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Implement asm goto for LLVM and GCC backend

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This commit is contained in:
Gary Guo 2023-12-27 04:08:04 +00:00
parent 27e6ee102e
commit 5e4fd6bc23
5 changed files with 84 additions and 22 deletions
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31
compiler/rustc_codegen_gcc/src/asm.rs
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@ -107,7 +107,7 @@ enum ConstraintOrRegister {
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>)>) {
fn codegen_inline_asm(&mut self, template: &[InlineAsmTemplatePiece], rust_operands: &[InlineAsmOperandRef<'tcx, Self>], options: InlineAsmOptions, span: &[Span], instance: Instance<'_>, dest: Option<Self::BasicBlock>, _catch_funclet: Option<(Self::BasicBlock, Option<&Self::Funclet>)>) {
if options.contains(InlineAsmOptions::MAY_UNWIND) {
self.sess().dcx()
.create_err(UnwindingInlineAsm { span: span[0] })
@ -126,6 +126,10 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
// added to `outputs.len()`
let mut inputs = vec![];
// GCC index of a label equals its position in the array added to
// `outputs.len() + inputs.len()`.
let mut labels = vec![];
// Clobbers collected from `out("explicit register") _` and `inout("expl_reg") var => _`
let mut clobbers = vec![];
@ -269,6 +273,10 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
// some targets to add a leading underscore (Mach-O).
constants_len += self.tcx.symbol_name(Instance::mono(self.tcx, def_id)).name.len();
}
InlineAsmOperandRef::Label { label } => {
labels.push(label);
}
}
}
@ -368,6 +376,10 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
InlineAsmOperandRef::Const { .. } => {
// processed in the previous pass
}
InlineAsmOperandRef::Label { .. } => {
// processed in the previous pass
}
}
}
@ -454,6 +466,14 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
InlineAsmOperandRef::Const { ref string } => {
template_str.push_str(string);
}
InlineAsmOperandRef::Label { label } => {
let label_gcc_index = labels.iter()
.position(|&l| l == label)
.expect("wrong rust index");
let gcc_index = label_gcc_index + outputs.len() + inputs.len();
push_to_template(Some('l'), gcc_index);
}
}
}
}
@ -466,7 +486,12 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
// 4. Generate Extended Asm block
let block = self.llbb();
let extended_asm = block.add_extended_asm(None, &template_str);
let extended_asm = if let Some(dest) = dest {
assert!(!labels.is_empty());
block.end_with_extended_asm_goto(None, &template_str, &labels, Some(dest))
} else {
block.add_extended_asm(None, &template_str)
};
for op in &outputs {
extended_asm.add_output_operand(None, &op.to_constraint(), op.tmp_var);
@ -494,7 +519,7 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
if !options.contains(InlineAsmOptions::NOSTACK) {
// TODO(@Commeownist): figure out how to align stack
}
if options.contains(InlineAsmOptions::NORETURN) {
if dest.is_none() && 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);