diff options
Diffstat (limited to 'compiler/rustc_codegen_gcc/src/asm.rs')
| -rw-r--r-- | compiler/rustc_codegen_gcc/src/asm.rs | 289 |
1 files changed, 162 insertions, 127 deletions
diff --git a/compiler/rustc_codegen_gcc/src/asm.rs b/compiler/rustc_codegen_gcc/src/asm.rs index 415f8affab9..dbdf37ee6c9 100644 --- a/compiler/rustc_codegen_gcc/src/asm.rs +++ b/compiler/rustc_codegen_gcc/src/asm.rs @@ -36,7 +36,8 @@ use crate::type_of::LayoutGccExt; // // 3. Clobbers. GCC has a separate list of clobbers, and clobbers don't have indexes. // Contrary, Rust expresses clobbers through "out" operands that aren't tied to -// a variable (`_`), and such "clobbers" do have index. +// a variable (`_`), and such "clobbers" do have index. Input operands cannot also +// be clobbered. // // 4. Furthermore, GCC Extended Asm does not support explicit register constraints // (like `out("eax")`) directly, offering so-called "local register variables" @@ -161,6 +162,16 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> { // Also, we don't emit any asm operands immediately; we save them to // the one of the buffers to be emitted later. + let mut input_registers = vec![]; + + for op in rust_operands { + if let InlineAsmOperandRef::In { reg, .. } = *op { + if let ConstraintOrRegister::Register(reg_name) = reg_to_gcc(reg) { + input_registers.push(reg_name); + } + } + } + // 1. Normal variables (and saving operands to buffers). for (rust_idx, op) in rust_operands.iter().enumerate() { match *op { @@ -183,25 +194,39 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> { continue; } (Register(reg_name), None) => { - // `clobber_abi` can add lots of clobbers that are not supported by the target, - // such as AVX-512 registers, so we just ignore unsupported registers - let is_target_supported = - reg.reg_class().supported_types(asm_arch, true).iter().any( - |&(_, feature)| { - if let Some(feature) = feature { - self.tcx - .asm_target_features(instance.def_id()) - .contains(&feature) - } else { - true // Register class is unconditionally supported - } - }, - ); - - if is_target_supported && !clobbers.contains(®_name) { - clobbers.push(reg_name); + if input_registers.contains(®_name) { + // the `clobber_abi` operand is converted into a series of + // `lateout("reg") _` operands. Of course, a user could also + // explicitly define such an output operand. + // + // GCC does not allow input registers to be clobbered, so if this out register + // is also used as an in register, do not add it to the clobbers list. + // it will be treated as a lateout register with `out_place: None` + if !late { + bug!("input registers can only be used as lateout regisers"); + } + ("r", dummy_output_type(self.cx, reg.reg_class())) + } else { + // `clobber_abi` can add lots of clobbers that are not supported by the target, + // such as AVX-512 registers, so we just ignore unsupported registers + let is_target_supported = + reg.reg_class().supported_types(asm_arch, true).iter().any( + |&(_, feature)| { + if let Some(feature) = feature { + self.tcx + .asm_target_features(instance.def_id()) + .contains(&feature) + } else { + true // Register class is unconditionally supported + } + }, + ); + + if is_target_supported && !clobbers.contains(®_name) { + clobbers.push(reg_name); + } + continue; } - continue; } }; @@ -230,13 +255,10 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> { } InlineAsmOperandRef::InOut { reg, late, in_value, out_place } => { - let constraint = - if let ConstraintOrRegister::Constraint(constraint) = reg_to_gcc(reg) { - constraint - } else { - // left for the next pass - continue; - }; + let ConstraintOrRegister::Constraint(constraint) = reg_to_gcc(reg) else { + // left for the next pass + continue; + }; // Rustc frontend guarantees that input and output types are "compatible", // so we can just use input var's type for the output variable. @@ -589,114 +611,127 @@ fn estimate_template_length( } /// Converts a register class to a GCC constraint code. -fn reg_to_gcc(reg: InlineAsmRegOrRegClass) -> ConstraintOrRegister { - let constraint = match reg { - // For vector registers LLVM wants the register name to match the type size. +fn reg_to_gcc(reg_or_reg_class: InlineAsmRegOrRegClass) -> ConstraintOrRegister { + match reg_or_reg_class { InlineAsmRegOrRegClass::Reg(reg) => { - match reg { - InlineAsmReg::X86(_) => { - // TODO(antoyo): add support for vector register. - // - // // For explicit registers, we have to create a register variable: https://stackoverflow.com/a/31774784/389119 - return ConstraintOrRegister::Register(match reg.name() { - // Some of registers' names does not map 1-1 from rust to gcc - "st(0)" => "st", + ConstraintOrRegister::Register(explicit_reg_to_gcc(reg)) + } + InlineAsmRegOrRegClass::RegClass(reg_class) => { + ConstraintOrRegister::Constraint(reg_class_to_gcc(reg_class)) + } + } +} - name => name, - }); +fn explicit_reg_to_gcc(reg: InlineAsmReg) -> &'static str { + // For explicit registers, we have to create a register variable: https://stackoverflow.com/a/31774784/389119 + match reg { + InlineAsmReg::X86(reg) => { + // TODO(antoyo): add support for vector register. + match reg.reg_class() { + X86InlineAsmRegClass::reg_byte => { + // GCC does not support the `b` suffix, so we just strip it + // see https://github.com/rust-lang/rustc_codegen_gcc/issues/485 + reg.name().trim_end_matches('b') } + _ => match reg.name() { + // Some of registers' names does not map 1-1 from rust to gcc + "st(0)" => "st", - _ => unimplemented!(), + name => name, + }, } } - // They can be retrieved from https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html - InlineAsmRegOrRegClass::RegClass(reg) => match reg { - InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => "r", - InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg) => "w", - InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => "x", - InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => { - unreachable!("clobber-only") - } - InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg) - | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low16) - | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8) - | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg_low16) - | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low8) - | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) - | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg) - | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg) => "t", - InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_upper) => "d", - InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_pair) => "r", - InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_iw) => "w", - InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => "e", - InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::wreg) => "w", - InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::preg) => { - unreachable!("clobber-only") - } - InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::freg) => "f", - InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_addr) => "a", - InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_data) => "d", - InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::freg) => "f", - InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg) => "d", // more specific than "r" - InlineAsmRegClass::Mips(MipsInlineAsmRegClass::freg) => "f", - InlineAsmRegClass::Msp430(Msp430InlineAsmRegClass::reg) => "r", - // https://github.com/gcc-mirror/gcc/blob/master/gcc/config/nvptx/nvptx.md -> look for - // "define_constraint". - InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg16) => "h", - InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg32) => "r", - InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg64) => "l", - - InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg_nonzero) => "b", - InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::freg) => "f", - InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::vreg) => "v", - InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::cr) - | InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::xer) => { - unreachable!("clobber-only") - } - InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => "f", - InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => { - unreachable!("clobber-only") - } - InlineAsmRegClass::X86(X86InlineAsmRegClass::reg) => "r", - InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => "Q", - InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => "q", - InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg) - | InlineAsmRegClass::X86(X86InlineAsmRegClass::ymm_reg) => "x", - InlineAsmRegClass::X86(X86InlineAsmRegClass::zmm_reg) => "v", - InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => "Yk", - InlineAsmRegClass::X86( - X86InlineAsmRegClass::kreg0 - | X86InlineAsmRegClass::x87_reg - | X86InlineAsmRegClass::mmx_reg - | X86InlineAsmRegClass::tmm_reg, - ) => unreachable!("clobber-only"), - InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => { - bug!("GCC backend does not support SPIR-V") - } - InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => "r", - InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg_addr) => "a", - InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => "f", - InlineAsmRegClass::S390x(S390xInlineAsmRegClass::vreg) => "v", - InlineAsmRegClass::S390x(S390xInlineAsmRegClass::areg) => { - unreachable!("clobber-only") - } - InlineAsmRegClass::Sparc(SparcInlineAsmRegClass::reg) => "r", - InlineAsmRegClass::Sparc(SparcInlineAsmRegClass::yreg) => unreachable!("clobber-only"), - InlineAsmRegClass::Err => unreachable!(), - }, - }; - ConstraintOrRegister::Constraint(constraint) + _ => unimplemented!(), + } +} + +/// They can be retrieved from https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html +fn reg_class_to_gcc(reg_class: InlineAsmRegClass) -> &'static str { + match reg_class { + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => "r", + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg) => "w", + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => "x", + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low16) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg_low16) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low8) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg) => "t", + InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_upper) => "d", + InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_pair) => "r", + InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_iw) => "w", + InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => "e", + InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::wreg) => "w", + InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::preg) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::freg) => "f", + InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_addr) => "a", + InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_data) => "d", + InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::freg) => "f", + InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg) => "d", // more specific than "r" + InlineAsmRegClass::Mips(MipsInlineAsmRegClass::freg) => "f", + InlineAsmRegClass::Msp430(Msp430InlineAsmRegClass::reg) => "r", + // https://github.com/gcc-mirror/gcc/blob/master/gcc/config/nvptx/nvptx.md -> look for + // "define_constraint". + InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg16) => "h", + InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg32) => "r", + InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg64) => "l", + + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg_nonzero) => "b", + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::freg) => "f", + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::vreg) => "v", + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::cr) + | InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::xer) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => "f", + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::X86(X86InlineAsmRegClass::reg) => "r", + InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => "Q", + InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => "q", + InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg) + | InlineAsmRegClass::X86(X86InlineAsmRegClass::ymm_reg) => "x", + InlineAsmRegClass::X86(X86InlineAsmRegClass::zmm_reg) => "v", + InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => "Yk", + InlineAsmRegClass::X86( + X86InlineAsmRegClass::kreg0 + | X86InlineAsmRegClass::x87_reg + | X86InlineAsmRegClass::mmx_reg + | X86InlineAsmRegClass::tmm_reg, + ) => unreachable!("clobber-only"), + InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => { + bug!("GCC backend does not support SPIR-V") + } + InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => "r", + InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg_addr) => "a", + InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => "f", + InlineAsmRegClass::S390x(S390xInlineAsmRegClass::vreg) => "v", + InlineAsmRegClass::S390x(S390xInlineAsmRegClass::areg) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::Sparc(SparcInlineAsmRegClass::reg) => "r", + InlineAsmRegClass::Sparc(SparcInlineAsmRegClass::yreg) => unreachable!("clobber-only"), + InlineAsmRegClass::Err => unreachable!(), + } } /// Type to use for outputs that are discarded. It doesn't really matter what |