authorgravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2022-07-20 18:22:25-04:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2022-07-20 18:22:25-04:00
logc1f3aca6027baaae781503af579767d208f8f172
treea29344d24999157b40a3644d25e941d482663913
parentde62bd06472e5603fd2afb6f50d688d54f4098b4
parent379beceffd1b0a0b0d8f3163dc02eba1e53ffa39
signaturebadge-question-mark Signed by PGP key 4AEE18F83AFDEB23

Merge pull request #12177 from Vexu/packed-ptr

stage2 llvm: fix handling of pointer fields in packed structs

2 files changed, 31 insertions(+), 1 deletions(-)

src/codegen/llvm.zig+9-1
...@@ -5149,6 +5149,11 @@ pub const FuncGen = struct {...@@ -5149,6 +5149,11 @@ pub const FuncGen = struct {
5149 const same_size_int = self.context.intType(elem_bits);5149 const same_size_int = self.context.intType(elem_bits);
5150 const truncated_int = self.builder.buildTrunc(shifted_value, same_size_int, "");5150 const truncated_int = self.builder.buildTrunc(shifted_value, same_size_int, "");
5151 return self.builder.buildBitCast(truncated_int, elem_llvm_ty, "");5151 return self.builder.buildBitCast(truncated_int, elem_llvm_ty, "");
5152 } else if (field_ty.zigTypeTag() == .Pointer) {
5153 const elem_bits = @intCast(c_uint, field_ty.bitSize(target));
5154 const same_size_int = self.context.intType(elem_bits);
5155 const truncated_int = self.builder.buildTrunc(shifted_value, same_size_int, "");
5156 return self.builder.buildIntToPtr(truncated_int, elem_llvm_ty, "");
5152 }5157 }
5153 return self.builder.buildTrunc(shifted_value, elem_llvm_ty, "");5158 return self.builder.buildTrunc(shifted_value, elem_llvm_ty, "");
5154 },5159 },
...@@ -7999,7 +8004,10 @@ pub const FuncGen = struct {...@@ -7999,7 +8004,10 @@ pub const FuncGen = struct {
7999 const non_int_val = try self.resolveInst(elem);8004 const non_int_val = try self.resolveInst(elem);
8000 const ty_bit_size = @intCast(u16, field.ty.bitSize(target));8005 const ty_bit_size = @intCast(u16, field.ty.bitSize(target));
8001 const small_int_ty = self.dg.context.intType(ty_bit_size);8006 const small_int_ty = self.dg.context.intType(ty_bit_size);
8002 const small_int_val = self.builder.buildBitCast(non_int_val, small_int_ty, "");8007 const small_int_val = if (field.ty.zigTypeTag() == .Pointer)
8008 self.builder.buildPtrToInt(non_int_val, small_int_ty, "")
8009 else
8010 self.builder.buildBitCast(non_int_val, small_int_ty, "");
8003 const shift_rhs = int_llvm_ty.constInt(running_bits, .False);8011 const shift_rhs = int_llvm_ty.constInt(running_bits, .False);
8004 // If the field is as large as the entire packed struct, this8012 // If the field is as large as the entire packed struct, this
8005 // zext would go from, e.g. i16 to i16. This is legal with8013 // zext would go from, e.g. i16 to i16. This is legal with
test/behavior/packed-struct.zig+22
...@@ -413,3 +413,25 @@ test "byte-aligned field pointer offsets" {...@@ -413,3 +413,25 @@ test "byte-aligned field pointer offsets" {
413 try S.doTheTest();413 try S.doTheTest();
414 comptime try S.doTheTest();414 comptime try S.doTheTest();
415}415}
416
417test "load pointer from packed struct" {
418 if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
419 if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
420 if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
421 if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
422 if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
423
424 const A = struct {
425 index: u16,
426 };
427 const B = packed struct {
428 x: *A,
429 y: u32,
430 };
431 var a: A = .{ .index = 123 };
432 var b_list: []B = &.{.{ .x = &a, .y = 99 }};
433 for (b_list) |b| {
434 var i = b.x.index;
435 try expect(i == 123);
436 }
437}