: [][*:0]u8) u8 {
     return initEventLoopAndCallMain();
 }
-fn main(c_argc: i32, c_argv: [*][*:0]u8, c_envp: [*:null]?[*:0]u8) callconv(.C) i32 {
+fn main(c_argc: c_int, c_argv: [*c][*c]u8, c_envp: [*c][*c]u8) callconv(.C) c_int {
     var env_count: usize = 0;
     while (c_envp[env_count] != null) : (env_count += 1) {}
     const envp = @ptrCast([*][*:0]u8, c_envp)[0..env_count];
 @@ -474,10 +488,10 @@ fn main(c_argc: i32, c_argv: [*][*:0]u8, c_envp: [*:null]?[*:0]u8) callconv(.C)
         expandStackSize(phdrs);
     }
-    return @call(.{ .modifier = .always_inline }, callMainWithArgs, .{ @intCast(usize, c_argc), c_argv, envp });
+    return @call(.{ .modifier = .always_inline }, callMainWithArgs, .{ @intCast(usize, c_argc), @ptrCast([*][*:0]u8, c_argv), envp });
 }
-fn mainWithoutEnv(c_argc: i32, c_argv: [*][*:0]u8) callconv(.C) usize {
+fn mainWithoutEnv(c_argc: c_int, c_argv: [*c][*c]u8) callconv(.C) c_int {
     std.os.argv = c_argv[0..@intCast(usize, c_argc)];
     return @call(.{ .modifier = .always_inline }, callMain, .{});
 }

lib/test_runner.zig+2-1

...	@@ -8,7 +8,8 @@ var log_err_count: usize = 0;	...	@@ -8,7 +8,8 @@ var log_err_count: usize = 0;
8		8
9	pub fn main() void {	9	pub fn main() void {
10	if (builtin.zig_backend != .stage1 and	10	if (builtin.zig_backend != .stage1 and
11	(builtin.zig_backend != .stage2_llvm or builtin.cpu.arch == .wasm32))	11	(builtin.zig_backend != .stage2_llvm or builtin.cpu.arch == .wasm32) and
		12	builtin.zig_backend != .stage2_c)
12	{	13	{
13	return main2() catch @panic("test failure");	14	return main2() catch @panic("test failure");
14	}	15	}

src/codegen/c.zig+204-112

...	@@ -34,8 +34,8 @@ pub const CValue = union(enum) {	...	@@ -34,8 +34,8 @@ pub const CValue = union(enum) {
34	/// By-value	34	/// By-value
35	decl: Decl.Index,	35	decl: Decl.Index,
36	decl_ref: Decl.Index,	36	decl_ref: Decl.Index,
37	/// An undefined (void *) pointer (cannot be dereferenced)	37	/// An undefined value (cannot be dereferenced)
38	undefined_ptr: Type,	38	undef: Type,
39	/// Render the slice as an identifier (using fmtIdent)	39	/// Render the slice as an identifier (using fmtIdent)
40	identifier: []const u8,	40	identifier: []const u8,
41	/// Render these bytes literally.	41	/// Render these bytes literally.
...	@@ -342,8 +342,9 @@ pub const Function = struct {	...	@@ -342,8 +342,9 @@ pub const Function = struct {
342	const float_bits = float_ty.floatBits(target);	342	const float_bits = float_ty.floatBits(target);
343	const is_longdouble = float_bits == CType.longdouble.sizeInBits(target);	343	const is_longdouble = float_bits == CType.longdouble.sizeInBits(target);
344	const writer = f.object.writer();	344	const writer = f.object.writer();
345	if (!is_longdouble and float_bits == 80) {	345	try writer.writeAll("__");
346	try writer.writeAll("__");	346	if (is_longdouble or float_bits != 80) {
		347	try writer.writeAll("builtin_");
347	}	348	}
348	try writer.writeAll(fn_name);	349	try writer.writeAll(fn_name);
349	if (is_longdouble) {	350	if (is_longdouble) {
...	@@ -410,10 +411,17 @@ pub const DeclGen = struct {	...	@@ -410,10 +411,17 @@ pub const DeclGen = struct {
410	const decl = dg.module.declPtr(decl_index);	411	const decl = dg.module.declPtr(decl_index);
411	assert(decl.has_tv);	412	assert(decl.has_tv);
412		413
		414	// Render an undefined pointer if we have a pointer to a zero-bit or comptime type.
413	if (ty.isPtrAtRuntime() and !decl.ty.isFnOrHasRuntimeBits()) {	415	if (ty.isPtrAtRuntime() and !decl.ty.isFnOrHasRuntimeBits()) {
414	return dg.writeCValue(writer, CValue{ .undefined_ptr = ty });	416	return dg.writeCValue(writer, CValue{ .undef = ty });
415	}	417	}
416		418
		419	// Chase function values in order to be able to reference the original function.
		420	inline for (.{ .function, .extern_fn }) \|tag\|
		421	if (decl.val.castTag(tag)) \|func\|
		422	if (func.data.owner_decl != decl_index)
		423	return dg.renderDeclValue(writer, ty, val, func.data.owner_decl);
		424
417	if (ty.isSlice()) {	425	if (ty.isSlice()) {
418	try writer.writeByte('(');	426	try writer.writeByte('(');
419	try dg.renderTypecast(writer, ty);	427	try dg.renderTypecast(writer, ty);
...	@@ -588,9 +596,9 @@ pub const DeclGen = struct {	...	@@ -588,9 +596,9 @@ pub const DeclGen = struct {
588	try writer.writeByte('(');	596	try writer.writeByte('(');
589	try dg.renderTypecast(writer, ty);	597	try dg.renderTypecast(writer, ty);
590	try writer.writeAll("){ .payload = ");	598	try writer.writeAll("){ .payload = ");
591	try dg.renderValue(writer, Type.bool, val, location);
592	try writer.writeAll(", .is_null = ");
593	try dg.renderValue(writer, payload_ty, val, location);	599	try dg.renderValue(writer, payload_ty, val, location);
		600	try writer.writeAll(", .is_null = ");
		601	try dg.renderValue(writer, Type.bool, val, location);
594	return writer.writeAll(" }");	602	return writer.writeAll(" }");
595	},	603	},
596	.Struct => {	604	.Struct => {
...	@@ -635,7 +643,7 @@ pub const DeclGen = struct {	...	@@ -635,7 +643,7 @@ pub const DeclGen = struct {
635	try writer.writeAll("){ .payload = ");	643	try writer.writeAll("){ .payload = ");
636	try dg.renderValue(writer, ty.errorUnionPayload(), val, location);	644	try dg.renderValue(writer, ty.errorUnionPayload(), val, location);
637	return writer.print(", .error = {x} }}", .{	645	return writer.print(", .error = {x} }}", .{
638	try dg.fmtIntLiteral(ty.errorUnionSet(), Value.undef),	646	try dg.fmtIntLiteral(ty.errorUnionSet(), val),
639	});	647	});
640	},	648	},
641	.Array => {	649	.Array => {
...	@@ -844,13 +852,13 @@ pub const DeclGen = struct {	...	@@ -844,13 +852,13 @@ pub const DeclGen = struct {
844	}	852	}
845	},	853	},
846	.ErrorUnion => {	854	.ErrorUnion => {
847	const error_type = ty.errorUnionSet();	855	const error_ty = ty.errorUnionSet();
848	const payload_type = ty.errorUnionPayload();	856	const payload_ty = ty.errorUnionPayload();
849		857
850	if (!payload_type.hasRuntimeBits()) {	858	if (!payload_ty.hasRuntimeBits()) {
851	// We use the error type directly as the type.	859	// We use the error type directly as the type.
852	const err_val = if (val.errorUnionIsPayload()) Value.initTag(.zero) else val;	860	const err_val = if (val.errorUnionIsPayload()) Value.initTag(.zero) else val;
853	return dg.renderValue(writer, error_type, err_val, location);	861	return dg.renderValue(writer, error_ty, err_val, location);
854	}	862	}
855		863
856	try writer.writeByte('(');	864	try writer.writeByte('(');
...	@@ -859,11 +867,15 @@ pub const DeclGen = struct {	...	@@ -859,11 +867,15 @@ pub const DeclGen = struct {
859	if (val.castTag(.eu_payload)) \|pl\| {	867	if (val.castTag(.eu_payload)) \|pl\| {
860	const payload_val = pl.data;	868	const payload_val = pl.data;
861	try writer.writeAll(" .payload = ");	869	try writer.writeAll(" .payload = ");
862	try dg.renderValue(writer, payload_type, payload_val, location);	870	try dg.renderValue(writer, payload_ty, payload_val, location);
863	try writer.writeAll(", .error = 0 }");	871	try writer.print(", .error = {} }}", .{
		872	try dg.fmtIntLiteral(error_ty, Value.zero),
		873	});
864	} else {	874	} else {
865	try writer.writeAll(" .error = ");	875	try writer.writeAll(" .payload = ");
866	try dg.renderValue(writer, error_type, val, location);	876	try dg.renderValue(writer, payload_ty, Value.undef, location);
		877	try writer.writeAll(", .error = ");
		878	try dg.renderValue(writer, error_ty, val, location);
867	try writer.writeAll(" }");	879	try writer.writeAll(" }");
868	}	880	}
869	},	881	},
...	@@ -987,13 +999,16 @@ pub const DeclGen = struct {	...	@@ -987,13 +999,16 @@ pub const DeclGen = struct {
987	if (!is_global) {	999	if (!is_global) {
988	try w.writeAll("static ");	1000	try w.writeAll("static ");
989	}	1001	}
		1002	const fn_info = dg.decl.ty.fnInfo();
		1003	if (fn_info.cc == .Naked) {
		1004	try w.writeAll("ZIG_NAKED ");
		1005	}
990	if (dg.decl.val.castTag(.function)) \|func_payload\| {	1006	if (dg.decl.val.castTag(.function)) \|func_payload\| {
991	const func: *Module.Fn = func_payload.data;	1007	const func: *Module.Fn = func_payload.data;
992	if (func.is_cold) {	1008	if (func.is_cold) {
993	try w.writeAll("ZIG_COLD ");	1009	try w.writeAll("ZIG_COLD ");
994	}	1010	}
995	}	1011	}
996	const fn_info = dg.decl.ty.fnInfo();
997	if (fn_info.return_type.hasRuntimeBits()) {	1012	if (fn_info.return_type.hasRuntimeBits()) {
998	try dg.renderType(w, fn_info.return_type);	1013	try dg.renderType(w, fn_info.return_type);
999	} else if (fn_info.return_type.isError()) {	1014	} else if (fn_info.return_type.isError()) {
...	@@ -1007,21 +1022,21 @@ pub const DeclGen = struct {	...	@@ -1007,21 +1022,21 @@ pub const DeclGen = struct {
1007	try dg.renderDeclName(w, dg.decl_index);	1022	try dg.renderDeclName(w, dg.decl_index);
1008	try w.writeByte('(');	1023	try w.writeByte('(');
1009		1024
1010	var params_written: usize = 0;	1025	var index: usize = 0;
1011	for (fn_info.param_types) \|param_type, index\| {	1026	for (fn_info.param_types) \|param_type\| {
1012	if (!param_type.hasRuntimeBitsIgnoreComptime()) continue;	1027	if (!param_type.hasRuntimeBitsIgnoreComptime()) continue;
1013	if (params_written > 0) {	1028	if (index > 0) {
1014	try w.writeAll(", ");	1029	try w.writeAll(", ");
1015	}	1030	}
1016	const name = CValue{ .arg = index };	1031	const name = CValue{ .arg = index };
1017	try dg.renderTypeAndName(w, param_type, name, .Mut, 0);	1032	try dg.renderTypeAndName(w, param_type, name, .Mut, 0);
1018	params_written += 1;	1033	index += 1;
1019	}	1034	}
1020		1035
1021	if (fn_info.is_var_args) {	1036	if (fn_info.is_var_args) {
1022	if (params_written != 0) try w.writeAll(", ");	1037	if (index > 0) try w.writeAll(", ");
1023	try w.writeAll("...");	1038	try w.writeAll("...");
1024	} else if (params_written == 0) {	1039	} else if (index == 0) {
1025	try w.writeAll("void");	1040	try w.writeAll("void");
1026	}	1041	}
1027	try w.writeByte(')');	1042	try w.writeByte(')');
...	@@ -1307,7 +1322,7 @@ pub const DeclGen = struct {	...	@@ -1307,7 +1322,7 @@ pub const DeclGen = struct {
1307		1322
1308	fn renderErrorUnionTypedef(dg: *DeclGen, t: Type) error{ OutOfMemory, AnalysisFail }![]const u8 {	1323	fn renderErrorUnionTypedef(dg: *DeclGen, t: Type) error{ OutOfMemory, AnalysisFail }![]const u8 {
1309	const payload_ty = t.errorUnionPayload();	1324	const payload_ty = t.errorUnionPayload();
1310	const error_ty = t.errorUnionSet();	1325	assert(t.errorUnionSet().tag() == .anyerror);
1311		1326
1312	var buffer = std.ArrayList(u8).init(dg.typedefs.allocator);	1327	var buffer = std.ArrayList(u8).init(dg.typedefs.allocator);
1313	defer buffer.deinit();	1328	defer buffer.deinit();
...	@@ -1328,15 +1343,7 @@ pub const DeclGen = struct {	...	@@ -1328,15 +1343,7 @@ pub const DeclGen = struct {
1328	}	1343	}
1329		1344
1330	const name_begin = buffer.items.len;	1345	const name_begin = buffer.items.len;
1331	if (error_ty.castTag(.error_set_inferred)) \|inf_err_set_payload\| {	1346	try bw.print("zig_E_{}", .{typeToCIdentifier(payload_ty, dg.module)});
1332	const func = inf_err_set_payload.data.func;
1333	try bw.writeAll("zig_E_");
1334	try dg.renderDeclName(bw, func.owner_decl);
1335	} else {
1336	try bw.print("zig_E_{}_{}", .{
1337	typeToCIdentifier(error_ty, dg.module), typeToCIdentifier(payload_ty, dg.module),
1338	});
1339	}
1340	const name_end = buffer.items.len;	1347	const name_end = buffer.items.len;
1341	try bw.writeAll(";\n");	1348	try bw.writeAll(";\n");
1342		1349
...	@@ -1505,11 +1512,11 @@ pub const DeclGen = struct {	...	@@ -1505,11 +1512,11 @@ pub const DeclGen = struct {
1505	},	1512	},
1506	.Pointer => {	1513	.Pointer => {
1507	if (t.isSlice()) {	1514	if (t.isSlice()) {
1508	var slice_ty_pl = Type.Payload.ElemType{	1515	var slice_pl = Type.Payload.ElemType{
1509	.base = .{ .tag = if (t.ptrIsMutable()) .mut_slice else .const_slice },	1516	.base = .{ .tag = if (t.ptrIsMutable()) .mut_slice else .const_slice },
1510	.data = t.childType(),	1517	.data = t.childType(),
1511	};	1518	};
1512	const slice_ty = Type.initPayload(&slice_ty_pl.base);	1519	const slice_ty = Type.initPayload(&slice_pl.base);
1513		1520
1514	const name = dg.getTypedefName(slice_ty) orelse	1521	const name = dg.getTypedefName(slice_ty) orelse
1515	try dg.renderSliceTypedef(slice_ty);	1522	try dg.renderSliceTypedef(slice_ty);
...	@@ -1525,7 +1532,9 @@ pub const DeclGen = struct {	...	@@ -1525,7 +1532,9 @@ pub const DeclGen = struct {
1525	}	1532	}
1526		1533
1527	const child_ty = t.childType();	1534	const child_ty = t.childType();
1528	if (t.isCPtr() and child_ty.eql(Type.u8, dg.module) and dg.decl.val.tag() == .extern_fn) {	1535	if (t.isCPtr() and child_ty.eql(Type.u8, dg.module) and
		1536	(dg.decl.val.tag() == .extern_fn or std.mem.eql(u8, std.mem.span(dg.decl.name), "main")))
		1537	{
1529	// This is a hack, since the c compiler expects a lot of external	1538	// This is a hack, since the c compiler expects a lot of external
1530	// library functions to have char pointers in their signatures, but	1539	// library functions to have char pointers in their signatures, but
1531	// u8 and i8 produce unsigned char and signed char respectively,	1540	// u8 and i8 produce unsigned char and signed char respectively,
...	@@ -1543,11 +1552,11 @@ pub const DeclGen = struct {	...	@@ -1543,11 +1552,11 @@ pub const DeclGen = struct {
1543	return w.writeAll(" *");	1552	return w.writeAll(" *");
1544	},	1553	},
1545	.Array => {	1554	.Array => {
1546	var array_ty_pl = Type.Payload.Array{ .base = .{ .tag = .array }, .data = .{	1555	var array_pl = Type.Payload.Array{ .base = .{ .tag = .array }, .data = .{
1547	.len = t.arrayLenIncludingSentinel(),	1556	.len = t.arrayLenIncludingSentinel(),
1548	.elem_type = t.childType(),	1557	.elem_type = t.childType(),
1549	} };	1558	} };
1550	const array_ty = Type.initPayload(&array_ty_pl.base);	1559	const array_ty = Type.initPayload(&array_pl.base);
1551		1560
1552	const name = dg.getTypedefName(array_ty) orelse	1561	const name = dg.getTypedefName(array_ty) orelse
1553	try dg.renderArrayTypedef(array_ty);	1562	try dg.renderArrayTypedef(array_ty);
...	@@ -1582,8 +1591,13 @@ pub const DeclGen = struct {	...	@@ -1582,8 +1591,13 @@ pub const DeclGen = struct {
1582	return dg.renderType(w, Type.anyerror);	1591	return dg.renderType(w, Type.anyerror);
1583	}	1592	}
1584		1593
1585	const name = dg.getTypedefName(t) orelse	1594	var error_union_pl = Type.Payload.ErrorUnion{
1586	try dg.renderErrorUnionTypedef(t);	1595	.data = .{ .error_set = Type.anyerror, .payload = payload_ty },
		1596	};
		1597	const error_union_ty = Type.initPayload(&error_union_pl.base);
		1598
		1599	const name = dg.getTypedefName(error_union_ty) orelse
		1600	try dg.renderErrorUnionTypedef(error_union_ty);
1587		1601
1588	return w.writeAll(name);	1602	return w.writeAll(name);
1589	},	1603	},
...	@@ -1603,8 +1617,8 @@ pub const DeclGen = struct {	...	@@ -1603,8 +1617,8 @@ pub const DeclGen = struct {
1603	},	1617	},
1604	.Enum => {	1618	.Enum => {
1605	// For enums, we simply use the integer tag type.	1619	// For enums, we simply use the integer tag type.
1606	var int_tag_ty_buffer: Type.Payload.Bits = undefined;	1620	var int_tag_buf: Type.Payload.Bits = undefined;
1607	const int_tag_ty = t.intTagType(&int_tag_ty_buffer);	1621	const int_tag_ty = t.intTagType(&int_tag_buf);
1608		1622
1609	try dg.renderType(w, int_tag_ty);	1623	try dg.renderType(w, int_tag_ty);
1610	},	1624	},
...	@@ -1801,11 +1815,7 @@ pub const DeclGen = struct {	...	@@ -1801,11 +1815,7 @@ pub const DeclGen = struct {
1801	try w.writeByte('&');	1815	try w.writeByte('&');
1802	return dg.renderDeclName(w, decl);	1816	return dg.renderDeclName(w, decl);
1803	},	1817	},
1804	.undefined_ptr => \|ty\| {	1818	.undef => \|ty\| return dg.renderValue(w, ty, Value.undef, .Other),
1805	try w.writeAll("((");
1806	try dg.renderTypecast(w, ty);
1807	return w.print("){x})", .{try dg.fmtIntLiteral(Type.usize, Value.undef)});
1808	},
1809	.identifier => \|ident\| return w.print("{ }", .{fmtIdent(ident)}),	1819	.identifier => \|ident\| return w.print("{ }", .{fmtIdent(ident)}),
1810	.bytes => \|bytes\| return w.writeAll(bytes),	1820	.bytes => \|bytes\| return w.writeAll(bytes),
1811	}	1821	}
...	@@ -1824,7 +1834,7 @@ pub const DeclGen = struct {	...	@@ -1824,7 +1834,7 @@ pub const DeclGen = struct {
1824	return w.writeByte(')');	1834	return w.writeByte(')');
1825	},	1835	},
1826	.decl_ref => \|decl\| return dg.renderDeclName(w, decl),	1836	.decl_ref => \|decl\| return dg.renderDeclName(w, decl),
1827	.undefined_ptr => unreachable,	1837	.undef => unreachable,
1828	.identifier => \|ident\| return w.print("(*{ })", .{fmtIdent(ident)}),	1838	.identifier => \|ident\| return w.print("(*{ })", .{fmtIdent(ident)}),
1829	.bytes => \|bytes\| {	1839	.bytes => \|bytes\| {
1830	try w.writeAll("(*");	1840	try w.writeAll("(*");
...	@@ -2151,10 +2161,10 @@ fn genBody(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail, OutO	...	@@ -2151,10 +2161,10 @@ fn genBody(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail, OutO
2151		2161
2152	.mul_add => try airMulAdd(f, inst),	2162	.mul_add => try airMulAdd(f, inst),
2153		2163
2154	.add_with_overflow => try airOverflow(f, inst, "addo_"),	2164	.add_with_overflow => try airOverflow(f, inst, "addo_", .range),
2155	.sub_with_overflow => try airOverflow(f, inst, "subo_"),	2165	.sub_with_overflow => try airOverflow(f, inst, "subo_", .range),
2156	.mul_with_overflow => try airOverflow(f, inst, "mulo_"),	2166	.mul_with_overflow => try airOverflow(f, inst, "mulo_", .range),
2157	.shl_with_overflow => try airOverflow(f, inst, "shlo_"),	2167	.shl_with_overflow => try airOverflow(f, inst, "shlo_", .bits),
2158		2168
2159	.min => try airMinMax(f, inst, "<"),	2169	.min => try airMinMax(f, inst, "<"),
2160	.max => try airMinMax(f, inst, ">"),	2170	.max => try airMinMax(f, inst, ">"),
...	@@ -2284,8 +2294,8 @@ fn genBody(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail, OutO	...	@@ -2284,8 +2294,8 @@ fn genBody(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail, OutO
2284	.slice_ptr => try airSliceField(f, inst, " = ", ".ptr;\n"),	2294	.slice_ptr => try airSliceField(f, inst, " = ", ".ptr;\n"),
2285	.slice_len => try airSliceField(f, inst, " = ", ".len;\n"),	2295	.slice_len => try airSliceField(f, inst, " = ", ".len;\n"),
2286		2296
2287	.ptr_slice_len_ptr => try airSliceField(f, inst, " = &", ".len;\n"),	2297	.ptr_slice_len_ptr => try airSliceField(f, inst, " = &", "->len;\n"),
2288	.ptr_slice_ptr_ptr => try airSliceField(f, inst, " = &", ".ptr;\n"),	2298	.ptr_slice_ptr_ptr => try airSliceField(f, inst, " = &", "->ptr;\n"),
2289		2299
2290	.ptr_elem_val => try airPtrElemVal(f, inst),	2300	.ptr_elem_val => try airPtrElemVal(f, inst),
2291	.ptr_elem_ptr => try airPtrElemPtr(f, inst),	2301	.ptr_elem_ptr => try airPtrElemPtr(f, inst),
...	@@ -2459,7 +2469,7 @@ fn airAlloc(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -2459,7 +2469,7 @@ fn airAlloc(f: *Function, inst: Air.Inst.Index) !CValue {
2459	const elem_type = inst_ty.elemType();	2469	const elem_type = inst_ty.elemType();
2460	const mutability: Mutability = if (inst_ty.isConstPtr()) .Const else .Mut;	2470	const mutability: Mutability = if (inst_ty.isConstPtr()) .Const else .Mut;
2461	if (!elem_type.isFnOrHasRuntimeBitsIgnoreComptime()) {	2471	if (!elem_type.isFnOrHasRuntimeBitsIgnoreComptime()) {
2462	return CValue{ .undefined_ptr = inst_ty };	2472	return CValue{ .undef = inst_ty };
2463	}	2473	}
2464		2474
2465	const target = f.object.dg.module.getTarget();	2475	const target = f.object.dg.module.getTarget();
...	@@ -2474,9 +2484,13 @@ fn airRetPtr(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -2474,9 +2484,13 @@ fn airRetPtr(f: *Function, inst: Air.Inst.Index) !CValue {
2474	const writer = f.object.writer();	2484	const writer = f.object.writer();
2475	const inst_ty = f.air.typeOfIndex(inst);	2485	const inst_ty = f.air.typeOfIndex(inst);
2476		2486
		2487	const elem_ty = inst_ty.elemType();
		2488	if (!elem_ty.hasRuntimeBitsIgnoreComptime()) {
		2489	return CValue{ .undef = inst_ty };
		2490	}
		2491
2477	// First line: the variable used as data storage.	2492	// First line: the variable used as data storage.
2478	const elem_type = inst_ty.elemType();	2493	const local = try f.allocLocal(elem_ty, .Mut);
2479	const local = try f.allocLocal(elem_type, .Mut);
2480	try writer.writeAll(";\n");	2494	try writer.writeAll(";\n");
2481		2495
2482	return CValue{ .local_ref = local.local };	2496	return CValue{ .local_ref = local.local };
...	@@ -2507,8 +2521,7 @@ fn airLoad(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -2507,8 +2521,7 @@ fn airLoad(f: *Function, inst: Air.Inst.Index) !CValue {
2507	if (is_array) {	2521	if (is_array) {
2508	// Insert a memcpy to initialize this array. The source operand is always a pointer	2522	// Insert a memcpy to initialize this array. The source operand is always a pointer
2509	// and thus we only need to know size/type information from the local type/dest.	2523	// and thus we only need to know size/type information from the local type/dest.
2510	try writer.writeByte(';');	2524	try writer.writeAll(";\n");
2511	try f.object.indent_writer.insertNewline();
2512	try writer.writeAll("memcpy(");	2525	try writer.writeAll("memcpy(");
2513	try f.writeCValue(writer, local);	2526	try f.writeCValue(writer, local);
2514	try writer.writeAll(", ");	2527	try writer.writeAll(", ");
...	@@ -2535,7 +2548,8 @@ fn airRet(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -2535,7 +2548,8 @@ fn airRet(f: *Function, inst: Air.Inst.Index) !CValue {
2535	try writer.writeAll(";\n");	2548	try writer.writeAll(";\n");
2536	} else if (ret_ty.isError()) {	2549	} else if (ret_ty.isError()) {
2537	try writer.writeAll("return 0;");	2550	try writer.writeAll("return 0;");
2538	} else {	2551	} else if (f.object.dg.decl.ty.fnCallingConvention() != .Naked) {
		2552	// Not even allowed to return void in a naked function.
2539	try writer.writeAll("return;\n");	2553	try writer.writeAll("return;\n");
2540	}	2554	}
2541	return CValue.none;	2555	return CValue.none;
...	@@ -2847,7 +2861,7 @@ fn airSatOp(f: Function, inst: Air.Inst.Index, fn_op: [:0]const u8) !CValue {	...	@@ -2847,7 +2861,7 @@ fn airSatOp(f: Function, inst: Air.Inst.Index, fn_op: [:0]const u8) !CValue {
2847	return ret;	2861	return ret;
2848	}	2862	}
2849		2863
2850	fn airOverflow(f: Function, inst: Air.Inst.Index, op_abbrev: [:0]const u8) !CValue {	2864	fn airOverflow(f: Function, inst: Air.Inst.Index, op_abbrev: [:0]const u8, kind: enum { range, bits }) !CValue {
2851	if (f.liveness.isUnused(inst))	2865	if (f.liveness.isUnused(inst))
2852	return CValue.none;	2866	return CValue.none;
2853		2867
...	@@ -2879,23 +2893,29 @@ fn airOverflow(f: Function, inst: Air.Inst.Index, op_abbrev: [:0]const u8) !CV	...	@@ -2879,23 +2893,29 @@ fn airOverflow(f: Function, inst: Air.Inst.Index, op_abbrev: [:0]const u8) !CV
2879	try w.writeAll(", &");	2893	try w.writeAll(", &");
2880	try f.writeCValue(w, ret);	2894	try f.writeCValue(w, ret);
2881	try w.writeAll(".field_0, ");	2895	try w.writeAll(".field_0, ");
2882	{	2896	switch (kind) {
2883	var arena = std.heap.ArenaAllocator.init(f.object.dg.module.gpa);	2897	.range => {
2884	defer arena.deinit();	2898	var arena = std.heap.ArenaAllocator.init(f.object.dg.module.gpa);
2885		2899	defer arena.deinit();
2886	const expected_contents = union { u: Value.Payload.U64, i: Value.Payload.I64 };	2900
2887	var stack align(@alignOf(expected_contents)) =	2901	const expected_contents = union { u: Value.Payload.U64, i: Value.Payload.I64 };
2888	std.heap.stackFallback(@sizeOf(expected_contents), arena.allocator());	2902	var stack align(@alignOf(expected_contents)) =
2889		2903	std.heap.stackFallback(@sizeOf(expected_contents), arena.allocator());
2890	if (int_info.signedness == .signed) {	2904
2891	const min_val = try scalar_ty.minInt(stack.get(), target);	2905	if (int_info.signedness == .signed) {
2892	try w.print("{}, ", .{try f.fmtIntLiteral(scalar_ty, min_val)});	2906	const min_val = try scalar_ty.minInt(stack.get(), target);
2893	}	2907	try w.print("{}, ", .{try f.fmtIntLiteral(scalar_ty, min_val)});
		2908	}
2894		2909
2895	const max_val = try scalar_ty.maxInt(stack.get(), target);	2910	const max_val = try scalar_ty.maxInt(stack.get(), target);
2896	try w.print("{});", .{try f.fmtIntLiteral(scalar_ty, max_val)});	2911	try w.print("{});\n", .{try f.fmtIntLiteral(scalar_ty, max_val)});
		2912	},
		2913	.bits => {
		2914	var bits_pl = Value.Payload.U64{ .base = .{ .tag = .int_u64 }, .data = int_info.bits };
		2915	const bits_val = Value.initPayload(&bits_pl.base);
		2916	try w.print("{x});\n", .{try f.fmtIntLiteral(Type.u8, bits_val)});
		2917	},
2897	}	2918	}
2898	try f.object.indent_writer.insertNewline();
2899	return ret;	2919	return ret;
2900	}	2920	}
2901		2921
...	@@ -3075,6 +3095,9 @@ fn airCall(	...	@@ -3075,6 +3095,9 @@ fn airCall(
3075	inst: Air.Inst.Index,	3095	inst: Air.Inst.Index,
3076	modifier: std.builtin.CallOptions.Modifier,	3096	modifier: std.builtin.CallOptions.Modifier,
3077	) !CValue {	3097	) !CValue {
		3098	// Not even allowed to call panic in a naked function.
		3099	if (f.object.dg.decl.ty.fnCallingConvention() == .Naked) return .none;
		3100
3078	switch (modifier) {	3101	switch (modifier) {
3079	.auto => {},	3102	.auto => {},
3080	.always_tail => return f.fail("TODO: C backend: call with always_tail attribute", .{}),	3103	.always_tail => return f.fail("TODO: C backend: call with always_tail attribute", .{}),
...	@@ -3094,10 +3117,10 @@ fn airCall(	...	@@ -3094,10 +3117,10 @@ fn airCall(
3094	const writer = f.object.writer();	3117	const writer = f.object.writer();
3095		3118
3096	const result_local: CValue = r: {	3119	const result_local: CValue = r: {
3097	if (f.liveness.isUnused(inst)) {	3120	if (!loweredFnRetTyHasBits(fn_ty)) {
3098	if (loweredFnRetTyHasBits(fn_ty)) {	3121	break :r .none;
3099	try writer.print("(void)", .{});	3122	} else if (f.liveness.isUnused(inst)) {
3100	}	3123	try writer.print("(void)", .{});
3101	break :r .none;	3124	break :r .none;
3102	} else {	3125	} else {
3103	const local = try f.allocLocal(fn_ty.fnReturnType(), .Const);	3126	const local = try f.allocLocal(fn_ty.fnReturnType(), .Const);
...	@@ -3107,6 +3130,7 @@ fn airCall(	...	@@ -3107,6 +3130,7 @@ fn airCall(
3107	};	3130	};
3108		3131
3109	var is_extern = false;	3132	var is_extern = false;
		3133	var name: [*:0]const u8 = "";
3110	callee: {	3134	callee: {
3111	known: {	3135	known: {
3112	const fn_decl = fn_decl: {	3136	const fn_decl = fn_decl: {
...	@@ -3121,6 +3145,7 @@ fn airCall(	...	@@ -3121,6 +3145,7 @@ fn airCall(
3121	else => break :known,	3145	else => break :known,
3122	};	3146	};
3123	};	3147	};
		3148	name = f.object.dg.module.declPtr(fn_decl).name;
3124	try f.object.dg.renderDeclName(writer, fn_decl);	3149	try f.object.dg.renderDeclName(writer, fn_decl);
3125	break :callee;	3150	break :callee;
3126	}	3151	}
...	@@ -3137,7 +3162,9 @@ fn airCall(	...	@@ -3137,7 +3162,9 @@ fn airCall(
3137	if (args_written != 0) {	3162	if (args_written != 0) {
3138	try writer.writeAll(", ");	3163	try writer.writeAll(", ");
3139	}	3164	}
3140	if (is_extern and ty.isCPtr() and ty.childType().tag() == .u8) {	3165	if ((is_extern or std.mem.eql(u8, std.mem.span(name), "main")) and
		3166	ty.isCPtr() and ty.childType().tag() == .u8)
		3167	{
3141	// Corresponds with hack in renderType .Pointer case.	3168	// Corresponds with hack in renderType .Pointer case.
3142	try writer.writeAll("(char");	3169	try writer.writeAll("(char");
3143	if (ty.isConstPtr()) try writer.writeAll(" const");	3170	if (ty.isConstPtr()) try writer.writeAll(" const");
...	@@ -3286,15 +3313,27 @@ fn lowerTry(	...	@@ -3286,15 +3313,27 @@ fn lowerTry(
3286	}	3313	}
3287	}	3314	}
3288		3315
3289	const local = try f.allocLocal(result_ty, .Const);	3316	const is_array = payload_ty.zigTypeTag() == .Array;
3290	if (operand_is_ptr or isByRef(payload_ty)) {	3317	const local = try f.allocLocal(result_ty, if (is_array) .Mut else .Const);
3291	try writer.writeAll(" = &");	3318	if (is_array) {
		3319	try writer.writeAll(";\n");
		3320	try writer.writeAll("memcpy(");
		3321	try f.writeCValue(writer, local);
		3322	try writer.writeAll(", ");
3292	try f.writeCValue(writer, err_union);	3323	try f.writeCValue(writer, err_union);
3293	try writer.writeAll("->payload;\n");	3324	try writer.writeAll(".payload, sizeof(");
		3325	try f.writeCValue(writer, local);
		3326	try writer.writeAll("));\n");
3294	} else {	3327	} else {
3295	try writer.writeAll(" = ");	3328	if (operand_is_ptr or isByRef(payload_ty)) {
3296	try f.writeCValue(writer, err_union);	3329	try writer.writeAll(" = &");
3297	try writer.writeAll(".payload;\n");	3330	try f.writeCValue(writer, err_union);
		3331	try writer.writeAll("->payload;\n");
		3332	} else {
		3333	try writer.writeAll(" = ");
		3334	try f.writeCValue(writer, err_union);
		3335	try writer.writeAll(".payload;\n");
		3336	}
3298	}	3337	}
3299	return local;	3338	return local;
3300	}	3339	}
...	@@ -3361,15 +3400,21 @@ fn airBreakpoint(f: *Function) !CValue {	...	@@ -3361,15 +3400,21 @@ fn airBreakpoint(f: *Function) !CValue {
3361		3400
3362	fn airRetAddr(f: *Function, inst: Air.Inst.Index) !CValue {	3401	fn airRetAddr(f: *Function, inst: Air.Inst.Index) !CValue {
3363	if (f.liveness.isUnused(inst)) return CValue.none;	3402	if (f.liveness.isUnused(inst)) return CValue.none;
		3403	const writer = f.object.writer();
3364	const local = try f.allocLocal(Type.usize, .Const);	3404	const local = try f.allocLocal(Type.usize, .Const);
3365	try f.object.writer().writeAll(" = zig_return_address();\n");	3405	try writer.writeAll(" = (");
		3406	try f.renderTypecast(writer, Type.usize);
		3407	try writer.writeAll(")zig_return_address();\n");
3366	return local;	3408	return local;
3367	}	3409	}
3368		3410
3369	fn airFrameAddress(f: *Function, inst: Air.Inst.Index) !CValue {	3411	fn airFrameAddress(f: *Function, inst: Air.Inst.Index) !CValue {
3370	if (f.liveness.isUnused(inst)) return CValue.none;	3412	if (f.liveness.isUnused(inst)) return CValue.none;
		3413	const writer = f.object.writer();
3371	const local = try f.allocLocal(Type.usize, .Const);	3414	const local = try f.allocLocal(Type.usize, .Const);
3372	try f.object.writer().writeAll(" = zig_frame_address();\n");	3415	try writer.writeAll(" = (");
		3416	try f.renderTypecast(writer, Type.usize);
		3417	try writer.writeAll(")zig_frame_address();\n");
3373	return local;	3418	return local;
3374	}	3419	}
3375		3420
...	@@ -3385,6 +3430,9 @@ fn airFence(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -3385,6 +3430,9 @@ fn airFence(f: *Function, inst: Air.Inst.Index) !CValue {
3385	}	3430	}
3386		3431
3387	fn airUnreach(f: *Function) !CValue {	3432	fn airUnreach(f: *Function) !CValue {
		3433	// Not even allowed to call unreachable in a naked function.
		3434	if (f.object.dg.decl.ty.fnCallingConvention() == .Naked) return .none;
		3435
3388	try f.object.writer().writeAll("zig_unreachable();\n");	3436	try f.object.writer().writeAll("zig_unreachable();\n");
3389	return CValue.none;	3437	return CValue.none;
3390	}	3438	}
...	@@ -3479,15 +3527,12 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -3479,15 +3527,12 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
3479	const local = try f.allocLocal(inst_ty, .Mut);	3527	const local = try f.allocLocal(inst_ty, .Mut);
3480	if (f.wantSafety()) {	3528	if (f.wantSafety()) {
3481	try writer.writeAll(" = ");	3529	try writer.writeAll(" = ");
3482	try f.object.dg.renderValue(writer, inst_ty, Value.undef, .Other);	3530	try f.writeCValue(writer, .{ .undef = inst_ty });
3483	}	3531	}
3484	try writer.writeAll(";\n");	3532	try writer.writeAll(";\n");
3485	break :local local;	3533	break :local local;
3486	} else .none;	3534	} else .none;
3487		3535
3488	try writer.writeAll("{\n");
3489	f.object.indent_writer.pushIndent();
3490
3491	const output_locals_begin = f.next_local_index;	3536	const output_locals_begin = f.next_local_index;
3492	f.next_local_index += outputs.len;	3537	f.next_local_index += outputs.len;
3493	const constraints_extra_begin = extra_i;	3538	const constraints_extra_begin = extra_i;
...	@@ -3510,7 +3555,7 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -3510,7 +3555,7 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
3510	try writer.writeAll("\")");	3555	try writer.writeAll("\")");
3511	if (f.wantSafety()) {	3556	if (f.wantSafety()) {
3512	try writer.writeAll(" = ");	3557	try writer.writeAll(" = ");
3513	try f.object.dg.renderValue(writer, output_ty, Value.undef, .Other);	3558	try f.writeCValue(writer, .{ .undef = output_ty });
3514	}	3559	}
3515	try writer.writeAll(";\n");	3560	try writer.writeAll(";\n");
3516	} else if (constraint.len < 2 or constraint[0] != '=') {	3561	} else if (constraint.len < 2 or constraint[0] != '=') {
...	@@ -3605,7 +3650,7 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -3605,7 +3650,7 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
3605	} else {	3650	} else {
3606	const input_val = try f.resolveInst(input);	3651	const input_val = try f.resolveInst(input);
3607	try writer.print("{s}(", .{fmtStringLiteral(constraint)});	3652	try writer.print("{s}(", .{fmtStringLiteral(constraint)});
3608	try f.writeCValue(writer, if (input_val == .constant) .{	3653	try f.writeCValue(writer, if (input_val == .constant) CValue{
3609	.local = input_locals_begin + index,	3654	.local = input_locals_begin + index,
3610	} else input_val);	3655	} else input_val);
3611	}	3656	}
...	@@ -3647,9 +3692,6 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -3647,9 +3692,6 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
3647	}	3692	}
3648	}	3693	}
3649		3694
3650	f.object.indent_writer.popIndent();
3651	try writer.writeAll("}\n");
3652
3653	return local;	3695	return local;
3654	}	3696	}
3655		3697
...	@@ -3728,7 +3770,7 @@ fn airOptionalPayloadPtr(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -3728,7 +3770,7 @@ fn airOptionalPayloadPtr(f: *Function, inst: Air.Inst.Index) !CValue {
3728	const inst_ty = f.air.typeOfIndex(inst);	3770	const inst_ty = f.air.typeOfIndex(inst);
3729		3771
3730	if (!inst_ty.childType().hasRuntimeBitsIgnoreComptime()) {	3772	if (!inst_ty.childType().hasRuntimeBitsIgnoreComptime()) {
3731	return CValue{ .undefined_ptr = inst_ty };	3773	return CValue{ .undef = inst_ty };
3732	}	3774	}
3733		3775
3734	if (opt_ty.optionalReprIsPayload()) {	3776	if (opt_ty.optionalReprIsPayload()) {
...	@@ -3996,7 +4038,9 @@ fn airWrapErrUnionErr(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -3996,7 +4038,9 @@ fn airWrapErrUnionErr(f: *Function, inst: Air.Inst.Index) !CValue {
3996	}	4038	}
3997		4039
3998	const local = try f.allocLocal(err_un_ty, .Const);	4040	const local = try f.allocLocal(err_un_ty, .Const);
3999	try writer.writeAll(" = { .error = ");	4041	try writer.writeAll(" = { .payload = ");
		4042	try f.writeCValue(writer, .{ .undef = payload_ty });
		4043	try writer.writeAll(", .error = ");
4000	try f.writeCValue(writer, operand);	4044	try f.writeCValue(writer, operand);
4001	try writer.writeAll(" };\n");	4045	try writer.writeAll(" };\n");
4002	return local;	4046	return local;
...	@@ -4059,10 +4103,25 @@ fn airWrapErrUnionPay(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -4059,10 +4103,25 @@ fn airWrapErrUnionPay(f: *Function, inst: Air.Inst.Index) !CValue {
4059	const operand = try f.resolveInst(ty_op.operand);	4103	const operand = try f.resolveInst(ty_op.operand);
4060		4104
4061	const inst_ty = f.air.typeOfIndex(inst);	4105	const inst_ty = f.air.typeOfIndex(inst);
4062	const local = try f.allocLocal(inst_ty, .Const);	4106	const payload_ty = inst_ty.errorUnionPayload();
4063	try writer.writeAll(" = { .error = 0, .payload = ");	4107	const is_array = payload_ty.zigTypeTag() == .Array;
4064	try f.writeCValue(writer, operand);	4108	const local = try f.allocLocal(inst_ty, if (is_array) .Mut else .Const);
4065	try writer.writeAll(" };\n");	4109	try writer.writeAll(" = { .payload = ");
		4110	try f.writeCValue(writer, if (is_array) CValue{ .undef = payload_ty } else operand);
		4111	try writer.print(", .error = {} }};\n", .{
		4112	try f.fmtIntLiteral(inst_ty.errorUnionSet(), Value.zero),
		4113	});
		4114
		4115	if (is_array) {
		4116	try writer.writeAll("memcpy(");
		4117	try f.writeCValue(writer, local);
		4118	try writer.writeAll(".payload, ");
		4119	try f.writeCValue(writer, operand);
		4120	try writer.writeAll(", sizeof(");
		4121	try f.writeCValue(writer, local);
		4122	try writer.writeAll(".payload));\n");
		4123	}
		4124
4066	return local;	4125	return local;
4067	}	4126	}
4068		4127
...	@@ -4114,11 +4173,11 @@ fn airArrayToSlice(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -4114,11 +4173,11 @@ fn airArrayToSlice(f: *Function, inst: Air.Inst.Index) !CValue {
4114	const array_len = f.air.typeOf(ty_op.operand).elemType().arrayLen();	4173	const array_len = f.air.typeOf(ty_op.operand).elemType().arrayLen();
4115		4174
4116	try writer.writeAll(" = { .ptr = ");	4175	try writer.writeAll(" = { .ptr = ");
4117	if (operand == .undefined_ptr) {	4176	if (operand == .undef) {
4118	// Unfortunately, C does not support any equivalent to	4177	// Unfortunately, C does not support any equivalent to
4119	// &((void )p)[0], although LLVM does via GetElementPtr	4178	// &((void )p)[0], although LLVM does via GetElementPtr
4120	var buf: Type.SlicePtrFieldTypeBuffer = undefined;	4179	var buf: Type.SlicePtrFieldTypeBuffer = undefined;
4121	try f.writeCValue(writer, CValue{ .undefined_ptr = inst_ty.slicePtrFieldType(&buf) });	4180	try f.writeCValue(writer, CValue{ .undef = inst_ty.slicePtrFieldType(&buf) });
4122	} else {	4181	} else {
4123	try writer.writeAll("&(");	4182	try writer.writeAll("&(");
4124	try f.writeCValueDeref(writer, operand);	4183	try f.writeCValueDeref(writer, operand);
...	@@ -4528,9 +4587,12 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -4528,9 +4587,12 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {
4528	const ty_pl = f.air.instructions.items(.data)[inst].ty_pl;	4587	const ty_pl = f.air.instructions.items(.data)[inst].ty_pl;
4529	const len = @intCast(usize, inst_ty.arrayLen());	4588	const len = @intCast(usize, inst_ty.arrayLen());
4530	const elements = @ptrCast([]const Air.Inst.Ref, f.air.extra[ty_pl.payload..][0..len]);	4589	const elements = @ptrCast([]const Air.Inst.Ref, f.air.extra[ty_pl.payload..][0..len]);
		4590	const mutability: Mutability = for (elements) \|element\| {
		4591	if (f.air.typeOf(element).zigTypeTag() == .Array) break .Mut;
		4592	} else .Const;
4531		4593
4532	const writer = f.object.writer();	4594	const writer = f.object.writer();
4533	const local = try f.allocLocal(inst_ty, .Const);	4595	const local = try f.allocLocal(inst_ty, mutability);
4534	try writer.writeAll(" = {");	4596	try writer.writeAll(" = {");
4535	switch (inst_ty.zigTypeTag()) {	4597	switch (inst_ty.zigTypeTag()) {
4536	.Array => {	4598	.Array => {
...	@@ -4547,6 +4609,7 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -4547,6 +4609,7 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {
4547	empty = false;	4609	empty = false;
4548	}	4610	}
4549	if (empty) try writer.print("{}", .{try f.fmtIntLiteral(Type.u8, Value.zero)});	4611	if (empty) try writer.print("{}", .{try f.fmtIntLiteral(Type.u8, Value.zero)});
		4612	try writer.writeAll("};\n");
4550	},	4613	},
4551	.Struct => {	4614	.Struct => {
4552	var empty = true;	4615	var empty = true;
...	@@ -4557,15 +4620,44 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -4557,15 +4620,44 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {
4557	if (!inst_ty.isTupleOrAnonStruct()) {	4620	if (!inst_ty.isTupleOrAnonStruct()) {
4558	try writer.print(".{ } = ", .{fmtIdent(inst_ty.structFieldName(index))});	4621	try writer.print(".{ } = ", .{fmtIdent(inst_ty.structFieldName(index))});
4559	}	4622	}
4560	try f.writeCValue(writer, try f.resolveInst(element));	4623
		4624	const element_ty = f.air.typeOf(element);
		4625	try f.writeCValue(writer, switch (element_ty.zigTypeTag()) {
		4626	.Array => CValue{ .undef = element_ty },
		4627	else => try f.resolveInst(element),
		4628	});
4561	empty = false;	4629	empty = false;
4562	}	4630	}
4563	if (empty) try writer.print("{}", .{try f.fmtIntLiteral(Type.u8, Value.zero)});	4631	if (empty) try writer.print("{}", .{try f.fmtIntLiteral(Type.u8, Value.zero)});
		4632	try writer.writeAll("};\n");
		4633
		4634	for (elements) \|element, index\| {
		4635	if (inst_ty.structFieldValueComptime(index)) \|_\| continue;
		4636
		4637	const element_ty = f.air.typeOf(element);
		4638	if (element_ty.zigTypeTag() != .Array) continue;
		4639
		4640	var field_name_storage: ?[]u8 = null;
		4641	defer if (field_name_storage) \|storage\| f.object.dg.gpa.free(storage);
		4642	const field_name = if (inst_ty.isTupleOrAnonStruct()) field_name: {
		4643	const name = try std.fmt.allocPrint(f.object.dg.gpa, "field_{d}", .{index});
		4644	field_name_storage = name;
		4645	break :field_name name;
		4646	} else inst_ty.structFieldName(index);
		4647
		4648	try writer.writeAll(";\n");
		4649	try writer.writeAll("memcpy(");
		4650	try f.writeCValue(writer, local);
		4651	try writer.print(".{ }, ", .{fmtIdent(field_name)});
		4652	try f.writeCValue(writer, try f.resolveInst(element));
		4653	try writer.writeAll(", sizeof(");
		4654	try f.writeCValue(writer, local);
		4655	try writer.print(".{ }));\n", .{fmtIdent(field_name)});
		4656	}
4564	},	4657	},
4565	.Vector => return f.fail("TODO: C backend: implement airAggregateInit for vectors", .{}),	4658	.Vector => return f.fail("TODO: C backend: implement airAggregateInit for vectors", .{}),
4566	else => unreachable,	4659	else => unreachable,
4567	}	4660	}
4568	try writer.writeAll("};\n");
4569		4661
4570	return local;	4662	return local;
4571	}	4663	}
...	@@ -4732,8 +4824,8 @@ fn airMulAdd(f: *Function, inst: Air.Inst.Index) !CValue {	...	@@ -4732,8 +4824,8 @@ fn airMulAdd(f: *Function, inst: Air.Inst.Index) !CValue {
4732		4824
4733	fn toMemoryOrder(order: std.builtin.AtomicOrder) [:0]const u8 {	4825	fn toMemoryOrder(order: std.builtin.AtomicOrder) [:0]const u8 {
4734	return switch (order) {	4826	return switch (order) {
4735	.Unordered => "memory_order_relaxed",	4827	// Note: unordered is actually even less atomic than relaxed
4736	.Monotonic => "memory_order_consume",	4828	.Unordered, .Monotonic => "memory_order_relaxed",
4737	.Acquire => "memory_order_acquire",	4829	.Acquire => "memory_order_acquire",
4738	.Release => "memory_order_release",	4830	.Release => "memory_order_release",
4739	.AcqRel => "memory_order_acq_rel",	4831	.AcqRel => "memory_order_acq_rel",

src/main.zig+4-1

 @@ -3018,7 +3018,10 @@ fn buildOutputType(
         const c_code_path = try fs.path.join(arena, &[_][]const u8{
             c_code_directory.path orelse ".", c_code_loc.basename,
         });
-        try test_exec_args.appendSlice(&.{ self_exe_path, "run", "-lc", c_code_path });
+        try test_exec_args.append(self_exe_path);
+        try test_exec_args.append("run");
+        if (link_libc) try test_exec_args.append("-lc");
+        try test_exec_args.append(c_code_path);
     }
     const run_or_test = switch (arg_mode) {

test/behavior/bugs/3742.zig-1

...	@@ -38,6 +38,5 @@ test "fixed" {	...	@@ -38,6 +38,5 @@ test "fixed" {
38	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;	38	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
39	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;	39	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
40	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;	40	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
41	if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
42	ArgSerializer.serializeCommand(GET.init("banana"));	41	ArgSerializer.serializeCommand(GET.init("banana"));
43	}	42	}

test/behavior/fn.zig-1

...	@@ -272,7 +272,6 @@ test "void parameters" {	...	@@ -272,7 +272,6 @@ test "void parameters" {
272	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;	272	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
273	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;	273	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
274		274
275	if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
276	try voidFun(1, void{}, 2, {});	275	try voidFun(1, void{}, 2, {});
277	}	276	}
278	fn voidFun(a: i32, b: void, c: i32, d: void) !void {	277	fn voidFun(a: i32, b: void, c: i32, d: void) !void {

test/behavior/struct.zig-2

...	@@ -1163,7 +1163,6 @@ test "for loop over pointers to struct, getting field from struct pointer" {	...	@@ -1163,7 +1163,6 @@ test "for loop over pointers to struct, getting field from struct pointer" {
1163		1163
1164	test "anon init through error unions and optionals" {	1164	test "anon init through error unions and optionals" {
1165	if (builtin.zig_backend == .stage1) return error.SkipZigTest;	1165	if (builtin.zig_backend == .stage1) return error.SkipZigTest;
1166	if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
1167	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO	1166	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
1168	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO	1167	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
1169	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO	1168	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
...	@@ -1234,7 +1233,6 @@ test "anon init through error union" {	...	@@ -1234,7 +1233,6 @@ test "anon init through error union" {
1234		1233
1235	test "typed init through error unions and optionals" {	1234	test "typed init through error unions and optionals" {
1236	if (builtin.zig_backend == .stage1) return error.SkipZigTest;	1235	if (builtin.zig_backend == .stage1) return error.SkipZigTest;
1237	if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
1238	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO	1236	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
1239	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO	1237	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
1240	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO	1238	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO

test/behavior/translate_c_macros.zig-1

...	@@ -100,7 +100,6 @@ test "nested comma operator" {	...	@@ -100,7 +100,6 @@ test "nested comma operator" {
100	test "cast functions" {	100	test "cast functions" {
101	if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO	101	if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
102	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO	102	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
103	if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
104	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO	103	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
105	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO	104	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
106		105