02d830c035
This patch introduces the MICROPY_ENABLE_PYSTACK option (disabled by default) which enables a "Python stack" that allows to allocate and free memory in a scoped, or Last-In-First-Out (LIFO) way, similar to alloca(). A new memory allocation API is introduced along with this Py-stack. It includes both "local" and "nonlocal" LIFO allocation. Local allocation is intended to be equivalent to using alloca(), whereby the same function must free the memory. Nonlocal allocation is where another function may free the memory, so long as it's still LIFO. Follow-up patches will convert all uses of alloca() and VLA to the new scoped allocation API. The old behaviour (using alloca()) will still be available, but when MICROPY_ENABLE_PYSTACK is enabled then alloca() is no longer required or used. The benefits of enabling this option are (or will be once subsequent patches are made to convert alloca()/VLA): - Toolchains without alloca() can use this feature to obtain correct and efficient scoped memory allocation (compared to using the heap instead of alloca(), which is slower). - Even if alloca() is available, enabling the Py-stack gives slightly more efficient use of stack space when calling nested Python functions, due to the way that compilers implement alloca(). - Enabling the Py-stack with the stackless mode allows for even more efficient stack usage, as well as retaining high performance (because the heap is no longer used to build and destroy stackless code states). - With Py-stack and stackless enabled, Python-calling-Python is no longer recursive in the C mp_execute_bytecode function. The micropython.pystack_use() function is included to measure usage of the Python stack.
142 lines
5.0 KiB
C
142 lines
5.0 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2013-2017 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "py/mpstate.h"
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#if !MICROPY_NLR_SETJMP && defined(__x86_64__)
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#undef nlr_push
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// x86-64 callee-save registers are:
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// rbx, rbp, rsp, r12, r13, r14, r15
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#if defined(_WIN32) || defined(__CYGWIN__)
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#define NLR_OS_WINDOWS 1
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#else
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#define NLR_OS_WINDOWS 0
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#endif
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__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);
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unsigned int nlr_push(nlr_buf_t *nlr) {
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(void)nlr;
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#if NLR_OS_WINDOWS
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__asm volatile (
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"movq (%rsp), %rax \n" // load return %rip
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"movq %rax, 16(%rcx) \n" // store %rip into nlr_buf
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"movq %rbp, 24(%rcx) \n" // store %rbp into nlr_buf
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"movq %rsp, 32(%rcx) \n" // store %rsp into nlr_buf
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"movq %rbx, 40(%rcx) \n" // store %rbx into nlr_buf
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"movq %r12, 48(%rcx) \n" // store %r12 into nlr_buf
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"movq %r13, 56(%rcx) \n" // store %r13 into nlr_buf
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"movq %r14, 64(%rcx) \n" // store %r14 into nlr_buf
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"movq %r15, 72(%rcx) \n" // store %r15 into nlr_buf
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"movq %rdi, 80(%rcx) \n" // store %rdr into nlr_buf
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"movq %rsi, 88(%rcx) \n" // store %rsi into nlr_buf
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"jmp nlr_push_tail \n" // do the rest in C
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);
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#else
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__asm volatile (
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#if defined(__APPLE__) || defined(__MACH__)
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"pop %rbp \n" // undo function's prelude
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#endif
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"movq (%rsp), %rax \n" // load return %rip
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"movq %rax, 16(%rdi) \n" // store %rip into nlr_buf
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"movq %rbp, 24(%rdi) \n" // store %rbp into nlr_buf
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"movq %rsp, 32(%rdi) \n" // store %rsp into nlr_buf
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"movq %rbx, 40(%rdi) \n" // store %rbx into nlr_buf
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"movq %r12, 48(%rdi) \n" // store %r12 into nlr_buf
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"movq %r13, 56(%rdi) \n" // store %r13 into nlr_buf
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"movq %r14, 64(%rdi) \n" // store %r14 into nlr_buf
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"movq %r15, 72(%rdi) \n" // store %r15 into nlr_buf
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#if defined(__APPLE__) || defined(__MACH__)
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"jmp _nlr_push_tail \n" // do the rest in C
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#else
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"jmp nlr_push_tail \n" // do the rest in C
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#endif
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);
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#endif
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return 0; // needed to silence compiler warning
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}
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__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr) {
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nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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nlr->prev = *top;
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MP_NLR_SAVE_PYSTACK(nlr);
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*top = nlr;
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return 0; // normal return
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}
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void nlr_pop(void) {
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nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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*top = (*top)->prev;
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}
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NORETURN void nlr_jump(void *val) {
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nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
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nlr_buf_t *top = *top_ptr;
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if (top == NULL) {
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nlr_jump_fail(val);
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}
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top->ret_val = val;
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MP_NLR_RESTORE_PYSTACK(top);
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*top_ptr = top->prev;
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__asm volatile (
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"movq %0, %%rcx \n" // %rcx points to nlr_buf
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#if NLR_OS_WINDOWS
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"movq 88(%%rcx), %%rsi \n" // load saved %rsi
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"movq 80(%%rcx), %%rdi \n" // load saved %rdr
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#endif
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"movq 72(%%rcx), %%r15 \n" // load saved %r15
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"movq 64(%%rcx), %%r14 \n" // load saved %r14
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"movq 56(%%rcx), %%r13 \n" // load saved %r13
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"movq 48(%%rcx), %%r12 \n" // load saved %r12
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"movq 40(%%rcx), %%rbx \n" // load saved %rbx
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"movq 32(%%rcx), %%rsp \n" // load saved %rsp
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"movq 24(%%rcx), %%rbp \n" // load saved %rbp
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"movq 16(%%rcx), %%rax \n" // load saved %rip
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"movq %%rax, (%%rsp) \n" // store saved %rip to stack
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"xorq %%rax, %%rax \n" // clear return register
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"inc %%al \n" // increase to make 1, non-local return
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"ret \n" // return
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: // output operands
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: "r"(top) // input operands
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: // clobbered registers
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);
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for (;;); // needed to silence compiler warning
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}
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#endif // !MICROPY_NLR_SETJMP && defined(__x86_64__)
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