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Merge pull request #10034 from Snektron/stage2-slice

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stage2: slice and optional improvements
This commit is contained in:
Andrew Kelley
2021-10-25 19:41:19 -04:00
committed by GitHub
parent 30d01c8fea 21bf3b8066
commit df198ea60e
7 changed files with 127 additions and 77 deletions
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54
src/Sema.zig
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@@ -8013,14 +8013,24 @@ fn analyzePtrArithmetic(
const offset = try sema.coerce(block, Type.usize, uncasted_offset, offset_src);
// TODO adjust the return type according to alignment and other factors
const runtime_src = rs: {
if (try sema.resolveDefinedValue(block, ptr_src, ptr)) |ptr_val| {
if (try sema.resolveDefinedValue(block, offset_src, offset)) |offset_val| {
if (try sema.resolveMaybeUndefVal(block, ptr_src, ptr)) |ptr_val| {
if (try sema.resolveMaybeUndefVal(block, offset_src, offset)) |offset_val| {
const ptr_ty = sema.typeOf(ptr);
const offset_int = offset_val.toUnsignedInt();
const new_ptr_ty = ptr_ty; // TODO modify alignment
if (ptr_val.isUndef() or offset_val.isUndef()) {
return sema.addConstUndef(new_ptr_ty);
}
const offset_int = offset_val.toUnsignedInt();
if (ptr_val.getUnsignedInt()) |addr| {
const target = sema.mod.getTarget();
const elem_ty = ptr_ty.childType();
const ptr_child_ty = ptr_ty.childType();
const elem_ty = if (ptr_ty.isSinglePointer() and ptr_child_ty.zigTypeTag() == .Array)
ptr_child_ty.childType()
else
ptr_child_ty;
const elem_size = elem_ty.abiSize(target);
const new_addr = switch (air_tag) {
.ptr_add => addr + elem_size * offset_int,
@@ -13217,8 +13227,8 @@ fn analyzeSlice(
var elem_ty = ptr_ptr_child_ty.childType();
switch (ptr_ptr_child_ty.zigTypeTag()) {
.Array => {},
.Pointer => {
if (ptr_ptr_child_ty.isSinglePointer()) {
.Pointer => switch (ptr_ptr_child_ty.ptrSize()) {
.One => {
const double_child_ty = ptr_ptr_child_ty.childType();
if (double_child_ty.zigTypeTag() == .Array) {
ptr_or_slice = try sema.analyzeLoad(block, src, ptr_ptr, ptr_src);
@@ -13228,10 +13238,23 @@ fn analyzeSlice(
} else {
return sema.fail(block, ptr_src, "slice of single-item pointer", .{});
}
}
},
.Many, .C => {
ptr_or_slice = try sema.analyzeLoad(block, src, ptr_ptr, ptr_src);
slice_ty = ptr_ptr_child_ty;
array_ty = ptr_ptr_child_ty;
elem_ty = ptr_ptr_child_ty.childType();
},
.Slice => {
ptr_or_slice = try sema.analyzeLoad(block, src, ptr_ptr, ptr_src);
slice_ty = ptr_ptr_child_ty;
array_ty = ptr_ptr_child_ty;
elem_ty = ptr_ptr_child_ty.childType();
},
},
else => return sema.fail(block, ptr_src, "slice of non-array type '{}'", .{ptr_ptr_child_ty}),
}
const ptr = if (slice_ty.isSlice())
try sema.analyzeSlicePtr(block, src, ptr_or_slice, slice_ty, ptr_src)
else
@@ -13263,7 +13286,6 @@ fn analyzeSlice(
const new_len = try sema.analyzeArithmetic(block, .sub, end, start, src, end_src, start_src);
const opt_new_ptr_val = try sema.resolveDefinedValue(block, ptr_src, new_ptr);
const opt_new_len_val = try sema.resolveDefinedValue(block, src, new_len);
const new_ptr_ty_info = sema.typeOf(new_ptr).ptrInfo().data;
@@ -13287,11 +13309,21 @@ fn analyzeSlice(
.size = .One,
});
if (opt_new_ptr_val) |new_ptr_val| {
return sema.addConstant(return_ty, new_ptr_val);
} else {
const opt_new_ptr_val = try sema.resolveMaybeUndefVal(block, ptr_src, new_ptr);
const new_ptr_val = opt_new_ptr_val orelse {
return block.addBitCast(return_ty, new_ptr);
};
if (!new_ptr_val.isUndef()) {
return sema.addConstant(return_ty, new_ptr_val);
}
// Special case: @as([]i32, undefined)[x..x]
if (new_len_int == 0) {
return sema.addConstUndef(return_ty);
}
return sema.fail(block, ptr_src, "non-zero length slice of undefined pointer", .{});
}
const return_ty = try Type.ptr(sema.arena, .{