From a69f55a7cc3980f4d4dfcce6cb9d21a597975c7f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Mon, 19 Aug 2024 13:25:08 +0200
Subject: [PATCH] std.{coff,elf}: Remove the {MachineType,EM}.toTargetCpuArch()
 functions.

These are fundamentally incapable of producing accurate information for reasons
I've laid out in #20771. Since our only use of these functions is to check that
object files have the correct machine type, and since #21020 made
`std.Target.to{Coff,Elf}Machine()` more accurate, just switch these checks over
to that and compare the machine type tags instead.

Closes #20771.
---
 lib/std/coff.zig              | 17 ----------------
 lib/std/elf.zig               | 38 -----------------------------------
 src/link/Elf/Object.zig       |  8 ++++----
 src/link/Elf/SharedObject.zig |  8 ++++----
 test/link/elf.zig             |  2 +-
 5 files changed, 9 insertions(+), 64 deletions(-)

diff --git a/lib/std/coff.zig b/lib/std/coff.zig
index ca05ce3cf9..da7dc0bcda 100644
--- a/lib/std/coff.zig
+++ b/lib/std/coff.zig
@@ -1060,23 +1060,6 @@ pub const MachineType = enum(u16) {
     WCEMIPSV2 = 0x169,
 
     _,
-
-    pub fn toTargetCpuArch(machine_type: MachineType) ?std.Target.Cpu.Arch {
-        return switch (machine_type) {
-            .ARM => .arm,
-            .POWERPC => .powerpc,
-            .RISCV32 => .riscv32,
-            .THUMB => .thumb,
-            .I386 => .x86,
-            .ARM64 => .aarch64,
-            .RISCV64 => .riscv64,
-            .X64 => .x86_64,
-            .LOONGARCH32 => .loongarch32,
-            .LOONGARCH64 => .loongarch64,
-            // there's cases we don't (yet) handle
-            else => null,
-        };
-    }
 };
 
 pub const CoffError = error{
diff --git a/lib/std/elf.zig b/lib/std/elf.zig
index af3f1813e2..aefaca4bef 100644
--- a/lib/std/elf.zig
+++ b/lib/std/elf.zig
@@ -1646,44 +1646,6 @@ pub const EM = enum(u16) {
     FRV = 0x5441,
 
     _,
-
-    pub fn toTargetCpuArch(em: EM) ?std.Target.Cpu.Arch {
-        return switch (em) {
-            .AVR => .avr,
-            .MSP430 => .msp430,
-            .ARC => .arc,
-            .ARM => .arm,
-            .HEXAGON => .hexagon,
-            .@"68K" => .m68k,
-            .MIPS => .mips,
-            .MIPS_RS3_LE => .mipsel,
-            .PPC => .powerpc,
-            .SPARC => .sparc,
-            .@"386" => .x86,
-            .XCORE => .xcore,
-            .CSR_KALIMBA => .kalimba,
-            .LANAI => .lanai,
-            .AARCH64 => .aarch64,
-            .PPC64 => .powerpc64,
-            .RISCV => .riscv64,
-            .X86_64 => .x86_64,
-            .BPF => .bpfel,
-            .SPARCV9 => .sparc64,
-            .S390 => .s390x,
-            .SPU_2 => .spu_2,
-            // FIXME:
-            // No support for .loongarch32 yet so it is safe to assume we are on .loongarch64.
-            //
-            // However, when e_machine is .LOONGARCH, we should check
-            // ei_class's value to decide the CPU architecture.
-            // - ELFCLASS32 => .loongarch32
-            // - ELFCLASS64 => .loongarch64
-            .LOONGARCH => .loongarch64,
-            // there's many cases we don't (yet) handle, or will never have a
-            // zig target cpu arch equivalent (such as null).
-            else => null,
-        };
-    }
 };
 
 pub const GRP_COMDAT = 1;
diff --git a/src/link/Elf/Object.zig b/src/link/Elf/Object.zig
index a6f9c4ac18..d329218b8d 100644
--- a/src/link/Elf/Object.zig
+++ b/src/link/Elf/Object.zig
@@ -105,12 +105,12 @@ fn parseCommon(self: *Object, allocator: Allocator, handle: std.fs.File, elf_fil
     defer allocator.free(header_buffer);
     self.header = @as(*align(1) const elf.Elf64_Ehdr, @ptrCast(header_buffer)).*;
 
-    const target = elf_file.base.comp.root_mod.resolved_target.result;
-    if (target.cpu.arch != self.header.?.e_machine.toTargetCpuArch().?) {
+    const em = elf_file.base.comp.root_mod.resolved_target.result.toElfMachine();
+    if (em != self.header.?.e_machine) {
         try elf_file.reportParseError2(
             self.index,
-            "invalid cpu architecture: {s}",
-            .{@tagName(self.header.?.e_machine.toTargetCpuArch().?)},
+            "invalid ELF machine type: {s}",
+            .{@tagName(self.header.?.e_machine)},
         );
         return error.InvalidCpuArch;
     }
diff --git a/src/link/Elf/SharedObject.zig b/src/link/Elf/SharedObject.zig
index b33853d23c..7fdf9116b5 100644
--- a/src/link/Elf/SharedObject.zig
+++ b/src/link/Elf/SharedObject.zig
@@ -56,12 +56,12 @@ pub fn parse(self: *SharedObject, elf_file: *Elf, handle: std.fs.File) !void {
     defer gpa.free(header_buffer);
     self.header = @as(*align(1) const elf.Elf64_Ehdr, @ptrCast(header_buffer)).*;
 
-    const target = elf_file.base.comp.root_mod.resolved_target.result;
-    if (target.cpu.arch != self.header.?.e_machine.toTargetCpuArch().?) {
+    const em = elf_file.base.comp.root_mod.resolved_target.result.toElfMachine();
+    if (em != self.header.?.e_machine) {
         try elf_file.reportParseError2(
             self.index,
-            "invalid cpu architecture: {s}",
-            .{@tagName(self.header.?.e_machine.toTargetCpuArch().?)},
+            "invalid ELF machine type: {s}",
+            .{@tagName(self.header.?.e_machine)},
         );
         return error.InvalidCpuArch;
     }
diff --git a/test/link/elf.zig b/test/link/elf.zig
index 98253811b2..6abf596ab7 100644
--- a/test/link/elf.zig
+++ b/test/link/elf.zig
@@ -2257,7 +2257,7 @@ fn testMismatchedCpuArchitectureError(b: *Build, opts: Options) *Step {
     exe.linkLibC();
 
     expectLinkErrors(exe, test_step, .{ .exact = &.{
-        "invalid cpu architecture: aarch64",
+        "invalid ELF machine type: AARCH64",
         "note: while parsing /?/a.o",
     } });