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stack alinment in sysv calls

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veclav talica 2023-09-20 10:54:24 +05:00
parent b66c3dca14
commit 8de4140b00
2 changed files with 21 additions and 13 deletions
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18
src/arch/x86-64/ve-sistema.zig
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@ -75,18 +75,15 @@ pub fn generateOpZovSysvFromPrototype(prototype: anytype) !*const fn () callconv
var source_buffer = [_]u8{0} ** AsmBufferLimit;
var source_needle: usize = 0;
// todo: Align callee frame to 16?
// > shrq $4, %%rsp
// > addq $1, %%rsp
// > shlq $4, %%rsp
// idea: Try using REP for big consequent memory pushes.
// todo: In-stack returns by pointing %rdi directly to final destination.
// todo: Test whether aligning by shifting is better.
const Prelude =
\\ movq %%rsp, %%rbp # Move stack pointer in non-volatile %rbp to restore later
\\ subq $0x8, %%rsp
\\ andq $-16, %%rsp # Align stack so that %rsp + 8 in callee is 16 aligned.
\\ addq $0x{x}, %%rsp
\\
;
@ -102,9 +99,6 @@ pub fn generateOpZovSysvFromPrototype(prototype: anytype) !*const fn () callconv
\\
;
@memcpy(source_buffer[source_needle .. source_needle + Prelude.len], Prelude[0..]);
source_needle += Prelude.len;
var integer_allocation: usize = 0;
const IntegerAllocations = [_][]const u8{ "rdi", "rsi", "rdx", "rcx", "r8", "r9", "stack" };
// var sse_allocation: enum { xmm0, xmm1, xmm2, xmm3, xmm4, xmm5, xmm6, xmm7, stack } = .xmm0;
@ -118,6 +112,12 @@ pub fn generateOpZovSysvFromPrototype(prototype: anytype) !*const fn () callconv
parameter_stack_size += 8 * classes.len;
}
source_needle += (try std.fmt.bufPrint(
source_buffer[source_needle..],
Prelude[0..],
.{if (parameter_stack_size % 16 == 0) 16 else 8},
)).len;
// Push parameters to appropriate registers and stack positions.
var stack_offset: usize = parameter_stack_size;
for (func.params) |param| {

16
src/main.zig
View File

@ -1,12 +1,18 @@
const std = @import("std");
const tolmac = @import("tolmac.zig");
fn printInt(int: u64, other: u32, another: u16) callconv(.SysV) void {
fn printInt3(int: u64, other: u32, another: u16) callconv(.SysV) void {
@setAlignStack(16);
std.debug.print("test: {}, {}, {}\n", .{ int, other, another });
}
const opPrintIntZov = tolmac.generateOpZovSysvFromPrototype(printInt) catch unreachable;
fn printInt2(int: u64, other: u8) callconv(.SysV) void {
@setAlignStack(16);
std.debug.print("test: {}, {}\n", .{ int, other });
}
const opPrintInt3Zov = tolmac.generateOpZovSysvFromPrototype(printInt3) catch unreachable;
const opPrintInt2Zov = tolmac.generateOpZovSysvFromPrototype(printInt2) catch unreachable;
pub fn main() !void {
// todo: Mixing return addresses in stack poses a challenge, hm.
@ -27,9 +33,11 @@ pub fn main() !void {
10,
@as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
20,
@as(tolmac.Word, @intFromPtr(opPrintIntZov)),
@as(tolmac.Word, @intFromPtr(&printInt)),
@as(tolmac.Word, @intFromPtr(opPrintInt3Zov)),
@as(tolmac.Word, @intFromPtr(&printInt3)),
@as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
@as(tolmac.Word, @intFromPtr(opPrintInt2Zov)),
@as(tolmac.Word, @intFromPtr(&printInt2)),
@as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
@as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
@as(tolmac.Word, @intFromPtr(&tolmac.opReturn)),