compiler_rt: fix and simplify additional Windows exports

Simplifies the logic, clarifies the comment, and fixes a minor bug,
which is that we exported the Windows ABI name *instead* of the standard
compiler-rt name, but it's meant to be exported *in addition* to the
standard name (this is LLVM's behavior and it is more useful).

lib/compiler_rt/arm.zig

@@ -15,11 +15,16 @@ comptime {
             @export(&__aeabi_unwind_cpp_pr1, .{ .name = "__aeabi_unwind_cpp_pr1", .linkage = common.linkage, .visibility = common.visibility });
             @export(&__aeabi_unwind_cpp_pr2, .{ .name = "__aeabi_unwind_cpp_pr2", .linkage = common.linkage, .visibility = common.visibility });
 
-            @export(&__aeabi_ldivmod, .{ .name = if (common.want_windows_arm_abi) "__rt_sdiv64" else "__aeabi_ldivmod", .linkage = common.linkage, .visibility = common.visibility });
+            if (common.want_windows_arm_abi) {
-            @export(&__aeabi_uldivmod, .{ .name = if (common.want_windows_arm_abi) "__rt_udiv64" else "__aeabi_uldivmod", .linkage = common.linkage, .visibility = common.visibility });
+                @export(&__aeabi_ldivmod, .{ .name = "__rt_sdiv64", .linkage = common.linkage, .visibility = common.visibility });
-
+                @export(&__aeabi_uldivmod, .{ .name = "__rt_udiv64", .linkage = common.linkage, .visibility = common.visibility });
-            @export(&__aeabi_idivmod, .{ .name = if (common.want_windows_arm_abi) "__rt_sdiv" else "__aeabi_idivmod", .linkage = common.linkage, .visibility = common.visibility });
+                @export(&__aeabi_idivmod, .{ .name = "__rt_sdiv", .linkage = common.linkage, .visibility = common.visibility });
-            @export(&__aeabi_uidivmod, .{ .name = if (common.want_windows_arm_abi) "__rt_udiv" else "__aeabi_uidivmod", .linkage = common.linkage, .visibility = common.visibility });
+                @export(&__aeabi_uidivmod, .{ .name = "__rt_udiv", .linkage = common.linkage, .visibility = common.visibility });
+            }
+            @export(&__aeabi_ldivmod, .{ .name = "__aeabi_ldivmod", .linkage = common.linkage, .visibility = common.visibility });
+            @export(&__aeabi_uldivmod, .{ .name = "__aeabi_uldivmod", .linkage = common.linkage, .visibility = common.visibility });
+            @export(&__aeabi_idivmod, .{ .name = "__aeabi_idivmod", .linkage = common.linkage, .visibility = common.visibility });
+            @export(&__aeabi_uidivmod, .{ .name = "__aeabi_uidivmod", .linkage = common.linkage, .visibility = common.visibility });
 
             @export(&__aeabi_memcpy, .{ .name = "__aeabi_memcpy", .linkage = common.linkage, .visibility = common.visibility });
             @export(&__aeabi_memcpy4, .{ .name = "__aeabi_memcpy4", .linkage = common.linkage, .visibility = common.visibility });

lib/compiler_rt/aulldiv.zig

@@ -8,7 +8,7 @@ const common = @import("common.zig");
 pub const panic = common.panic;
 
 comptime {
-    if (arch == .x86 and common.want_windows_msvc_or_itanium_abi and !builtin.link_libc) {
+    if (common.want_windows_x86_msvc_abi) {
         // Don't let LLVM apply the stdcall name mangling on those MSVC builtins
         @export(&_alldiv, .{ .name = "\x01__alldiv", .linkage = common.linkage, .visibility = common.visibility });
         @export(&_aulldiv, .{ .name = "\x01__aulldiv", .linkage = common.linkage, .visibility = common.visibility });

lib/compiler_rt/aullrem.zig

@@ -8,7 +8,7 @@ const common = @import("common.zig");
 pub const panic = common.panic;
 
 comptime {
-    if (arch == .x86 and common.want_windows_msvc_or_itanium_abi and !builtin.link_libc) {
+    if (common.want_windows_x86_msvc_abi) {
         // Don't let LLVM apply the stdcall name mangling on those MSVC builtins
         @export(&_allrem, .{ .name = "\x01__allrem", .linkage = common.linkage, .visibility = common.visibility });
         @export(&_aullrem, .{ .name = "\x01__aullrem", .linkage = common.linkage, .visibility = common.visibility });

lib/compiler_rt/common.zig

@@ -48,13 +48,30 @@ pub const want_aeabi = switch (builtin.abi) {
     else => false,
 };
 
-/// These functions are provided by libc when targeting MSVC, but not MinGW.
+/// These functions are required on Windows on ARM. They are provided by MSVC libc, but in libc-less
-// Temporarily used for thumb-uefi until https://github.com/ziglang/zig/issues/21630 is addressed.
+/// builds or when linking MinGW libc they are our responsibility.
-pub const want_windows_arm_abi = builtin.cpu.arch.isArm() and (builtin.os.tag == .windows or builtin.os.tag == .uefi) and (builtin.abi.isGnu() or !builtin.link_libc);
+/// Temporarily used for thumb-uefi until https://github.com/ziglang/zig/issues/21630 is addressed.
+pub const want_windows_arm_abi = e: {
+    if (!builtin.cpu.arch.isArm()) break :e false;
+    switch (builtin.os.tag) {
+        .windows, .uefi => {},
+        else => break :e false,
+    }
+    // The ABI is needed, but it's only our reponsibility if libc won't provide it.
+    break :e builtin.abi.isGnu() or !builtin.link_libc;
+};
 
-pub const want_windows_msvc_or_itanium_abi = switch (builtin.abi) {
+/// These functions are required by on Windows on x86 on some ABIs. They are provided by MSVC libc,
-    .none, .msvc, .itanium => builtin.os.tag == .windows,
+/// but in libc-less builds they are our responsibility.
-    else => false,
+pub const want_windows_x86_msvc_abi = e: {
+    if (builtin.cpu.arch != .x86) break :e false;
+    if (builtin.os.tag != .windows) break :e false;
+    switch (builtin.abi) {
+        .none, .msvc, .itanium => {},
+        else => break :e false,
+    }
+    // The ABI is needed, but it's only our responsibility if libc won't provide it.
+    break :e !builtin.link_libc;
 };
 
 pub const want_ppc_abi = builtin.cpu.arch.isPowerPC();

lib/compiler_rt/fixdfdi.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_d2lz, .{ .name = "__aeabi_d2lz", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__fixdfdi, .{ .name = if (common.want_windows_arm_abi) "__dtoi64" else "__fixdfdi", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__fixdfdi, .{ .name = "__dtoi64", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__fixdfdi, .{ .name = "__fixdfdi", .linkage = common.linkage, .visibility = common.visibility });
     }
 }
 

lib/compiler_rt/fixsfdi.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_f2lz, .{ .name = "__aeabi_f2lz", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__fixsfdi, .{ .name = if (common.want_windows_arm_abi) "__stoi64" else "__fixsfdi", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__fixsfdi, .{ .name = "__stoi64", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__fixsfdi, .{ .name = "__fixsfdi", .linkage = common.linkage, .visibility = common.visibility });
     }
 }
 

lib/compiler_rt/fixunsdfdi.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_d2ulz, .{ .name = "__aeabi_d2ulz", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__fixunsdfdi, .{ .name = if (common.want_windows_arm_abi) "__dtou64" else "__fixunsdfdi", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__fixunsdfdi, .{ .name = "__dtou64", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__fixunsdfdi, .{ .name = "__fixunsdfdi", .linkage = common.linkage, .visibility = common.visibility });
     }
 }
 

lib/compiler_rt/fixunssfdi.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_f2ulz, .{ .name = "__aeabi_f2ulz", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__fixunssfdi, .{ .name = if (common.want_windows_arm_abi) "__stou64" else "__fixunssfdi", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__fixunssfdi, .{ .name = "__stou64", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__fixunssfdi, .{ .name = "__fixunssfdi", .linkage = common.linkage, .visibility = common.visibility });
     }
 }
 

lib/compiler_rt/floatdidf.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_l2d, .{ .name = "__aeabi_l2d", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__floatdidf, .{ .name = if (common.want_windows_arm_abi) "__i64tod" else "__floatdidf", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__floatdidf, .{ .name = "__i64tod", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__floatdidf, .{ .name = "__floatdidf", .linkage = common.linkage, .visibility = common.visibility });
     }
 }
 

lib/compiler_rt/floatdisf.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_l2f, .{ .name = "__aeabi_l2f", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__floatdisf, .{ .name = if (common.want_windows_arm_abi) "__i64tos" else "__floatdisf", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__floatdisf, .{ .name = "__i64tos", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__floatdisf, .{ .name = "__floatdisf", .linkage = common.linkage, .visibility = common.visibility });
     }
 }
 

lib/compiler_rt/floatundidf.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_ul2d, .{ .name = "__aeabi_ul2d", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__floatundidf, .{ .name = if (common.want_windows_arm_abi) "__u64tod" else "__floatundidf", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__floatundidf, .{ .name = "__u64tod", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__floatundidf, .{ .name = "__floatundidf", .linkage = common.linkage, .visibility = common.visibility });
     }
 }
 

lib/compiler_rt/floatundisf.zig

@@ -8,7 +8,10 @@ comptime {
     if (common.want_aeabi) {
         @export(&__aeabi_ul2f, .{ .name = "__aeabi_ul2f", .linkage = common.linkage, .visibility = common.visibility });
     } else {
-        @export(&__floatundisf, .{ .name = if (common.want_windows_arm_abi) "__u64tos" else "__floatundisf", .linkage = common.linkage, .visibility = common.visibility });
+        if (common.want_windows_arm_abi) {
+            @export(&__floatundisf, .{ .name = "__u64tos", .linkage = common.linkage, .visibility = common.visibility });
+        }
+        @export(&__floatundisf, .{ .name = "__floatundisf", .linkage = common.linkage, .visibility = common.visibility });
     }
 }