diff options
| -rw-r--r-- | lib/objc-asm.S | 113 | ||||
| -rw-r--r-- | test/test-imp-forwarding.m | 15 |
2 files changed, 89 insertions, 39 deletions
diff --git a/lib/objc-asm.S b/lib/objc-asm.S index d3dae8a..94d9de9 100644 --- a/lib/objc-asm.S +++ b/lib/objc-asm.S @@ -1,50 +1,72 @@ -/* These all try to re-invoke old_ptr. To make things worse, we don't know - * whether it will be called as stret or not, so we have to guess. */ +/* These all forward to the IMP obtained from block->get_imp(block); this + * signature is just so that I don't have to have two different assembly + * implementations for the temporary and fake-old blocks. To make things + * confusing, we don't know whether it will be called as stret or not, so we + * have to guess. + * (Could avoid the guessing by generating custom assembly instead, like + * Substrate does, but meh.) + */ .globl _temp_block_invoke .section __TEXT,__text,regular,pure_instructions #if defined(__x86_64__) _temp_block_invoke: push %rcx - mov 0x10(%rsi), %rax; /* block if stret, else self */ + mov 0x10(%rsi), %rax /* block if stret, else self */ lea _temp_block_invoke(%rip), %rcx cmp %rax, %rcx pop %rcx je 2f - mov %rdi, %rax - mov %rsi, %rdi - mov 0x28(%rax), %rsi - mov 0x20(%rax), %rax - jmp *(%rax) + + mov 0x20(%rdi), %rax /* get_imp */ + push %rdi; push %rsi; push %rdx; push %rcx; push %r8; push %r9 + call *%rax + pop %r9; pop %r8; pop %rcx; pop %rdx; pop %rdi; pop %rsi + mov 0x28(%rsi), %rsi /* selector */ + jmp *%rax 2: /* stret */ - mov %rsi, %rax - mov %rdx, %rsi - mov 0x28(%rsi), %rdx - mov 0x20(%rsi), %rax - jmp *(%rax) + mov 0x20(%rsi), %rax /* get_imp */ + push %rdi; push %rsi; push %rdx; push %rcx; push %r8; push %r9 + mov %rsi, %rdi + call *%rax + pop %r9; pop %r8; pop %rcx; pop %rsi; pop %rdx; pop %rdi + mov 0x28(%rdx), %rdx /* selector */ + jmp *%rax #elif defined(__i386__) _temp_block_invoke: call 1f 1: pop %edx lea _temp_block_invoke-1b(%edx), %edx - mov 8(%esp), %ecx; /* block if stret, else self */ + mov 8(%esp), %ecx /* block if stret, else self */ mov 0xc(%ecx), %eax cmp %eax, %edx je 2f - mov 4(%esp), %eax; /* block */ - mov %ecx, 4(%esp) - mov 0x18(%eax), %ecx + + mov 4(%esp), %eax /* block */ + push %eax + mov 0x14(%eax), %eax /* get_imp */ + call *%eax + add $4, %esp + mov 8(%esp), %edx /* self */ + mov 4(%esp), %ecx /* block */ + mov %edx, 4(%esp) + mov 0x18(%ecx), %ecx mov %ecx, 8(%esp) - mov 0x14(%eax), %eax - jmp *(%eax) + jmp *%eax 2: /* stret */ - mov 12(%esp), %ecx; /* self */ - mov 8(%esp), %eax; /* block */ - mov %ecx, 4(%esp) - mov 0x18(%eax), %ecx + int3 + mov 8(%esp), %eax /* block */ + push %eax + mov 0x14(%eax), %eax /* get_imp */ + call *%eax + add $4, %esp + int3 + mov 12(%esp), %ecx /* self */ + mov %ecx, 8(%esp) + mov 8(%esp), %ecx /* block */ + mov 0x18(%ecx), %ecx mov %ecx, 12(%esp) - mov 0x14(%eax), %eax - jmp *(%eax) + jmp *%eax #elif defined(__arm__) .thumb_func _temp_block_invoke .thumb @@ -54,28 +76,47 @@ _temp_block_invoke: adr r12, 1b cmp r9, r12 beq 2f + + push {r0-r4, lr} /* r4 for align */ + ldr r9, [r0, #0x14] + blx r9 + mov r12, r0 + pop {r0-r4, lr} mov r9, r0 mov r0, r1 ldr r1, [r9, #0x18] - ldr r9, [r9, #0x14] - ldr r9, [r9] - bx r9 + bx r12 2: /* stret */ + push {r0-r3, lr} + ldr r9, [r1, #0x14] + blx r9 + mov r12, r0 + pop {r0-r3, lr} mov r9, r1 mov r1, r2 ldr r2, [r9, #0x18] - ldr r9, [r9, #0x14] - ldr r9, [r9] - bx r9 + bx r12 #elif defined(__arm64__) .align 2 _temp_block_invoke: - mov x9, x0 - mov x0, x1 + stp x7, x6, [sp, #-0x10]! + stp x5, x4, [sp, #-0x10]! + stp x3, x2, [sp, #-0x10]! + stp x1, x0, [sp, #-0x10]! + str x30, [sp, #-0x10]! + + ldr x9, [x0, #0x20] + blr x9 + mov x10, x0 + + ldr x30, [sp], #0x10 + ldp x0, x9, [sp], #0x10 + ldp x3, x2, [sp], #0x10 + ldp x5, x4, [sp], #0x10 + ldp x7, x6, [sp], #0x10 + ldr x1, [x9, #0x28] - ldr x9, [x9, #0x20] - ldr x9, [x9] - br x9 + br x10 #else #error No forwarding assembly definition for this arch #endif diff --git a/test/test-imp-forwarding.m b/test/test-imp-forwarding.m index da2ece2..e7bff27 100644 --- a/test/test-imp-forwarding.m +++ b/test/test-imp-forwarding.m @@ -1,9 +1,10 @@ #include "../lib/objc.c" #include <objc/runtime.h> #include <stdio.h> +#import <Foundation/Foundation.h> static void imp1(id self, SEL sel, int a, int b) { - printf("imp1: self=%p sel=%s a=%d b=%d\n", self, sel_getName(sel), a, b); + NSLog(@"imp1: self=%@ sel=%s a=%d b=%d\n", self, sel_getName(sel), a, b); } struct big { @@ -11,16 +12,24 @@ struct big { }; static struct big imp2(id self, SEL sel, int a, int b) { - printf("imp2: self=%p sel=%s a=%d b=%d\n", self, sel_getName(sel), a, b); + NSLog(@"imp2: self=%@ sel=%s a=%d b=%d\n", self, sel_getName(sel), a, b); return (struct big) {{0}}; } +struct big (^test)(id, int) = ^(id self, int a) { + NSLog(@"self=%@ a=%d", self, a); + return (struct big) {{0}}; +}; + int main() { + IMP testi = imp_implementationWithBlock(test); + ((struct big (*)(id, SEL, int)) testi)(@"test", @selector(dumb), 5); IMP old = (IMP) imp1; SEL sel = @selector(some); struct temp_block_literal temp_block = get_temp_block(&old, sel); IMP new = imp_implementationWithBlock((id) &temp_block); ((void (*)(id, SEL, int, int)) new)(@"foo", sel, 1, 2); old = (IMP) imp2; - ((struct big (*)(id, SEL, int, int)) new)(@"bar", sel, 1, 2); + struct big big = ((struct big (*)(id, SEL, int, int)) new)(@"bar", sel, 1, 2); + printf("out? %d\n", big.x[0]); } |