diff options
Diffstat (limited to 'src/codegen')
| -rw-r--r-- | src/codegen/llvm.zig | 57 |
1 files changed, 35 insertions, 22 deletions
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig index 148d83bdef..85ac706d7c 100644 --- a/src/codegen/llvm.zig +++ b/src/codegen/llvm.zig @@ -6179,7 +6179,6 @@ pub const FuncGen = struct { const elem_alignment = elem_ty.abiAlignment(mod).toLlvm(); return self.loadByRef(elem_ptr, elem_ty, elem_alignment, .normal); } else { - const elem_llvm_ty = try o.lowerType(elem_ty); if (Air.refToIndex(bin_op.lhs)) |lhs_index| { if (self.air.instructions.items(.tag)[lhs_index] == .load) { const load_data = self.air.instructions.items(.data)[lhs_index]; @@ -6201,7 +6200,7 @@ pub const FuncGen = struct { &indices, "", ); - return self.wip.load(.normal, elem_llvm_ty, gep, .default, ""); + return self.loadTruncate(.normal, elem_ty, gep, .default); }, else => {}, } @@ -6210,7 +6209,7 @@ pub const FuncGen = struct { } const elem_ptr = try self.wip.gep(.inbounds, array_llvm_ty, array_llvm_val, &indices, ""); - return self.wip.load(.normal, elem_llvm_ty, elem_ptr, .default, ""); + return self.loadTruncate(.normal, elem_ty, elem_ptr, .default); } } @@ -6378,13 +6377,12 @@ pub const FuncGen = struct { const payload_index = @intFromBool(layout.tag_align.compare(.gte, layout.payload_align)); const field_ptr = try self.wip.gepStruct(union_llvm_ty, struct_llvm_val, payload_index, ""); - const llvm_field_ty = try o.lowerType(field_ty); const payload_alignment = layout.payload_align.toLlvm(); if (isByRef(field_ty, mod)) { if (canElideLoad(self, body_tail)) return field_ptr; return self.loadByRef(field_ptr, field_ty, payload_alignment, .normal); } else { - return self.wip.load(.normal, llvm_field_ty, field_ptr, payload_alignment, ""); + return self.loadTruncate(.normal, field_ty, field_ptr, payload_alignment); } }, else => unreachable, @@ -10219,8 +10217,7 @@ pub const FuncGen = struct { return fg.loadByRef(payload_ptr, payload_ty, payload_alignment, .normal); } - const payload_llvm_ty = try o.lowerType(payload_ty); - return fg.wip.load(.normal, payload_llvm_ty, payload_ptr, payload_alignment, ""); + return fg.loadTruncate(.normal, payload_ty, payload_ptr, payload_alignment); } assert(!isByRef(payload_ty, mod)); @@ -10321,6 +10318,36 @@ pub const FuncGen = struct { } } + /// Load a value and, if needed, mask out padding bits for non byte-sized integer values. + fn loadTruncate( + fg: *FuncGen, + access_kind: Builder.MemoryAccessKind, + payload_ty: Type, + payload_ptr: Builder.Value, + payload_alignment: Builder.Alignment, + ) !Builder.Value { + // from https://llvm.org/docs/LangRef.html#load-instruction : + // "When loading a value of a type like i20 with a size that is not an integral number of bytes, the result is undefined if the value was not originally written using a store of the same type. " + // => so load the byte aligned value and trunc the unwanted bits. + + const o = fg.dg.object; + const mod = o.module; + const payload_llvm_ty = try o.lowerType(payload_ty); + const load_llvm_ty = if (payload_ty.isAbiInt(mod)) + try o.builder.intType(@intCast(payload_ty.abiSize(mod) * 8)) + else + payload_llvm_ty; + const loaded = try fg.wip.load(access_kind, load_llvm_ty, payload_ptr, payload_alignment, ""); + const shifted = if (payload_llvm_ty != load_llvm_ty and o.target.cpu.arch.endian() == .Big) + try fg.wip.bin(.lshr, loaded, try o.builder.intValue( + load_llvm_ty, + (payload_ty.abiSize(mod) - (std.math.divCeil(u64, payload_ty.bitSize(mod), 8) catch unreachable)) * 8, + ), "") + else + loaded; + return fg.wip.conv(.unneeded, shifted, payload_llvm_ty, ""); + } + /// Load a by-ref type by constructing a new alloca and performing a memcpy. fn loadByRef( fg: *FuncGen, @@ -10378,21 +10405,7 @@ pub const FuncGen = struct { if (isByRef(elem_ty, mod)) { return self.loadByRef(ptr, elem_ty, ptr_alignment, access_kind); } - const llvm_elem_ty = try o.lowerType(elem_ty); - const llvm_load_ty = if (elem_ty.isAbiInt(mod)) - try o.builder.intType(@intCast(elem_ty.abiSize(mod) * 8)) - else - llvm_elem_ty; - const loaded = try self.wip.load(access_kind, llvm_load_ty, ptr, ptr_alignment, ""); - const shifted = if (llvm_elem_ty != llvm_load_ty and o.target.cpu.arch.endian() == .Big) - try self.wip.bin(.lshr, loaded, try o.builder.intValue( - llvm_load_ty, - (elem_ty.abiSize(mod) - (std.math.divCeil(u64, elem_ty.bitSize(mod), 8) catch - unreachable)) * 8, - ), "") - else - loaded; - return self.wip.conv(.unneeded, shifted, llvm_elem_ty, ""); + return self.loadTruncate(access_kind, elem_ty, ptr, ptr_alignment); } const containing_int_ty = try o.builder.intType(@intCast(info.packed_offset.host_size * 8)); |