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py/asmx86: Change indirect calls to load fun ptr from the native table.

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Instead of storing the function pointer directly in the assembly code.
This makes the generated code more independent of the runtime (so easier to
relocate the code), and reduces the generated code size.
This commit is contained in:
Damien George
2018-10-13 13:59:19 +11:00
parent b7c6f859d0
commit 355eb8eafb
3 changed files with 10 additions and 16 deletions
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18
py/asmx86.c
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@@ -494,7 +494,7 @@ void asm_x86_push_local_addr(asm_x86_t *as, int local_num, int temp_r32)
}
#endif
void asm_x86_call_ind(asm_x86_t *as, void *ptr, mp_uint_t n_args, int temp_r32) {
void asm_x86_call_ind(asm_x86_t *as, size_t fun_id, mp_uint_t n_args, int temp_r32) {
// TODO align stack on 16-byte boundary before the call
assert(n_args <= 5);
if (n_args > 4) {
@@ -512,20 +512,10 @@ void asm_x86_call_ind(asm_x86_t *as, void *ptr, mp_uint_t n_args, int temp_r32)
if (n_args > 0) {
asm_x86_push_r32(as, ASM_X86_REG_ARG_1);
}
#ifdef __LP64__
// We wouldn't run x86 code on an x64 machine. This is here to enable
// testing of the x86 emitter only.
asm_x86_mov_i32_to_r32(as, (int32_t)(int64_t)ptr, temp_r32);
#else
// If we get here, sizeof(int) == sizeof(void*).
asm_x86_mov_i32_to_r32(as, (int32_t)ptr, temp_r32);
#endif
// Load the pointer to the function and make the call
asm_x86_mov_mem32_to_r32(as, ASM_X86_REG_EBP, fun_id * WORD_SIZE, temp_r32);
asm_x86_write_byte_2(as, OPCODE_CALL_RM32, MODRM_R32(2) | MODRM_RM_REG | MODRM_RM_R32(temp_r32));
// this reduces code size by 2 bytes per call, but doesn't seem to speed it up at all
/*
asm_x86_write_byte_1(as, OPCODE_CALL_REL32);
asm_x86_write_word32(as, ptr - (void*)(as->code_base + as->base.code_offset + 4));
*/
// the caller must clean up the stack
if (n_args > 0) {