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stage2 AArch64: bump up alignment of stack items fitting in regs

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This enables us to use more efficient loading and storing for these
small stack items
This commit is contained in:
joachimschmidt557
2023-01-03 19:20:55 +08:00
committed by Jakub Konka
parent 8032ecb730
commit 09122650ba
3 changed files with 18 additions and 14 deletions
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27
src/arch/aarch64/CodeGen.zig
View File

@@ -433,7 +433,7 @@ pub fn generate(
.prev_di_pc = 0,
.prev_di_line = module_fn.lbrace_line,
.prev_di_column = module_fn.lbrace_column,
.stack_size = mem.alignForwardGeneric(u32, function.max_end_stack, function.stack_align),
.stack_size = function.max_end_stack,
.saved_regs_stack_space = function.saved_regs_stack_space,
};
defer emit.deinit();
@@ -560,6 +560,7 @@ fn gen(self: *Self) !void {
const total_stack_size = self.max_end_stack + self.saved_regs_stack_space;
const aligned_total_stack_end = mem.alignForwardGeneric(u32, total_stack_size, self.stack_align);
const stack_size = aligned_total_stack_end - self.saved_regs_stack_space;
self.max_end_stack = stack_size;
if (math.cast(u12, stack_size)) |size| {
self.mir_instructions.set(backpatch_reloc, .{
.tag = .sub_immediate,
@@ -982,11 +983,16 @@ fn allocMem(
assert(abi_size > 0);
assert(abi_align > 0);
if (abi_align > self.stack_align)
self.stack_align = abi_align;
// In order to efficiently load and store stack items that fit
// into registers, we bump up the alignment to the next power of
// two.
const adjusted_align = if (abi_size > 8)
abi_align
else
std.math.ceilPowerOfTwoAssert(u32, abi_size);
// TODO find a free slot instead of always appending
const offset = mem.alignForwardGeneric(u32, self.next_stack_offset, abi_align) + abi_size;
const offset = mem.alignForwardGeneric(u32, self.next_stack_offset, adjusted_align) + abi_size;
self.next_stack_offset = offset;
self.max_end_stack = @max(self.max_end_stack, self.next_stack_offset);
@@ -5396,7 +5402,7 @@ fn setRegOrMem(self: *Self, ty: Type, loc: MCValue, val: MCValue) !void {
}
fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerError!void {
const abi_size = ty.abiSize(self.target.*);
const abi_size = @intCast(u32, ty.abiSize(self.target.*));
switch (mcv) {
.dead => unreachable,
.unreach, .none => return, // Nothing to do.
@@ -5404,7 +5410,7 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
if (!self.wantSafety())
return; // The already existing value will do just fine.
// TODO Upgrade this to a memset call when we have that available.
switch (ty.abiSize(self.target.*)) {
switch (abi_size) {
1 => return self.genSetStack(ty, stack_offset, .{ .immediate = 0xaa }),
2 => return self.genSetStack(ty, stack_offset, .{ .immediate = 0xaaaa }),
4 => return self.genSetStack(ty, stack_offset, .{ .immediate = 0xaaaaaaaa }),
@@ -5426,6 +5432,8 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
.register => |reg| {
switch (abi_size) {
1, 2, 4, 8 => {
assert(std.mem.isAlignedGeneric(u32, stack_offset, abi_size));
const tag: Mir.Inst.Tag = switch (abi_size) {
1 => .strb_stack,
2 => .strh_stack,
@@ -5438,7 +5446,7 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
.tag = tag,
.data = .{ .load_store_stack = .{
.rt = rt,
.offset = @intCast(u32, stack_offset),
.offset = stack_offset,
} },
});
},
@@ -6001,9 +6009,10 @@ fn airSelect(self: *Self, inst: Air.Inst.Index) !void {
}
fn airShuffle(self: *Self, inst: Air.Inst.Index) !void {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.Shuffle, ty_pl.payload).data;
const result: MCValue = if (self.liveness.isUnused(inst)) .dead else return self.fail("TODO implement airShuffle for {}", .{self.target.cpu.arch});
return self.finishAir(inst, result, .{ ty_op.operand, .none, .none });
return self.finishAir(inst, result, .{ extra.a, extra.b, .none });
}
fn airReduce(self: *Self, inst: Air.Inst.Index) !void {

2
test/behavior/basic.zig
View File

@@ -890,7 +890,6 @@ test "labeled block with runtime branch forwards its result location type to bre
}
test "try in labeled block doesn't cast to wrong type" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
const S = struct {
@@ -1036,7 +1035,6 @@ comptime {
}
test "switch inside @as gets correct type" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
var a: u32 = 0;

3
test/behavior/error.zig
View File

@@ -76,7 +76,6 @@ fn unwrapSimpleValueFromErrorDo() anyerror!isize {
}
test "error return in assignment" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
doErrReturnInAssignment() catch unreachable;
@@ -829,7 +828,6 @@ test "alignment of wrapping an error union payload" {
}
test "compare error union and error set" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
var a: anyerror = error.Foo;
@@ -889,7 +887,6 @@ test "field access of anyerror results in smaller error set" {
test "optional error union return type" {
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const S = struct {
fn foo() ?anyerror!u32 {