Move program code generation and execution out of program (make it generic)

2 files changed, 307 insertions, 0 deletions

diff --git a/executor/executor.h b/executor/executor.h
new file mode 100644
index 0000000..fdf6e67
--- /dev/null
+++ b/executor/executor.h
@@ -0,0 +1,46 @@
+#ifndef AMAL_EXECUTOR_H
+#define AMAL_EXECUTOR_H
+
+#include "../include/std/misc.h"
+#include "../include/std/types.h"
+#include "../include/std/buffer_view.h"
+
+/*doc(Execution backend)
+Amalgam supports multiple execution backend and they can be implemented with minimal
+effort. The only requirement is implementation of all the functions in executor/executor.h
+and adding the source file with the implementation to the build script. See executor/interpreter/executor.c
+as an example.\
+These functions are then called by amalgam as amalgam parses the amalgam bytecode when `amal_program_run` is called.
+*/
+
+struct amal_executor_impl;
+typedef struct amal_executor amal_executor;
+
+CHECK_RESULT int amal_executor_init(amal_executor **self);
+void amal_executor_deinit(amal_executor *self);
+CHECK_RESULT int amal_executor_run(amal_executor *self);
+
+CHECK_RESULT int amal_exec_nop(amal_executor *self);
+CHECK_RESULT int amal_exec_setz(amal_executor *self, u8 dst_reg);
+CHECK_RESULT int amal_exec_mov(amal_executor *self, u8 dst_reg, u8 src_reg);
+CHECK_RESULT int amal_exec_movi(amal_executor *self, u8 dst_reg, i64 imm);
+CHECK_RESULT int amal_exec_movd(amal_executor *self, u8 dst_reg, BufferView data);
+CHECK_RESULT int amal_exec_add(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2);
+CHECK_RESULT int amal_exec_sub(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2);
+CHECK_RESULT int amal_exec_imul(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2);
+CHECK_RESULT int amal_exec_mul(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2);
+CHECK_RESULT int amal_exec_idiv(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2);
+CHECK_RESULT int amal_exec_div(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2);
+CHECK_RESULT int amal_exec_push(amal_executor *self, u8 reg);
+CHECK_RESULT int amal_exec_pushi(amal_executor *self, i64 imm);
+CHECK_RESULT int amal_exec_pushd(amal_executor *self, BufferView data);
+/*CHECK_RESULT int amal_exec_call(u8 dst_reg, BufferView data);
+CHECK_RESULT int amal_exec_callr(u8 dst_reg, BufferView data);*/
+CHECK_RESULT int amal_exec_cmp(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2);
+CHECK_RESULT int amal_exec_jz(amal_executor *self, u8 dst_reg, i16 offset);
+CHECK_RESULT int amal_exec_jmp(amal_executor *self, i16 offset);
+CHECK_RESULT int amal_exec_ret(amal_executor *self);
+CHECK_RESULT int amal_exec_func_start(amal_executor *self, u16 num_regs);
+CHECK_RESULT int amal_exec_func_end(amal_executor *self);
+
+#endif
diff --git a/executor/x86_64/executor.c b/executor/x86_64/executor.c
new file mode 100644
index 0000000..b53ccea
--- /dev/null
+++ b/executor/x86_64/executor.c
@@ -0,0 +1,261 @@
+#include "../executor.h"
+#include "../../include/std/alloc.h"
+#include "asm.h"
+#include <assert.h>
+
+/*
+    TODO: Currently almost all operations are performed on memory. This should be optimized
+    to take advantage of registers.
+
+    TODO: Operations with memory registers could access outside the stack. Should this be checked?
+*/
+
+typedef struct {
+    Asm asm;
+} amal_executor_impl;
+
+#define IMPL \
+    amal_executor_impl *impl; \
+    impl = (amal_executor_impl*)self;
+
+#define get_register_stack_offset(reg) -(i32)(reg * (int)sizeof(usize) + (int)sizeof(usize))
+
+static i64 abs_i64(i64 value) {
+    return value >= 0 ? value : -value;
+}
+
+int amal_executor_init(amal_executor **self) {
+    amal_executor_impl **impl;
+    return_if_error(am_malloc(sizeof(amal_executor_impl), (void**)self));
+    impl = (amal_executor_impl**)self;
+    return asm_init(&(*impl)->asm);
+}
+
+void amal_executor_deinit(amal_executor *self) {
+    IMPL
+    asm_deinit(&impl->asm);
+    am_free(impl);
+}
+
+int amal_executor_run(amal_executor *self) {
+    IMPL
+    return asm_execute(&impl->asm);
+}
+
+int amal_exec_nop(amal_executor *self) {
+    IMPL
+    return asm_nop(&impl->asm);
+}
+
+int amal_exec_setz(amal_executor *self, u8 dst_reg) {
+    AsmPtr dst;
+    IMPL
+    asm_ptr_init_disp(&dst, RBP, get_register_stack_offset(dst_reg));
+    return asm_mov_mi(&impl->asm, &dst, 0);
+}
+
+int amal_exec_mov(amal_executor *self, u8 dst_reg, u8 src_reg) {
+    AsmPtr ptr;
+    IMPL
+
+    asm_ptr_init_disp(&ptr, RBP, get_register_stack_offset(src_reg));
+    return_if_error(asm_mov_rm(&impl->asm, RAX, &ptr));
+
+    asm_ptr_init_disp(&ptr, RBP, get_register_stack_offset(dst_reg));
+    return asm_mov_mr(&impl->asm, &ptr, RAX);
+}
+
+int amal_exec_movi(amal_executor *self, u8 dst_reg, i64 imm) {
+    IMPL
+    /* TODO: if @number is a float then use float instructions */
+    if(abs_i64(imm) <= INT32_MAX) {
+        AsmPtr dst;
+        asm_ptr_init_disp(&dst, RBP, get_register_stack_offset(dst_reg));
+        return_if_error(asm_mov_mi(&impl->asm, &dst, imm));
+    } else {
+        AsmPtr dst;
+        asm_ptr_init_disp(&dst, RBP, get_register_stack_offset(dst_reg));
+        return_if_error(asm_mov_ri(&impl->asm, RAX, imm));
+        return_if_error(asm_mov_mr(&impl->asm, &dst, RAX));
+    }
+    return 0;
+}
+
+int amal_exec_movd(amal_executor *self, u8 dst_reg, BufferView data) {
+    AsmPtr dst;
+    IMPL
+
+    asm_ptr_init_disp(&dst, RBP, get_register_stack_offset(dst_reg));
+    return_if_error(asm_mov_ri(&impl->asm, RAX, (uintptr_t)data.data));
+    return asm_mov_mr(&impl->asm, &dst, RAX);
+}
+
+int amal_exec_add(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2) {
+    AsmPtr dst;
+    AsmPtr reg1;
+    AsmPtr reg2;
+    IMPL
+
+    asm_ptr_init_disp(&dst, RBP, get_register_stack_offset(dst_reg));
+    asm_ptr_init_disp(&reg1, RBP, get_register_stack_offset(src_reg1));
+    asm_ptr_init_disp(&reg2, RBP, get_register_stack_offset(src_reg2));
+
+    return_if_error(asm_mov_rm(&impl->asm, RAX, &reg1));
+    return_if_error(asm_mov_rm(&impl->asm, RCX, &reg2));
+    return_if_error(asm_add_rr(&impl->asm, RAX, RCX));
+    return asm_mov_mr(&impl->asm, &dst, RAX);
+}
+
+int amal_exec_sub(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2) {
+    AsmPtr dst;
+    AsmPtr reg1;
+    AsmPtr reg2;
+    IMPL
+
+    asm_ptr_init_disp(&dst, RBP, get_register_stack_offset(dst_reg));
+    asm_ptr_init_disp(&reg1, RBP, get_register_stack_offset(src_reg1));
+    asm_ptr_init_disp(&reg2, RBP, get_register_stack_offset(src_reg2));
+
+    return_if_error(asm_mov_rm(&impl->asm, RAX, &reg1));
+    return_if_error(asm_mov_rm(&impl->asm, RCX, &reg2));
+    return_if_error(asm_sub_rr(&impl->asm, RAX, RCX));
+    return asm_mov_mr(&impl->asm, &dst, RAX);
+}
+
+int amal_exec_imul(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2) {
+    AsmPtr dst;
+    AsmPtr reg1;
+    AsmPtr reg2;
+    IMPL
+
+    asm_ptr_init_disp(&dst, RBP, get_register_stack_offset(dst_reg));
+    asm_ptr_init_disp(&reg1, RBP, get_register_stack_offset(src_reg1));
+    asm_ptr_init_disp(&reg2, RBP, get_register_stack_offset(src_reg2));
+
+    return_if_error(asm_mov_rm(&impl->asm, RAX, &reg1));
+    return_if_error(asm_mov_rm(&impl->asm, RCX, &reg2));
+    return_if_error(asm_imul_rr(&impl->asm, RAX, RCX));
+    return asm_mov_mr(&impl->asm, &dst, RAX);
+}
+
+int amal_exec_mul(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2) {
+    (void)self;
+    (void)dst_reg;
+    (void)src_reg1;
+    (void)src_reg2;
+    /* TODO: Implement! */
+    #if 0
+    AsmPtr dst;
+    AsmPtr reg1;
+    AsmPtr reg2;
+
+    asm_ptr_init_disp(&dst, RBP, -(i32)get_register_at_offset(0));
+    asm_ptr_init_disp(&reg1, RBP, -(i32)get_register_at_offset(1));
+    asm_ptr_init_disp(&reg2, RBP, -(i32)get_register_at_offset(2));
+
+    return_if_error(asm_mov_rm(&self->asm, RAX, &reg1));
+    return_if_error(asm_mov_rm(&self->asm, RCX, &reg2));
+    return_if_error(asm_mul_rr(&self->asm, RAX, RCX));
+    return_if_error(asm_mov_mr(&self->asm, &dst, RAX));
+    #endif
+    return 0;
+}
+
+int amal_exec_idiv(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2) {
+    (void)self;
+    (void)dst_reg;
+    (void)src_reg1;
+    (void)src_reg2;
+    /* TODO: Implement! */
+    return 0;
+}
+
+int amal_exec_div(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2) {
+    (void)self;
+    (void)dst_reg;
+    (void)src_reg1;
+    (void)src_reg2;
+    /* TODO: Implement! */
+    return 0;
+}
+
+int amal_exec_push(amal_executor *self, u8 reg) {
+    (void)self;
+    (void)reg;
+    /* TODO: Implement! */
+    return 0;
+}
+
+int amal_exec_pushi(amal_executor *self, i64 imm) {
+    (void)self;
+    (void)imm;
+    /* TODO: Implement! */
+    return 0;
+}
+
+int amal_exec_pushd(amal_executor *self, BufferView data) {
+    (void)self;
+    (void)data;
+    /* TODO: Implement! */
+    return 0;
+}
+
+/*int amal_exec_call(u8 dst_reg, BufferView data);
+int amal_exec_callr(u8 dst_reg, BufferView data);*/
+int amal_exec_cmp(amal_executor *self, u8 dst_reg, u8 src_reg1, u8 src_reg2) {
+    (void)self;
+    (void)dst_reg;
+    (void)src_reg1;
+    (void)src_reg2;
+    /* TODO: Implement! */
+    return 0;
+}
+
+int amal_exec_jz(amal_executor *self, u8 dst_reg, i16 offset) {
+    (void)self;
+    (void)dst_reg;
+    (void)offset;
+    /* TODO: Implement! */
+    return 0;
+}
+
+int amal_exec_jmp(amal_executor *self, i16 offset) {
+    (void)self;
+    (void)offset;
+    /* TODO: Implement! */
+    return 0;
+}
+
+int amal_exec_ret(amal_executor *self) {
+    (void)self;
+    /* TODO: Implement! */
+    assert(bool_false && "TODO: Implement RET. RET needs to restore the stack before returning");
+    return 0;
+}
+
+int amal_exec_func_start(amal_executor *self, u16 num_regs) {
+    /*
+        TODO: Validate stack size, or maybe remove all validation? do we really need validation?
+        If we need security, we could fork the process instead.
+    */
+
+    /*
+        Some registers need to be preserved before entering a function scope and these registers are different on different platforms.
+        32-bit: EBX, ESI, EDI, EBP
+        64-bit Windows: RBX, RSI, RDI, RBP, R12-R15, XMM6-XMM15
+        64-bit Linux,BSD,Mac: RBX, RBP, R12-R15
+    */
+    IMPL
+    return_if_error(asm_pushr(&impl->asm, RBX));
+    return_if_error(asm_pushr(&impl->asm, RBP));
+    return_if_error(asm_mov_rr(&impl->asm, RBP, RSP));
+    return asm_sub_rm64_imm(&impl->asm, RSP, num_regs * sizeof(usize));
+}
+
+int amal_exec_func_end(amal_executor *self) {
+    IMPL
+    return_if_error(asm_mov_rr(&impl->asm, RSP, RBP));
+    return_if_error(asm_popr(&impl->asm, RBP));
+    return_if_error(asm_popr(&impl->asm, RBX));
+    return asm_ret(&impl->asm, 0);
+}