diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/va_arg.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/va_arg.rs | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/va_arg.rs b/compiler/rustc_codegen_llvm/src/va_arg.rs index ceb3d5a84..b19398e68 100644 --- a/compiler/rustc_codegen_llvm/src/va_arg.rs +++ b/compiler/rustc_codegen_llvm/src/va_arg.rs @@ -175,6 +175,89 @@ fn emit_aapcs_va_arg<'ll, 'tcx>( val } +fn emit_s390x_va_arg<'ll, 'tcx>( + bx: &mut Builder<'_, 'll, 'tcx>, + list: OperandRef<'tcx, &'ll Value>, + target_ty: Ty<'tcx>, +) -> &'ll Value { + // Implementation of the s390x ELF ABI calling convention for va_args see + // https://github.com/IBM/s390x-abi (chapter 1.2.4) + let va_list_addr = list.immediate(); + let va_list_layout = list.deref(bx.cx).layout; + let va_list_ty = va_list_layout.llvm_type(bx); + let layout = bx.cx.layout_of(target_ty); + + let in_reg = bx.append_sibling_block("va_arg.in_reg"); + let in_mem = bx.append_sibling_block("va_arg.in_mem"); + let end = bx.append_sibling_block("va_arg.end"); + + // FIXME: vector ABI not yet supported. + let target_ty_size = bx.cx.size_of(target_ty).bytes(); + let indirect: bool = target_ty_size > 8 || !target_ty_size.is_power_of_two(); + let unpadded_size = if indirect { 8 } else { target_ty_size }; + let padded_size = 8; + let padding = padded_size - unpadded_size; + + let gpr_type = indirect || !layout.is_single_fp_element(bx.cx); + let (max_regs, reg_count_field, reg_save_index, reg_padding) = + if gpr_type { (5, 0, 2, padding) } else { (4, 1, 16, 0) }; + + // Check whether the value was passed in a register or in memory. + let reg_count = bx.struct_gep( + va_list_ty, + va_list_addr, + va_list_layout.llvm_field_index(bx.cx, reg_count_field), + ); + let reg_count_v = bx.load(bx.type_i64(), reg_count, Align::from_bytes(8).unwrap()); + let use_regs = bx.icmp(IntPredicate::IntULT, reg_count_v, bx.const_u64(max_regs)); + bx.cond_br(use_regs, in_reg, in_mem); + + // Emit code to load the value if it was passed in a register. + bx.switch_to_block(in_reg); + + // Work out the address of the value in the register save area. + let reg_ptr = + bx.struct_gep(va_list_ty, va_list_addr, va_list_layout.llvm_field_index(bx.cx, 3)); + let reg_ptr_v = bx.load(bx.type_i8p(), reg_ptr, bx.tcx().data_layout.pointer_align.abi); + let scaled_reg_count = bx.mul(reg_count_v, bx.const_u64(8)); + let reg_off = bx.add(scaled_reg_count, bx.const_u64(reg_save_index * 8 + reg_padding)); + let reg_addr = bx.gep(bx.type_i8(), reg_ptr_v, &[reg_off]); + + // Update the register count. + let new_reg_count_v = bx.add(reg_count_v, bx.const_u64(1)); + bx.store(new_reg_count_v, reg_count, Align::from_bytes(8).unwrap()); + bx.br(end); + + // Emit code to load the value if it was passed in memory. + bx.switch_to_block(in_mem); + + // Work out the address of the value in the argument overflow area. + let arg_ptr = + bx.struct_gep(va_list_ty, va_list_addr, va_list_layout.llvm_field_index(bx.cx, 2)); + let arg_ptr_v = bx.load(bx.type_i8p(), arg_ptr, bx.tcx().data_layout.pointer_align.abi); + let arg_off = bx.const_u64(padding); + let mem_addr = bx.gep(bx.type_i8(), arg_ptr_v, &[arg_off]); + + // Update the argument overflow area pointer. + let arg_size = bx.cx().const_u64(padded_size); + let new_arg_ptr_v = bx.inbounds_gep(bx.type_i8(), arg_ptr_v, &[arg_size]); + bx.store(new_arg_ptr_v, arg_ptr, bx.tcx().data_layout.pointer_align.abi); + bx.br(end); + + // Return the appropriate result. + bx.switch_to_block(end); + let val_addr = bx.phi(bx.type_i8p(), &[reg_addr, mem_addr], &[in_reg, in_mem]); + let val_type = layout.llvm_type(bx); + let val_addr = if indirect { + let ptr_type = bx.cx.type_ptr_to(val_type); + let ptr_addr = bx.bitcast(val_addr, bx.cx.type_ptr_to(ptr_type)); + bx.load(ptr_type, ptr_addr, bx.tcx().data_layout.pointer_align.abi) + } else { + bx.bitcast(val_addr, bx.cx.type_ptr_to(val_type)) + }; + bx.load(val_type, val_addr, layout.align.abi) +} + pub(super) fn emit_va_arg<'ll, 'tcx>( bx: &mut Builder<'_, 'll, 'tcx>, addr: OperandRef<'tcx, &'ll Value>, @@ -200,6 +283,7 @@ pub(super) fn emit_va_arg<'ll, 'tcx>( emit_ptr_va_arg(bx, addr, target_ty, false, Align::from_bytes(8).unwrap(), true) } "aarch64" => emit_aapcs_va_arg(bx, addr, target_ty), + "s390x" => emit_s390x_va_arg(bx, addr, target_ty), // Windows x86_64 "x86_64" if target.is_like_windows => { let target_ty_size = bx.cx.size_of(target_ty).bytes(); |