zig

commit 30ef0336932cb2ec866a082b9b4584d08d179a55 (tree)
parent e4092d44426a471ee6097fae24069c72cffdc22a
Author: Andrew Kelley <andrew@ziglang.org>
Date:   Fri, 17 Jun 2022 19:25:06 -0700

compiler-rt: fix logic for choosing `__gnu_{f2h,h2f}_ieee`

wasm32-wasi-musl wants the standard symbol names however Linux requires
the `__gnu_*` flavors. I did not find any authoritative source on what
decides which symbol flavors to use. If we run into more trouble in the
future we can go back to having both.

Diffstat:
M
lib/compiler_rt/common.zig
 | 
37
++++++++++++++++++++++++++++++-------
M
lib/compiler_rt/extendhfsf2.zig
 | 
2
+-
M
lib/compiler_rt/truncsfhf2.zig
 | 
2
+-

3 files changed, 32 insertions(+), 9 deletions(-)
diff --git a/lib/compiler_rt/common.zig b/lib/compiler_rt/common.zig
@@ -1,7 +1,5 @@
 const std = @import("std");
 const builtin = @import("builtin");
-const math = std.math;
-const is_test = builtin.is_test;
 
 pub const linkage: std.builtin.GlobalLinkage = if (builtin.is_test) .Internal else .Weak;
 pub const want_aeabi = switch (builtin.abi) {
@@ -18,19 +16,44 @@ pub const want_aeabi = switch (builtin.abi) {
     else => false,
 };
 pub const want_ppc_abi = builtin.cpu.arch.isPPC() or builtin.cpu.arch.isPPC64();
-pub const want_msvc_abi = builtin.abi == .msvc;
-/// Example symbols:
+
+/// This governs whether to use these symbol names for f16/f32 conversions
+/// rather than the standard names:
 /// * __gnu_f2h_ieee
 /// * __gnu_h2f_ieee
-pub const want_gnu_abi = builtin.abi.isGnu() or builtin.abi.isMusl();
+/// Known correct configurations:
+///   x86_64-freestanding-none => true
+///   x86_64-linux-none => true
+///   x86_64-linux-gnu => true
+///   x86_64-linux-musl => true
+///   x86_64-linux-eabi => true
+///   arm-linux-musleabihf => true
+///   arm-linux-gnueabihf => true
+///   arm-linux-eabihf => false
+///   wasm32-wasi-musl => false
+///   wasm32-freestanding-none => false
+///   x86_64-windows-gnu => true
+///   x86_64-windows-msvc => true
+///   any-macos-any => doesn't matter; libSystem has both symbol flavors
+pub const gnu_f16_abi = switch (builtin.cpu.arch) {
+    .wasm32, .wasm64 => false,
+
+    .arm, .armeb, .thumb, .thumbeb => switch (builtin.abi) {
+        .eabi, .eabihf => false,
+        else => true,
+    },
+
+    else => true,
+};
+
 pub const want_sparc_abi = builtin.cpu.arch.isSPARC();
 
 // Avoid dragging in the runtime safety mechanisms into this .o file,
 // unless we're trying to test compiler-rt.
 pub fn panic(msg: []const u8, error_return_trace: ?*std.builtin.StackTrace) noreturn {
     _ = error_return_trace;
-    @setCold(true);
-    if (is_test) {
+    if (builtin.is_test) {
+        @setCold(true);
         std.debug.panic("{s}", .{msg});
     } else {
         unreachable;
diff --git a/lib/compiler_rt/extendhfsf2.zig b/lib/compiler_rt/extendhfsf2.zig
@@ -4,7 +4,7 @@ const extendf = @import("./extendf.zig").extendf;
 pub const panic = common.panic;
 
 comptime {
-    if (common.want_gnu_abi) {
+    if (common.gnu_f16_abi) {
         @export(__gnu_h2f_ieee, .{ .name = "__gnu_h2f_ieee", .linkage = common.linkage });
     } else if (common.want_aeabi) {
         @export(__aeabi_h2f, .{ .name = "__aeabi_h2f", .linkage = common.linkage });
diff --git a/lib/compiler_rt/truncsfhf2.zig b/lib/compiler_rt/truncsfhf2.zig
@@ -4,7 +4,7 @@ const truncf = @import("./truncf.zig").truncf;
 pub const panic = common.panic;
 
 comptime {
-    if (common.want_gnu_abi) {
+    if (common.gnu_f16_abi) {
         @export(__gnu_f2h_ieee, .{ .name = "__gnu_f2h_ieee", .linkage = common.linkage });
     } else if (common.want_aeabi) {
         @export(__aeabi_f2h, .{ .name = "__aeabi_f2h", .linkage = common.linkage });