From ef24de24a82fe681581cc130f342363c47c0969a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 7 Jun 2024 07:48:48 +0200 Subject: Merging upstream version 1.75.0+dfsg1. Signed-off-by: Daniel Baumann --- .../rustc_target/src/spec/i686_unknown_uefi.rs | 89 ---------------------- 1 file changed, 89 deletions(-) delete mode 100644 compiler/rustc_target/src/spec/i686_unknown_uefi.rs (limited to 'compiler/rustc_target/src/spec/i686_unknown_uefi.rs') diff --git a/compiler/rustc_target/src/spec/i686_unknown_uefi.rs b/compiler/rustc_target/src/spec/i686_unknown_uefi.rs deleted file mode 100644 index a2e42c5e6..000000000 --- a/compiler/rustc_target/src/spec/i686_unknown_uefi.rs +++ /dev/null @@ -1,89 +0,0 @@ -// This defines the ia32 target for UEFI systems as described in the UEFI specification. See the -// uefi-base module for generic UEFI options. On ia32 systems -// UEFI systems always run in protected-mode, have the interrupt-controller pre-configured and -// force a single-CPU execution. -// The cdecl ABI is used. It differs from the stdcall or fastcall ABI. -// "i686-unknown-windows" is used to get the minimal subset of windows-specific features. - -use crate::spec::Target; - -pub fn target() -> Target { - let mut base = super::uefi_msvc_base::opts(); - base.cpu = "pentium4".into(); - base.max_atomic_width = Some(64); - - // We disable MMX and SSE for now, even though UEFI allows using them. Problem is, you have to - // enable these CPU features explicitly before their first use, otherwise their instructions - // will trigger an exception. Rust does not inject any code that enables AVX/MMX/SSE - // instruction sets, so this must be done by the firmware. However, existing firmware is known - // to leave these uninitialized, thus triggering exceptions if we make use of them. Which is - // why we avoid them and instead use soft-floats. This is also what GRUB and friends did so - // far. - // If you initialize FP units yourself, you can override these flags with custom linker - // arguments, thus giving you access to full MMX/SSE acceleration. - base.features = "-mmx,-sse,+soft-float".into(); - - // Use -GNU here, because of the reason below: - // Background and Problem: - // If we use i686-unknown-windows, the LLVM IA32 MSVC generates compiler intrinsic - // _alldiv, _aulldiv, _allrem, _aullrem, _allmul, which will cause undefined symbol. - // A real issue is __aulldiv() is referred by __udivdi3() - udivmod_inner!(), from - // https://github.com/rust-lang-nursery/compiler-builtins. - // As result, rust-lld generates link error finally. - // Root-cause: - // In rust\src\llvm-project\llvm\lib\Target\X86\X86ISelLowering.cpp, - // we have below code to use MSVC intrinsics. It assumes MSVC target - // will link MSVC library. But that is NOT true in UEFI environment. - // UEFI does not link any MSVC or GCC standard library. - // if (Subtarget.isTargetKnownWindowsMSVC() || - // Subtarget.isTargetWindowsItanium()) { - // // Setup Windows compiler runtime calls. - // setLibcallName(RTLIB::SDIV_I64, "_alldiv"); - // setLibcallName(RTLIB::UDIV_I64, "_aulldiv"); - // setLibcallName(RTLIB::SREM_I64, "_allrem"); - // setLibcallName(RTLIB::UREM_I64, "_aullrem"); - // setLibcallName(RTLIB::MUL_I64, "_allmul"); - // setLibcallCallingConv(RTLIB::SDIV_I64, CallingConv::X86_StdCall); - // setLibcallCallingConv(RTLIB::UDIV_I64, CallingConv::X86_StdCall); - // setLibcallCallingConv(RTLIB::SREM_I64, CallingConv::X86_StdCall); - // setLibcallCallingConv(RTLIB::UREM_I64, CallingConv::X86_StdCall); - // setLibcallCallingConv(RTLIB::MUL_I64, CallingConv::X86_StdCall); - // } - // The compiler intrinsics should be implemented by compiler-builtins. - // Unfortunately, compiler-builtins has not provided those intrinsics yet. Such as: - // i386/divdi3.S - // i386/lshrdi3.S - // i386/moddi3.S - // i386/muldi3.S - // i386/udivdi3.S - // i386/umoddi3.S - // Possible solution: - // 1. Eliminate Intrinsics generation. - // 1.1 Choose different target to bypass isTargetKnownWindowsMSVC(). - // 1.2 Remove the "Setup Windows compiler runtime calls" in LLVM - // 2. Implement Intrinsics. - // We evaluated all options. - // #2 is hard because we need implement the intrinsics (_aulldiv) generated - // from the other intrinsics (__udivdi3) implementation with the same - // functionality (udivmod_inner). If we let _aulldiv() call udivmod_inner!(), - // then we are in loop. We may have to find another way to implement udivmod_inner!(). - // #1.2 may break the existing usage. - // #1.1 seems the simplest solution today. - // The IA32 -gnu calling convention is same as the one defined in UEFI specification. - // It uses cdecl, EAX/ECX/EDX as volatile register, and EAX/EDX as return value. - // We also checked the LLVM X86TargetLowering, the differences between -gnu and -msvc - // is fmodf(f32), longjmp() and TLS. None of them impacts the UEFI code. - // As a result, we choose -gnu for i686 version before those intrinsics are implemented in - // compiler-builtins. After compiler-builtins implements all required intrinsics, we may - // remove -gnu and use the default one. - Target { - llvm_target: "i686-unknown-windows-gnu".into(), - pointer_width: 32, - data_layout: "e-m:x-p:32:32-p270:32:32-p271:32:32-p272:64:64-\ - i64:64-f80:32-n8:16:32-a:0:32-S32" - .into(), - arch: "x86".into(), - - options: base, - } -} -- cgit v1.2.3