diff options
Diffstat (limited to 'compiler/rustc_codegen_gcc/src/asm.rs')
| -rw-r--r-- | compiler/rustc_codegen_gcc/src/asm.rs | 869 |
1 files changed, 869 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_gcc/src/asm.rs b/compiler/rustc_codegen_gcc/src/asm.rs new file mode 100644 index 00000000000..f3a9ca77a67 --- /dev/null +++ b/compiler/rustc_codegen_gcc/src/asm.rs @@ -0,0 +1,869 @@ +use gccjit::{LValue, RValue, ToRValue, Type}; +use rustc_ast::ast::{InlineAsmOptions, InlineAsmTemplatePiece}; +use rustc_codegen_ssa::mir::operand::OperandValue; +use rustc_codegen_ssa::mir::place::PlaceRef; +use rustc_codegen_ssa::traits::{AsmBuilderMethods, AsmMethods, BaseTypeMethods, BuilderMethods, GlobalAsmOperandRef, InlineAsmOperandRef}; + +use rustc_middle::{bug, ty::Instance}; +use rustc_span::Span; +use rustc_target::asm::*; + +use std::borrow::Cow; + +use crate::builder::Builder; +use crate::context::CodegenCx; +use crate::errors::UnwindingInlineAsm; +use crate::type_of::LayoutGccExt; +use crate::callee::get_fn; + + +// Rust asm! and GCC Extended Asm semantics differ substantially. +// +// 1. Rust asm operands go along as one list of operands. Operands themselves indicate +// if they're "in" or "out". "In" and "out" operands can interleave. One operand can be +// both "in" and "out" (`inout(reg)`). +// +// GCC asm has two different lists for "in" and "out" operands. In terms of gccjit, +// this means that all "out" operands must go before "in" operands. "In" and "out" operands +// cannot interleave. +// +// 2. Operand lists in both Rust and GCC are indexed. Index starts from 0. Indexes are important +// because the asm template refers to operands by index. +// +// Mapping from Rust to GCC index would be 1-1 if it wasn't for... +// +// 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. +// +// 4. Furthermore, GCC Extended Asm does not support explicit register constraints +// (like `out("eax")`) directly, offering so-called "local register variables" +// as a workaround. These variables need to be declared and initialized *before* +// the Extended Asm block but *after* normal local variables +// (see comment in `codegen_inline_asm` for explanation). +// +// With that in mind, let's see how we translate Rust syntax to GCC +// (from now on, `CC` stands for "constraint code"): +// +// * `out(reg_class) var` -> translated to output operand: `"=CC"(var)` +// * `inout(reg_class) var` -> translated to output operand: `"+CC"(var)` +// * `in(reg_class) var` -> translated to input operand: `"CC"(var)` +// +// * `out(reg_class) _` -> translated to one `=r(tmp)`, where "tmp" is a temporary unused variable +// +// * `out("explicit register") _` -> not translated to any operands, register is simply added to clobbers list +// +// * `inout(reg_class) in_var => out_var` -> translated to two operands: +// output: `"=CC"(in_var)` +// input: `"num"(out_var)` where num is the GCC index +// of the corresponding output operand +// +// * `inout(reg_class) in_var => _` -> same as `inout(reg_class) in_var => tmp`, +// where "tmp" is a temporary unused variable +// +// * `out/in/inout("explicit register") var` -> translated to one or two operands as described above +// with `"r"(var)` constraint, +// and one register variable assigned to the desired register. + +const ATT_SYNTAX_INS: &str = ".att_syntax noprefix\n\t"; +const INTEL_SYNTAX_INS: &str = "\n\t.intel_syntax noprefix"; + + +struct AsmOutOperand<'a, 'tcx, 'gcc> { + rust_idx: usize, + constraint: &'a str, + late: bool, + readwrite: bool, + + tmp_var: LValue<'gcc>, + out_place: Option<PlaceRef<'tcx, RValue<'gcc>>> +} + +struct AsmInOperand<'a, 'tcx> { + rust_idx: usize, + constraint: Cow<'a, str>, + val: RValue<'tcx> +} + +impl AsmOutOperand<'_, '_, '_> { + fn to_constraint(&self) -> String { + let mut res = String::with_capacity(self.constraint.len() + self.late as usize + 1); + + let sign = if self.readwrite { '+' } else { '=' }; + res.push(sign); + if !self.late { + res.push('&'); + } + + res.push_str(&self.constraint); + res + } +} + +enum ConstraintOrRegister { + Constraint(&'static str), + Register(&'static str) +} + + +impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> { + fn codegen_inline_asm(&mut self, template: &[InlineAsmTemplatePiece], rust_operands: &[InlineAsmOperandRef<'tcx, Self>], options: InlineAsmOptions, span: &[Span], instance: Instance<'_>, _dest_catch_funclet: Option<(Self::BasicBlock, Self::BasicBlock, Option<&Self::Funclet>)>) { + if options.contains(InlineAsmOptions::MAY_UNWIND) { + self.sess() + .create_err(UnwindingInlineAsm { span: span[0] }) + .emit(); + return; + } + + let asm_arch = self.tcx.sess.asm_arch.unwrap(); + let is_x86 = matches!(asm_arch, InlineAsmArch::X86 | InlineAsmArch::X86_64); + let att_dialect = is_x86 && options.contains(InlineAsmOptions::ATT_SYNTAX); + + // GCC index of an output operand equals its position in the array + let mut outputs = vec![]; + + // GCC index of an input operand equals its position in the array + // added to `outputs.len()` + let mut inputs = vec![]; + + // Clobbers collected from `out("explicit register") _` and `inout("expl_reg") var => _` + let mut clobbers = vec![]; + + // We're trying to preallocate space for the template + let mut constants_len = 0; + + // There are rules we must adhere to if we want GCC to do the right thing: + // + // * Every local variable that the asm block uses as an output must be declared *before* + // the asm block. + // * There must be no instructions whatsoever between the register variables and the asm. + // + // Therefore, the backend must generate the instructions strictly in this order: + // + // 1. Output variables. + // 2. Register variables. + // 3. The asm block. + // + // We also must make sure that no input operands are emitted before output operands. + // + // This is why we work in passes, first emitting local vars, then local register vars. + // Also, we don't emit any asm operands immediately; we save them to + // the one of the buffers to be emitted later. + + // 1. Normal variables (and saving operands to buffers). + for (rust_idx, op) in rust_operands.iter().enumerate() { + match *op { + InlineAsmOperandRef::Out { reg, late, place } => { + use ConstraintOrRegister::*; + + let (constraint, ty) = match (reg_to_gcc(reg), place) { + (Constraint(constraint), Some(place)) => (constraint, place.layout.gcc_type(self.cx)), + // When `reg` is a class and not an explicit register but the out place is not specified, + // we need to create an unused output variable to assign the output to. This var + // needs to be of a type that's "compatible" with the register class, but specific type + // doesn't matter. + (Constraint(constraint), None) => (constraint, dummy_output_type(self.cx, reg.reg_class())), + (Register(_), Some(_)) => { + // left for the next pass + 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).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 + } + }; + + let tmp_var = self.current_func().new_local(None, ty, "output_register"); + outputs.push(AsmOutOperand { + constraint, + rust_idx, + late, + readwrite: false, + tmp_var, + out_place: place + }); + } + + InlineAsmOperandRef::In { reg, value } => { + if let ConstraintOrRegister::Constraint(constraint) = reg_to_gcc(reg) { + inputs.push(AsmInOperand { + constraint: Cow::Borrowed(constraint), + rust_idx, + val: value.immediate() + }); + } + else { + // left for the next pass + continue + } + } + + 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 + }; + + // Rustc frontend guarantees that input and output types are "compatible", + // so we can just use input var's type for the output variable. + // + // This decision is also backed by the fact that LLVM needs in and out + // values to be of *exactly the same type*, not just "compatible". + // I'm not sure if GCC is so picky too, but better safe than sorry. + let ty = in_value.layout.gcc_type(self.cx); + let tmp_var = self.current_func().new_local(None, ty, "output_register"); + + // If the out_place is None (i.e `inout(reg) _` syntax was used), we translate + // it to one "readwrite (+) output variable", otherwise we translate it to two + // "out and tied in" vars as described above. + let readwrite = out_place.is_none(); + outputs.push(AsmOutOperand { + constraint, + rust_idx, + late, + readwrite, + tmp_var, + out_place, + }); + + if !readwrite { + let out_gcc_idx = outputs.len() - 1; + let constraint = Cow::Owned(out_gcc_idx.to_string()); + + inputs.push(AsmInOperand { + constraint, + rust_idx, + val: in_value.immediate() + }); + } + } + + InlineAsmOperandRef::Const { ref string } => { + constants_len += string.len() + att_dialect as usize; + } + + InlineAsmOperandRef::SymFn { instance } => { + // TODO(@Amanieu): Additional mangling is needed on + // some targets to add a leading underscore (Mach-O) + // or byte count suffixes (x86 Windows). + constants_len += self.tcx.symbol_name(instance).name.len(); + } + InlineAsmOperandRef::SymStatic { def_id } => { + // TODO(@Amanieu): Additional mangling is needed on + // some targets to add a leading underscore (Mach-O). + constants_len += self.tcx.symbol_name(Instance::mono(self.tcx, def_id)).name.len(); + } + } + } + + // 2. Register variables. + for (rust_idx, op) in rust_operands.iter().enumerate() { + match *op { + // `out("explicit register") var` + InlineAsmOperandRef::Out { reg, late, place } => { + if let ConstraintOrRegister::Register(reg_name) = reg_to_gcc(reg) { + let out_place = if let Some(place) = place { + place + } + else { + // processed in the previous pass + continue + }; + + let ty = out_place.layout.gcc_type(self.cx); + let tmp_var = self.current_func().new_local(None, ty, "output_register"); + tmp_var.set_register_name(reg_name); + + outputs.push(AsmOutOperand { + constraint: "r".into(), + rust_idx, + late, + readwrite: false, + tmp_var, + out_place: Some(out_place) + }); + } + + // processed in the previous pass + } + + // `in("explicit register") var` + InlineAsmOperandRef::In { reg, value } => { + if let ConstraintOrRegister::Register(reg_name) = reg_to_gcc(reg) { + let ty = value.layout.gcc_type(self.cx); + let reg_var = self.current_func().new_local(None, ty, "input_register"); + reg_var.set_register_name(reg_name); + self.llbb().add_assignment(None, reg_var, value.immediate()); + + inputs.push(AsmInOperand { + constraint: "r".into(), + rust_idx, + val: reg_var.to_rvalue() + }); + } + + // processed in the previous pass + } + + // `inout("explicit register") in_var => out_var` + InlineAsmOperandRef::InOut { reg, late, in_value, out_place } => { + if let ConstraintOrRegister::Register(reg_name) = reg_to_gcc(reg) { + // See explanation in the first pass. + let ty = in_value.layout.gcc_type(self.cx); + let tmp_var = self.current_func().new_local(None, ty, "output_register"); + tmp_var.set_register_name(reg_name); + + outputs.push(AsmOutOperand { + constraint: "r".into(), + rust_idx, + late, + readwrite: false, + tmp_var, + out_place, + }); + + let constraint = Cow::Owned((outputs.len() - 1).to_string()); + inputs.push(AsmInOperand { + constraint, + rust_idx, + val: in_value.immediate() + }); + } + + // processed in the previous pass + } + + InlineAsmOperandRef::SymFn { instance } => { + inputs.push(AsmInOperand { + constraint: "X".into(), + rust_idx, + val: get_fn(self.cx, instance).get_address(None), + }); + } + + InlineAsmOperandRef::SymStatic { def_id } => { + inputs.push(AsmInOperand { + constraint: "X".into(), + rust_idx, + val: self.cx.get_static(def_id).get_address(None), + }); + } + + InlineAsmOperandRef::Const { .. } => { + // processed in the previous pass + } + } + } + + // 3. Build the template string + + let mut template_str = String::with_capacity(estimate_template_length(template, constants_len, att_dialect)); + if att_dialect { + template_str.push_str(ATT_SYNTAX_INS); + } + + for piece in template { + match *piece { + InlineAsmTemplatePiece::String(ref string) => { + for char in string.chars() { + // TODO(antoyo): might also need to escape | if rustc doesn't do it. + let escaped_char = + match char { + '%' => "%%", + '{' => "%{", + '}' => "%}", + _ => { + template_str.push(char); + continue; + }, + }; + template_str.push_str(escaped_char); + } + } + InlineAsmTemplatePiece::Placeholder { operand_idx, modifier, span: _ } => { + let mut push_to_template = |modifier, gcc_idx| { + use std::fmt::Write; + + template_str.push('%'); + if let Some(modifier) = modifier { + template_str.push(modifier); + } + write!(template_str, "{}", gcc_idx).expect("pushing to string failed"); + }; + + match rust_operands[operand_idx] { + InlineAsmOperandRef::Out { reg, .. } => { + let modifier = modifier_to_gcc(asm_arch, reg.reg_class(), modifier); + let gcc_index = outputs.iter() + .position(|op| operand_idx == op.rust_idx) + .expect("wrong rust index"); + push_to_template(modifier, gcc_index); + } + + InlineAsmOperandRef::In { reg, .. } => { + let modifier = modifier_to_gcc(asm_arch, reg.reg_class(), modifier); + let in_gcc_index = inputs.iter() + .position(|op| operand_idx == op.rust_idx) + .expect("wrong rust index"); + let gcc_index = in_gcc_index + outputs.len(); + push_to_template(modifier, gcc_index); + } + + InlineAsmOperandRef::InOut { reg, .. } => { + let modifier = modifier_to_gcc(asm_arch, reg.reg_class(), modifier); + + // The input register is tied to the output, so we can just use the index of the output register + let gcc_index = outputs.iter() + .position(|op| operand_idx == op.rust_idx) + .expect("wrong rust index"); + push_to_template(modifier, gcc_index); + } + + InlineAsmOperandRef::SymFn { instance } => { + // TODO(@Amanieu): Additional mangling is needed on + // some targets to add a leading underscore (Mach-O) + // or byte count suffixes (x86 Windows). + let name = self.tcx.symbol_name(instance).name; + template_str.push_str(name); + } + + InlineAsmOperandRef::SymStatic { def_id } => { + // TODO(@Amanieu): Additional mangling is needed on + // some targets to add a leading underscore (Mach-O). + let instance = Instance::mono(self.tcx, def_id); + let name = self.tcx.symbol_name(instance).name; + template_str.push_str(name); + } + + InlineAsmOperandRef::Const { ref string } => { + template_str.push_str(string); + } + } + } + } + } + + if att_dialect { + template_str.push_str(INTEL_SYNTAX_INS); + } + + // 4. Generate Extended Asm block + + let block = self.llbb(); + let extended_asm = block.add_extended_asm(None, &template_str); + + for op in &outputs { + extended_asm.add_output_operand(None, &op.to_constraint(), op.tmp_var); + } + + for op in &inputs { + extended_asm.add_input_operand(None, &op.constraint, op.val); + } + + for clobber in clobbers.iter() { + extended_asm.add_clobber(clobber); + } + + if !options.contains(InlineAsmOptions::PRESERVES_FLAGS) { + // TODO(@Commeownist): I'm not 100% sure this one clobber is sufficient + // on all architectures. For instance, what about FP stack? + extended_asm.add_clobber("cc"); + } + if !options.contains(InlineAsmOptions::NOMEM) { + extended_asm.add_clobber("memory"); + } + if !options.contains(InlineAsmOptions::PURE) { + extended_asm.set_volatile_flag(true); + } + if !options.contains(InlineAsmOptions::NOSTACK) { + // TODO(@Commeownist): figure out how to align stack + } + if options.contains(InlineAsmOptions::NORETURN) { + let builtin_unreachable = self.context.get_builtin_function("__builtin_unreachable"); + let builtin_unreachable: RValue<'gcc> = unsafe { std::mem::transmute(builtin_unreachable) }; + self.call(self.type_void(), None, None, builtin_unreachable, &[], None); + } + + // Write results to outputs. + // + // We need to do this because: + // 1. Turning `PlaceRef` into `RValue` is error-prone and has nasty edge cases + // (especially with current `rustc_backend_ssa` API). + // 2. Not every output operand has an `out_place`, and it's required by `add_output_operand`. + // + // Instead, we generate a temporary output variable for each output operand, and then this loop, + // generates `out_place = tmp_var;` assignments if out_place exists. + for op in &outputs { + if let Some(place) = op.out_place { + OperandValue::Immediate(op.tmp_var.to_rvalue()).store(self, place); + } + } + } +} + +fn estimate_template_length(template: &[InlineAsmTemplatePiece], constants_len: usize, att_dialect: bool) -> usize { + let len: usize = template.iter().map(|piece| { + match *piece { + InlineAsmTemplatePiece::String(ref string) => { + string.len() + } + InlineAsmTemplatePiece::Placeholder { .. } => { + // '%' + 1 char modifier + 1 char index + 3 + } + } + }) + .sum(); + + // increase it by 5% to account for possible '%' signs that'll be duplicated + // I pulled the number out of blue, but should be fair enough + // as the upper bound + let mut res = (len as f32 * 1.05) as usize + constants_len; + + if att_dialect { + res += INTEL_SYNTAX_INS.len() + ATT_SYNTAX_INS.len(); + } + res +} + +/// 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. + 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", + + name => name, + }); + } + + _ => unimplemented!(), + } + }, + // 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::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::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::freg) => "f", + InlineAsmRegClass::Err => unreachable!(), + } + }; + + ConstraintOrRegister::Constraint(constraint) +} + +/// Type to use for outputs that are discarded. It doesn't really matter what +/// the type is, as long as it is valid for the constraint code. +fn dummy_output_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, reg: InlineAsmRegClass) -> Type<'gcc> { + match reg { + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => unimplemented!(), + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg) + | InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => { + unimplemented!() + } + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg)=> cx.type_i32(), + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg_low16) => cx.type_f32(), + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low16) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low8) => cx.type_f64(), + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) => { + unimplemented!() + } + InlineAsmRegClass::Avr(_) => unimplemented!(), + InlineAsmRegClass::Bpf(_) => unimplemented!(), + InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::freg) => cx.type_f32(), + InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_addr) => cx.type_i32(), + InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_data) => cx.type_i32(), + InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::freg) => cx.type_f32(), + InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::Mips(MipsInlineAsmRegClass::freg) => cx.type_f32(), + InlineAsmRegClass::Msp430(_) => unimplemented!(), + InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg16) => cx.type_i16(), + InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg32) => cx.type_i32(), + InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg64) => cx.type_i64(), + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::reg_nonzero) => cx.type_i32(), + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::freg) => cx.type_f64(), + InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::cr) + | InlineAsmRegClass::PowerPC(PowerPCInlineAsmRegClass::xer) => { + unreachable!("clobber-only") + }, + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => cx.type_f32(), + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => cx.type_f32(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::reg) + | InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => cx.type_i32(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => cx.type_i8(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::mmx_reg) => unimplemented!(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg) + | InlineAsmRegClass::X86(X86InlineAsmRegClass::ymm_reg) + | InlineAsmRegClass::X86(X86InlineAsmRegClass::zmm_reg) => cx.type_f32(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::x87_reg) => unimplemented!(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => cx.type_i16(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg0) => cx.type_i16(), + InlineAsmRegClass::X86(X86InlineAsmRegClass::tmm_reg) => unimplemented!(), + InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => cx.type_i32(), + InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => { + bug!("LLVM backend does not support SPIR-V") + }, + InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg) => cx.type_i32(), + InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => cx.type_f64(), + InlineAsmRegClass::Err => unreachable!(), + } +} + +impl<'gcc, 'tcx> AsmMethods<'tcx> for CodegenCx<'gcc, 'tcx> { + fn codegen_global_asm(&self, template: &[InlineAsmTemplatePiece], operands: &[GlobalAsmOperandRef<'tcx>], options: InlineAsmOptions, _line_spans: &[Span]) { + let asm_arch = self.tcx.sess.asm_arch.unwrap(); + + // Default to Intel syntax on x86 + let att_dialect = matches!(asm_arch, InlineAsmArch::X86 | InlineAsmArch::X86_64) + && options.contains(InlineAsmOptions::ATT_SYNTAX); + + // Build the template string + let mut template_str = ".pushsection .text\n".to_owned(); + if att_dialect { + template_str.push_str(".att_syntax\n"); + } + for piece in template { + match *piece { + InlineAsmTemplatePiece::String(ref string) => { + let mut index = 0; + while index < string.len() { + // NOTE: gcc does not allow inline comment, so remove them. + let comment_index = string[index..].find("//") + .map(|comment_index| comment_index + index) + .unwrap_or(string.len()); + template_str.push_str(&string[index..comment_index]); + index = string[comment_index..].find('\n') + .map(|index| index + comment_index) + .unwrap_or(string.len()); + } + }, + InlineAsmTemplatePiece::Placeholder { operand_idx, modifier: _, span: _ } => { + match operands[operand_idx] { + GlobalAsmOperandRef::Const { ref string } => { + // Const operands get injected directly into the + // template. Note that we don't need to escape % + // here unlike normal inline assembly. + template_str.push_str(string); + } + + GlobalAsmOperandRef::SymFn { instance } => { + let function = get_fn(self, instance); + self.add_used_function(function); + // TODO(@Amanieu): Additional mangling is needed on + // some targets to add a leading underscore (Mach-O) + // or byte count suffixes (x86 Windows). + let name = self.tcx.symbol_name(instance).name; + template_str.push_str(name); + } + + GlobalAsmOperandRef::SymStatic { def_id } => { + // TODO(antoyo): set the global variable as used. + // TODO(@Amanieu): Additional mangling is needed on + // some targets to add a leading underscore (Mach-O). + let instance = Instance::mono(self.tcx, def_id); + let name = self.tcx.symbol_name(instance).name; + template_str.push_str(name); + } + } + } + } + } + + if att_dialect { + template_str.push_str("\n\t.intel_syntax noprefix"); + } + // NOTE: seems like gcc will put the asm in the wrong section, so set it to .text manually. + template_str.push_str("\n.popsection"); + self.context.add_top_level_asm(None, &template_str); + } +} + +fn modifier_to_gcc(arch: InlineAsmArch, reg: InlineAsmRegClass, modifier: Option<char>) -> Option<char> { + // The modifiers can be retrieved from + // https://gcc.gnu.org/onlinedocs/gcc/Modifiers.html#Modifiers + match reg { + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => modifier, + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg) + | InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => { + if modifier == Some('v') { None } else { modifier } + } + InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg) => None, + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg_low16) => None, + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low16) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::dreg_low8) => Some('P'), + InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8) + | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) => { + if modifier.is_none() { + Some('q') + } else { + modifier + } + } + InlineAsmRegClass::Hexagon(_) => None, + InlineAsmRegClass::LoongArch(_) => None, + InlineAsmRegClass::Mips(_) => None, + InlineAsmRegClass::Nvptx(_) => None, + InlineAsmRegClass::PowerPC(_) => None, + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg) + | InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => None, + InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::X86(X86InlineAsmRegClass::reg) + | InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => match modifier { + None => if arch == InlineAsmArch::X86_64 { Some('q') } else { Some('k') }, + Some('l') => Some('b'), + Some('h') => Some('h'), + Some('x') => Some('w'), + Some('e') => Some('k'), + Some('r') => Some('q'), + _ => unreachable!(), + }, + InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => None, + InlineAsmRegClass::X86(reg @ X86InlineAsmRegClass::xmm_reg) + | InlineAsmRegClass::X86(reg @ X86InlineAsmRegClass::ymm_reg) + | InlineAsmRegClass::X86(reg @ X86InlineAsmRegClass::zmm_reg) => match (reg, modifier) { + (X86InlineAsmRegClass::xmm_reg, None) => Some('x'), + (X86InlineAsmRegClass::ymm_reg, None) => Some('t'), + (X86InlineAsmRegClass::zmm_reg, None) => Some('g'), + (_, Some('x')) => Some('x'), + (_, Some('y')) => Some('t'), + (_, Some('z')) => Some('g'), + _ => unreachable!(), + }, + InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => None, + InlineAsmRegClass::X86( + X86InlineAsmRegClass::x87_reg + | X86InlineAsmRegClass::mmx_reg + | X86InlineAsmRegClass::kreg0 + | X86InlineAsmRegClass::tmm_reg, + ) => { + unreachable!("clobber-only") + } + InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => None, + InlineAsmRegClass::Bpf(_) => None, + InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_pair) + | InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_iw) + | InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => match modifier { + Some('h') => Some('B'), + Some('l') => Some('A'), + _ => None, + }, + InlineAsmRegClass::Avr(_) => None, + InlineAsmRegClass::S390x(_) => None, + InlineAsmRegClass::Msp430(_) => None, + InlineAsmRegClass::M68k(_) => None, + InlineAsmRegClass::CSKY(_) => None, + InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => { + bug!("LLVM backend does not support SPIR-V") + } + InlineAsmRegClass::Err => unreachable!(), + } +} |