diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/va_arg.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/va_arg.rs | 94 |
1 files changed, 62 insertions, 32 deletions
diff --git a/compiler/rustc_codegen_llvm/src/va_arg.rs b/compiler/rustc_codegen_llvm/src/va_arg.rs index 172c66a7af1..2d6cd51aead 100644 --- a/compiler/rustc_codegen_llvm/src/va_arg.rs +++ b/compiler/rustc_codegen_llvm/src/va_arg.rs @@ -89,11 +89,35 @@ fn emit_aapcs_va_arg<'ll, 'tcx>( list: OperandRef<'tcx, &'ll Value>, target_ty: Ty<'tcx>, ) -> &'ll Value { + let dl = bx.cx.data_layout(); + // Implementation of the AAPCS64 calling convention for va_args see // https://github.com/ARM-software/abi-aa/blob/master/aapcs64/aapcs64.rst + // + // typedef struct va_list { + // void * stack; // next stack param + // void * gr_top; // end of GP arg reg save area + // void * vr_top; // end of FP/SIMD arg reg save area + // int gr_offs; // offset from gr_top to next GP register arg + // int vr_offs; // offset from vr_top to next FP/SIMD register arg + // } va_list; 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); + + // There is no padding between fields since `void*` is size=8 align=8, `int` is size=4 align=4. + // See https://github.com/ARM-software/abi-aa/blob/master/aapcs64/aapcs64.rst + // Table 1, Byte size and byte alignment of fundamental data types + // Table 3, Mapping of C & C++ built-in data types + let ptr_offset = 8; + let i32_offset = 4; + let gr_top = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(ptr_offset)]); + let vr_top = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(2 * ptr_offset)]); + let gr_offs = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(3 * ptr_offset)]); + let vr_offs = bx.inbounds_gep( + bx.type_i8(), + va_list_addr, + &[bx.cx.const_usize(3 * ptr_offset + i32_offset)], + ); + let layout = bx.cx.layout_of(target_ty); let maybe_reg = bx.append_sibling_block("va_arg.maybe_reg"); @@ -104,16 +128,12 @@ fn emit_aapcs_va_arg<'ll, 'tcx>( let offset_align = Align::from_bytes(4).unwrap(); let gr_type = target_ty.is_any_ptr() || target_ty.is_integral(); - let (reg_off, reg_top_index, slot_size) = if gr_type { - let gr_offs = - bx.struct_gep(va_list_ty, va_list_addr, va_list_layout.llvm_field_index(bx.cx, 3)); + let (reg_off, reg_top, slot_size) = if gr_type { let nreg = (layout.size.bytes() + 7) / 8; - (gr_offs, va_list_layout.llvm_field_index(bx.cx, 1), nreg * 8) + (gr_offs, gr_top, nreg * 8) } else { - let vr_off = - bx.struct_gep(va_list_ty, va_list_addr, va_list_layout.llvm_field_index(bx.cx, 4)); let nreg = (layout.size.bytes() + 15) / 16; - (vr_off, va_list_layout.llvm_field_index(bx.cx, 2), nreg * 16) + (vr_offs, vr_top, nreg * 16) }; // if the offset >= 0 then the value will be on the stack @@ -141,8 +161,7 @@ fn emit_aapcs_va_arg<'ll, 'tcx>( bx.switch_to_block(in_reg); let top_type = bx.type_ptr(); - let top = bx.struct_gep(va_list_ty, va_list_addr, reg_top_index); - let top = bx.load(top_type, top, bx.tcx().data_layout.pointer_align.abi); + let top = bx.load(top_type, reg_top, dl.pointer_align.abi); // reg_value = *(@top + reg_off_v); let mut reg_addr = bx.gep(bx.type_i8(), top, &[reg_off_v]); @@ -173,11 +192,33 @@ fn emit_s390x_va_arg<'ll, 'tcx>( list: OperandRef<'tcx, &'ll Value>, target_ty: Ty<'tcx>, ) -> &'ll Value { + let dl = bx.cx.data_layout(); + // Implementation of the s390x ELF ABI calling convention for va_args see // https://github.com/IBM/s390x-abi (chapter 1.2.4) + // + // typedef struct __va_list_tag { + // long __gpr; + // long __fpr; + // void *__overflow_arg_area; + // void *__reg_save_area; + // } va_list[1]; 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); + + // There is no padding between fields since `long` and `void*` both have size=8 align=8. + // https://github.com/IBM/s390x-abi (Table 1.1.: Scalar types) + let i64_offset = 8; + let ptr_offset = 8; + let gpr = va_list_addr; + let fpr = bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(i64_offset)]); + let overflow_arg_area = + bx.inbounds_gep(bx.type_i8(), va_list_addr, &[bx.cx.const_usize(2 * i64_offset)]); + let reg_save_area = bx.inbounds_gep( + bx.type_i8(), + va_list_addr, + &[bx.cx.const_usize(2 * i64_offset + ptr_offset)], + ); + let layout = bx.cx.layout_of(target_ty); let in_reg = bx.append_sibling_block("va_arg.in_reg"); @@ -192,15 +233,10 @@ fn emit_s390x_va_arg<'ll, 'tcx>( 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) }; + let (max_regs, reg_count, reg_save_index, reg_padding) = + if gpr_type { (5, gpr, 2, padding) } else { (4, fpr, 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); @@ -209,9 +245,7 @@ fn emit_s390x_va_arg<'ll, 'tcx>( 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_ptr(), reg_ptr, bx.tcx().data_layout.pointer_align.abi); + let reg_ptr_v = bx.load(bx.type_ptr(), reg_save_area, dl.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]); @@ -225,27 +259,23 @@ fn emit_s390x_va_arg<'ll, 'tcx>( 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_ptr(), arg_ptr, bx.tcx().data_layout.pointer_align.abi); + let arg_ptr_v = + bx.load(bx.type_ptr(), overflow_arg_area, 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.store(new_arg_ptr_v, overflow_arg_area, dl.pointer_align.abi); bx.br(end); // Return the appropriate result. bx.switch_to_block(end); let val_addr = bx.phi(bx.type_ptr(), &[reg_addr, mem_addr], &[in_reg, in_mem]); let val_type = layout.llvm_type(bx); - let val_addr = if indirect { - bx.load(bx.cx.type_ptr(), val_addr, bx.tcx().data_layout.pointer_align.abi) - } else { - val_addr - }; + let val_addr = + if indirect { bx.load(bx.cx.type_ptr(), val_addr, dl.pointer_align.abi) } else { val_addr }; bx.load(val_type, val_addr, layout.align.abi) } |