zig

commit 6986d2aca900bdda30f541baf9b06fb29688fe97 (tree)
parent bc69cb9b106cbb0748b960c10b7cf66d0c5fd28e
Author: Andrew Kelley <andrew@ziglang.org>
Date:   Wed,  1 May 2024 14:39:24 -0700

x86_64 sysv C ABI: fix f128 param and return types

Clang 17 passed struct{f128} parameters using rdi and rax, while Clang
18 matches GCC 13.2 behavior, passing them using xmm0.

This commit makes Zig's LLVM backend match Clang 18 and GCC 13.2. The
commit deletes a hack in x86_64/abi.zig which miscategorized f128 as
"memory" which obviously disagreed with the spec.

Diffstat:
M
src/arch/x86_64/CodeGen.zig
 | 
2
+-
M
src/arch/x86_64/abi.zig
 | 
4
----
M
src/codegen/llvm.zig
 | 
20
++++++++++++++++++--

3 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/src/arch/x86_64/CodeGen.zig b/src/arch/x86_64/CodeGen.zig
@@ -14318,7 +14318,7 @@ fn moveStrategy(self: *Self, ty: Type, class: Register.Class, aligned: bool) !Mo
             else => {
                 const classes = mem.sliceTo(&abi.classifySystemV(ty, mod, self.target.*, .other), .none);
                 assert(std.mem.indexOfNone(abi.Class, classes, &.{
-                    .integer, .sse, .memory, .float, .float_combine,
+                    .integer, .sse, .sseup, .memory, .float, .float_combine,
                 }) == null);
                 const abi_size = ty.abiSize(mod);
                 if (abi_size < 4 or
diff --git a/src/arch/x86_64/abi.zig b/src/arch/x86_64/abi.zig
@@ -170,10 +170,6 @@ pub fn classifySystemV(ty: Type, zcu: *Zcu, target: std.Target, ctx: Context) [8
                 // "Arguments of types __float128, _Decimal128 and __m128 are
                 // split into two halves.  The least significant ones belong
                 // to class SSE, the most significant one to class SSEUP."
-                if (ctx == .field) {
-                    result[0] = .memory;
-                    return result;
-                }
                 result[0] = .sse;
                 result[1] = .sseup;
                 return result;
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
@@ -11167,10 +11167,18 @@ fn lowerSystemVFnRetTy(o: *Object, fn_info: InternPool.Key.FuncType) Allocator.E
                 types_buffer[types_index] = .i64;
                 types_index += 1;
             },
-            .sse, .sseup => {
+            .sse => {
                 types_buffer[types_index] = .double;
                 types_index += 1;
             },
+            .sseup => {
+                if (types_buffer[types_index - 1] == .double) {
+                    types_buffer[types_index - 1] = .fp128;
+                } else {
+                    types_buffer[types_index] = .double;
+                    types_index += 1;
+                }
+            },
             .float => {
                 types_buffer[types_index] = .float;
                 types_index += 1;
@@ -11454,10 +11462,18 @@ const ParamTypeIterator = struct {
                     types_buffer[types_index] = .i64;
                     types_index += 1;
                 },
-                .sse, .sseup => {
+                .sse => {
                     types_buffer[types_index] = .double;
                     types_index += 1;
                 },
+                .sseup => {
+                    if (types_buffer[types_index - 1] == .double) {
+                        types_buffer[types_index - 1] = .fp128;
+                    } else {
+                        types_buffer[types_index] = .double;
+                        types_index += 1;
+                    }
+                },
                 .float => {
                     types_buffer[types_index] = .float;
                     types_index += 1;