vmir.c

/*
 * Copyright (c) 2016 Lonelycoder AB
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#define _GNU_SOURCE

#include <setjmp.h>
#include <string.h>
#include <stdarg.h>
#include <inttypes.h>
#include <sys/queue.h>
#include <assert.h>
#include <sys/param.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>

#include "bitcode.h"

#include <time.h>
#include <sys/time.h>

#include "vmir.h"

// #define VM_TRACE

#if defined(__SANITIZE_ADDRESS__) && !defined(VM_DONT_USE_COMPUTED_GOTO)
#define VM_DONT_USE_COMPUTED_GOTO
#endif

#if defined(VM_TRACE) && !defined(VM_DONT_USE_COMPUTED_GOTO)
#define VM_DONT_USE_COMPUTED_GOTO
#endif

#if defined(VM_TRACE)
#undef VM_NO_STACK_FRAME
#endif



#ifndef VM_NO_STACK_FRAME
static void vmir_traceback(struct ir_unit *iu, const char *info);
#endif

#ifdef VM_TRACE
static void vmir_access_violation(struct ir_unit *iu, const void *p,
                                  const char *func);
static void vmir_access_trap(struct ir_unit *iu, const void *p,
                             const char *func);
#endif

#include "vmir_support.c"
#include "vmir_bitstream.c"


TAILQ_HEAD(ir_abbrev_queue, ir_abbrev);
LIST_HEAD(ir_blockinfo_list, ir_blockinfo);


LIST_HEAD(ir_attr_list, ir_attr);

/**
 *
 */
typedef struct ir_blockinfo {
  LIST_ENTRY(ir_blockinfo) ib_link;
  int ib_id;
  int ib_num_abbrevs;
  struct ir_abbrev_queue ib_abbrevs;
} ir_blockinfo_t;


typedef struct ir_block {
  LIST_ENTRY(ir_block) ib_link;
  struct ir_abbrev_queue ib_scoped_abbrevs;
  ir_blockinfo_t *ib_blockinfo;
} ir_block_t;


LIST_HEAD(ir_block_list, ir_block);

/**
 *
 */
typedef struct ir_valuetype {
  int value;
  int type;
} ir_valuetype_t;



struct ir_unit;

typedef void (rec_handler_t)(struct ir_unit *iu, int op,
                             unsigned int argc, const int64_t *argv);

VECTOR_HEAD(ir_op_vector, struct ir_op);
VECTOR_HEAD(ir_attrset_vector, struct ir_attrset);
VECTOR_HEAD(ir_type_vector, struct ir_type);
VECTOR_HEAD(ir_value_vector, struct ir_value *);
VECTOR_HEAD(ir_instrumentation_vector, struct ir_instrumentation);

TAILQ_HEAD(ir_bb_queue, ir_bb);
TAILQ_HEAD(ir_function_queue, ir_function);
TAILQ_HEAD(ir_instr_queue, ir_instr);

LIST_HEAD(ir_bb_list, ir_bb);
LIST_HEAD(ir_bb_edge_list, ir_bb_edge);
LIST_HEAD(ir_value_instr_list, ir_value_instr);


typedef struct vmir_exception {
  uint32_t exception;
  uint32_t type_info;
  uint32_t uncaught;
  uint32_t caught;
} vmir_exception_t;



/**
 * Translation unit
 */

typedef int (vm_function_t)(void *ret,
                            const void *regs,
                            struct ir_unit *iu,
                            void *hostmem);

struct ir_unit {
  vmir_function_resolver_t iu_external_function_resolver;

  void *iu_mem_low;
  void *iu_mem_high;
  void *iu_data_breakpoint;

  void *iu_mem;
  void **iu_vm_funcs;
  vm_function_t **iu_function_table;
  jmp_buf *iu_err_jmpbuf;
  int iu_exit_code;
  void *iu_opaque;
  void *iu_jit_mem;
  int iu_jit_mem_alloced;
  int iu_jit_ptr;
  uint32_t iu_jit_cpuflags;

  enum {
    VMIR_BITCODE,
    VMIR_WASM,
  } iu_mode;

  vmir_exception_t iu_exception;

  const struct vm_frame *iu_current_frame;
  char *iu_traced_function;

  uint32_t iu_data_ptr;
  uint32_t iu_heap_start;
  void *iu_heap;
  uint32_t iu_heap_usage;
  uint32_t iu_rsize;
  uint32_t iu_asize;
  uint32_t iu_memsize;

  uint32_t iu_stack_stash;

  struct vFILE *iu_stdin;
  struct vFILE *iu_stdout;
  struct vFILE *iu_stderr;
  const vmir_fsops_t *iu_fsops;
  VECTOR_HEAD(, struct vmir_fd) iu_vfds;
  int iu_vfd_free;  // Point to first free FD (-1 == nothing free)
  LIST_HEAD(, vFILE) iu_vfiles;
  char *iu_strtok_tmp;




  uint32_t iu_debug_flags;
  uint32_t iu_debug_flags_func;
  char *iu_debugged_function;
  struct ir_instrumentation_vector iu_instrumentation;

  char *iu_triple;
  int iu_version;

  struct ir_blockinfo_list iu_blockinfos;
  struct ir_block_list iu_blocks;

  struct ir_attr_list iu_attribute_groups;
  struct ir_attrset_vector iu_attrsets;

  struct ir_type_vector iu_types;

  struct ir_value_vector iu_values;
  int iu_next_value;
  int iu_first_func_value;

  char *iu_current_struct_name;

  struct ir_function_queue iu_functions_with_bodies;

  int iu_current_type;

  struct ir_function *iu_current_function;
  struct ir_bb *iu_current_bb;

#define IU_MAX_TMP_STR 32
  char *iu_tmp_str[IU_MAX_TMP_STR];
  int iu_tmp_str_ptr;

  VECTOR_HEAD(, struct ir_function *) iu_functions;
  VECTOR_HEAD(, struct ir_initializer) iu_initializers;

  VECTOR_HEAD(, int) iu_branch_fixups;
  VECTOR_HEAD(, int) iu_jit_vmbb_fixups;
  VECTOR_HEAD(, int) iu_jit_branch_fixups;
  VECTOR_HEAD(, int) iu_jit_bb_to_addr_fixups;

  int iu_types_created;

  // Parser

  jmp_buf iu_parser_jmp;

  void *iu_text_alloc;
  void *iu_text_ptr;
  size_t iu_text_alloc_memsize;

  VECTOR_HEAD(, int64_t) iu_argv;

  char        iu_err_buf[256];
  const char *iu_err_file;
  int         iu_err_line;
  int         iu_failed;
  int         iu_vstoffset;

  // WASM

  VECTOR_HEAD(, int) iu_wasm_type_map;
  VECTOR_HEAD(, ir_valuetype_t) iu_wasm_globalvar_map;
  VECTOR_HEAD(, int) iu_wasm_functions;
  VECTOR_HEAD(, ir_valuetype_t) iu_wasm_value_stack;
  VECTOR_HEAD(, struct ir_bb *) iu_wasm_cfg_stack;

  // Stats

  vmir_stats_t iu_stats;
  vmir_logger_t *iu_logger;
  vmir_log_level_t iu_log_level;
};

static uint32_t
vmir_host_to_vmaddr(ir_unit_t *iu, void *ptr)
{
  if(ptr == NULL)
    return 0;
  return ptr - iu->iu_mem;
}

/**
 * Attribute
 */
typedef struct ir_attr {
  LIST_ENTRY(ir_attr) ia_link;

  uint32_t ia_group_id;
  uint32_t ia_index;

  uint64_t ia_flags;

} ir_attr_t;


/**
 * Attribute Set
 */
typedef struct ir_attrset {
  int ias_size;
  const ir_attr_t **ias_list;
} ir_attrset_t;


/**
 *
 */
struct ir_function {
  TAILQ_ENTRY(ir_function) if_body_link;
  unsigned int if_type;
  char *if_name;
  char if_isproto;
  char if_used;
  char if_full_jit;
  int if_regframe_size; // Size of all temporary registers
  int if_callarg_size;  // Size of all (non vararg) arguments
  int if_gfid;          // Global function id
  int if_vmop;          // Set if function maps directly to a VM opcode
  int if_vmop_args;     // Number of args the vmop expects

  int if_num_bbs;
  struct ir_bb_queue if_bbs;
  struct ir_bb_edge_list if_edges;

  void *if_vm_text;
  int if_vm_text_size;

  vm_function_t *if_ext_func;

  struct ir_instr_backref *if_instr_backrefs;
  int if_instr_backref_size;

  int if_jit_offset;

#ifndef VM_NO_STACK_FRAME
  int if_peak_stack_use;
#endif
};


/**
 *
 */
typedef struct ir_globalvar {
  TAILQ_ENTRY(ir_globalvar) ig_unit_link;
  unsigned int ig_type;
  char *ig_name;
  uint32_t ig_addr;
  uint32_t ig_size;
} ir_globalvar_t;


/**
 *
 */
typedef struct ir_initializer {
  int ii_globalvar;
  int ii_constant;
} ir_initializer_t;


/**
 *
 */
typedef struct ir_bb {
  TAILQ_ENTRY(ir_bb) ib_link;
  struct ir_instr_queue ib_instrs;
  int ib_text_offset;
  int ib_jit_offset;
  int ib_id;
  uint8_t ib_mark;
  uint8_t ib_jit;
  uint8_t ib_only_jit_sucessors;
  uint8_t ib_force_jit_entrypoint;

  struct ir_bb_edge_list ib_incoming_edges;
  struct ir_bb_edge_list ib_outgoing_edges;

  LIST_ENTRY(ir_bb) ib_traversal_link; // Temporary for graph traversal

  char *ib_name;

} ir_bb_t;


/**
 *
 */
typedef struct ir_bb_edge {
  LIST_ENTRY(ir_bb_edge) ibe_from_link;
  LIST_ENTRY(ir_bb_edge) ibe_to_link;
  LIST_ENTRY(ir_bb_edge) ibe_function_link;
  ir_bb_t *ibe_from;
  ir_bb_t *ibe_to;
} ir_bb_edge_t;


/**
 *
 */
typedef struct ir_instrumentation {
  struct ir_function *ii_func;
  int ii_bb;
  int ii_instructions;
  int64_t ii_count;
} ir_instrumentation_t;




/**
 *
 */
typedef enum {
  // Instructions defined in bitcode
  IR_IC_UNREACHABLE,
  IR_IC_RET,
  IR_IC_BINOP,
  IR_IC_CAST,
  IR_IC_LOAD,
  IR_IC_STORE,
  IR_IC_GEP,
  IR_IC_CMP2,
  IR_IC_BR,
  IR_IC_PHI,
  IR_IC_CALL,
  IR_IC_INVOKE, // http://llvm.org/docs/LangRef.html#invoke-instruction
  IR_IC_SWITCH,
  IR_IC_ALLOCA,
  IR_IC_SELECT,
  IR_IC_VAARG,
  IR_IC_EXTRACTVAL,
  IR_IC_INSERTVAL, // http://llvm.org/docs/LangRef.html#insertvalue-instruction
  IR_IC_LANDINGPAD, // http://llvm.org/docs/LangRef.html#landingpad-instruction
  IR_IC_RESUME, // http://llvm.org/docs/LangRef.html#resume-instruction

  // VMIR special instructions
  IR_IC_LEA,
  IR_IC_MOVE,
  IR_IC_VMOP,
  IR_IC_STACKCOPY,
  IR_IC_STACKSHRINK,
  IR_IC_CMP_BRANCH,
  IR_IC_CMP_SELECT,
  IR_IC_MLA,
} instr_class_t;


/**
 *
 */
typedef struct ir_instr {
  TAILQ_ENTRY(ir_instr) ii_link;
  struct ir_bb *ii_bb;
  ir_valuetype_t *ii_rets;
  struct ir_value_instr_list ii_values;
  instr_class_t ii_class;
  ir_valuetype_t ii_ret;

  uint32_t *ii_liveness; /* Points to three consecutive bitfields used for
                          * during liveness analysis.
                          * [out] [gen] [in]
                          * The size of these bitfields are given by the number
                          * of temporaries in each function
                          */
  struct ir_bb **ii_succ;
  SLIST_ENTRY(ir_instr) ii_tmplink;
  int16_t ii_num_succ;
  uint8_t ii_jit;
} ir_instr_t;


static void
vmir_log(ir_unit_t *iu, vmir_log_level_t level, const char *fmt, ...)
{
  if(level > iu->iu_log_level)
    return;

  va_list ap;
  char tmp[1024];
  va_start(ap, fmt);
  vsnprintf(tmp, sizeof(tmp), fmt, ap);
  va_end(ap);

  if(iu->iu_logger) {
    iu->iu_logger(iu, level, tmp);
  } else {
    printf("%s\n", tmp);
  }
}


void
vmir_set_logger(ir_unit_t *iu, vmir_logger_t *logger)
{
  iu->iu_logger = logger;
}

void
vmir_set_log_level(ir_unit_t *iu, vmir_log_level_t level)
{
  iu->iu_log_level = level;
}

static void type_print_list(ir_unit_t *iu);
static void value_print_list(ir_unit_t *iu);
static void function_print(ir_unit_t *iu, ir_function_t *f, const char *what);

#define parser_error(iu, fmt...) \
  parser_error0(iu, __FILE__, __LINE__, fmt)

/**
 *
 */
static void __attribute__((noreturn))
parser_error0(ir_unit_t *iu, const char *file, int line,
              const char *fmt, ...)
{
  va_list ap;
  va_start(ap, fmt);
  vsnprintf(iu->iu_err_buf, sizeof(iu->iu_err_buf), fmt, ap);
  va_end(ap);
  iu->iu_err_file = file;
  iu->iu_err_line = line;

  vmir_log(iu, VMIR_LOG_ERROR, "Parser error: %s:%d : %s",
           file, line, iu->iu_err_buf);

  if(iu->iu_failed) {
    printf("Double failure\n");
  } else {
    iu->iu_failed = 1;
  }

  longjmp(iu->iu_parser_jmp, 1);
}

/**
 *
 */
static char * __attribute__((warn_unused_result))
tmpstr(ir_unit_t *iu, int len)
{
  int idx = (iu->iu_tmp_str_ptr++) & (IU_MAX_TMP_STR - 1);
  free(iu->iu_tmp_str[idx]);
  iu->iu_tmp_str[idx] = malloc(len + 1);
  iu->iu_tmp_str[idx][len] = 0;
  return iu->iu_tmp_str[idx];
}


/**
 *
 */
static int __attribute__((warn_unused_result))
addstr(char **dst, const char *str)
{
  int len = strlen(str);
  if(dst != NULL) {
    memcpy(*dst, str, len);
    *dst += len;
  }
  return len;
}


/**
 *
 */
static int __attribute__((warn_unused_result))
addstrf(char **dst, const char *fmt, ...)
{
  int len = 0;
  va_list ap;
  va_start(ap, fmt);
  if(dst == NULL) {
    len = vsnprintf(NULL, 0, fmt, ap);
  } else {
    len = vsprintf(*dst, fmt, ap);
    *dst += len;
  }
  va_end(ap);
  return len;
}

#include "vmir_mem.c"
#include "vmir_type.c"
#include "vmir_value.c"
#include "vmir_vm.h"
#include "vmir_instr.c"
#include "vmir_function.c"
#if defined(__arm__) && (defined(__linux__) || defined(__ANDROID__))
#include "vmir_jit_arm.c"
#endif
#include "vmir_transform.c"
#include "vmir_vm.c"
#include "vmir_libc.c"

#include "vmir_bitcode_instr.c"
#include "vmir_bitcode_parser.c"

#include "vmir_wasm_parser.c"


/**
 *
 */
static void
initialize_global(ir_unit_t *iu, void *addr,
                  int dstty_index, const ir_value_t *c)
{
  int x, size;
  ir_valuetype_t *ivt;
  const ir_type_t *dstty = type_get(iu, dstty_index);

  switch(dstty->it_code) {
  case IR_TYPE_INT1:
  case IR_TYPE_INT8:
    mem_wr8(addr, value_get_const32(iu, c), iu);
    break;
  case IR_TYPE_INT16:
    mem_wr16(addr, value_get_const32(iu, c), iu);
    break;
  case IR_TYPE_INT32:
  case IR_TYPE_FLOAT:
    mem_wr32(addr, value_get_const32(iu, c), iu);
    break;
  case IR_TYPE_INT64:
  case IR_TYPE_DOUBLE:
    mem_wr64(addr, value_get_const64(iu, c), iu);
    break;

  case IR_TYPE_POINTER:
    switch(c->iv_class) {
    case IR_VC_GLOBALVAR:
    case IR_VC_CONSTANT:
      mem_wr32(addr, value_get_const32(iu, c), iu);
      break;
    case IR_VC_FUNCTION:
      mem_wr32(addr, value_function_addr(c), iu);
      break;

    default:
      parser_error(iu, "Unable to initialize pointer from value class %d",
                   c->iv_class);
    }
    break;

  case IR_TYPE_ARRAY:
    size = type_sizeof(iu, dstty_index);
    switch(c->iv_class) {
    case IR_VC_DATA:
      memcpy(addr, c->iv_data, size);
      break;
    case IR_VC_ZERO_INITIALIZER:
      memset(addr, 0, size);
      break;
    case IR_VC_AGGREGATE:
      // Iterate over all elements
      x = dstty->it_array.num_elements;
      assert(c->iv_num_values == x);
      ivt = c->iv_data;
      for(int i = 0; i < x; i++) {
        ir_value_t *subvalue = value_get(iu, ivt[i].value);
        initialize_global(iu, addr, dstty->it_array.element_type, subvalue);
        addr += type_sizeof(iu, dstty->it_array.element_type);
      }

      break;
    default:
      parser_error(iu, "Unable to initialize array from value class %d",
                   c->iv_class);
    }
    break;

  case IR_TYPE_STRUCT:
    size = type_sizeof(iu, dstty_index);
    switch(c->iv_class) {
    case IR_VC_ZERO_INITIALIZER:
      memset(addr, 0, size);
      break;
    case IR_VC_AGGREGATE:
      // Iterate over all elements
      x = dstty->it_struct.num_elements;
      assert(c->iv_num_values == x);
      ivt = c->iv_data;
      for(int i = 0; i < x; i++) {
        ir_value_t *subvalue = value_get(iu, ivt[i].value);
        initialize_global(iu, addr + dstty->it_struct.elements[i].offset,
                          dstty->it_struct.elements[i].type, subvalue);
      }
      break;
    default:
      parser_error(iu, "Unable to initialize struct from value class %d",
                   c->iv_class);
    }
    break;

  default:
    parser_error(iu, "Unable to initialize global 0x%x (%s) from %s",
                 addr, type_str(iu, dstty),
                 type_str_index(iu, c->iv_type));
  }
}


/**
 *
 */
static void
initialize_globals(ir_unit_t *iu, void *mem)
{
  for(int i = 0; i < VECTOR_LEN(&iu->iu_initializers); i++) {
    ir_initializer_t *ii = &VECTOR_ITEM(&iu->iu_initializers, i);
    const ir_value_t *gv = value_get(iu, ii->ii_globalvar);
    const ir_value_t *c  = value_get(iu, ii->ii_constant);
    const ir_globalvar_t *ig = gv->iv_gvar;
#if 0
    printf("Initializing global @ 0x%08x + 0x%08x '%s' with '%s'\n",
           ig->ig_addr, ig->ig_size,
           value_str_id(iu, ii->ii_globalvar),
           value_str_id(iu, ii->ii_constant));
#endif
    initialize_global(iu, mem + ig->ig_addr, ig->ig_type, c);
  }
}


/**
 *
 */
static void
iu_cleanup(ir_unit_t *iu)
{
  value_resize(iu, 0);

  VECTOR_CLEAR(&iu->iu_argv);
  VECTOR_CLEAR(&iu->iu_branch_fixups);
  VECTOR_CLEAR(&iu->iu_jit_vmbb_fixups);
  VECTOR_CLEAR(&iu->iu_jit_branch_fixups);
  VECTOR_CLEAR(&iu->iu_jit_bb_to_addr_fixups);
  VECTOR_CLEAR(&iu->iu_initializers);
  VECTOR_CLEAR(&iu->iu_values);

  VECTOR_CLEAR(&iu->iu_wasm_type_map);
  VECTOR_CLEAR(&iu->iu_wasm_globalvar_map);
  VECTOR_CLEAR(&iu->iu_wasm_functions);
  VECTOR_CLEAR(&iu->iu_wasm_value_stack);
  VECTOR_CLEAR(&iu->iu_wasm_cfg_stack);

  ir_attr_t *ia;
  while((ia = LIST_FIRST(&iu->iu_attribute_groups)) != NULL) {
    LIST_REMOVE(ia, ia_link);
    free(ia);
  }

  for(int i = 0; i < VECTOR_LEN(&iu->iu_attrsets); i++) {
    ir_attrset_t *ias = &VECTOR_ITEM(&iu->iu_attrsets, i);
    free(ias->ias_list);
  }
  VECTOR_CLEAR(&iu->iu_attrsets);

  iu->iu_current_bb = NULL;
  iu->iu_current_function = NULL;

  for(int i = 0; i < IU_MAX_TMP_STR; i++) {
    free(iu->iu_tmp_str[i]);
    iu->iu_tmp_str[i] = NULL;
  }

  ir_blockinfo_t *ib;
  while((ib = LIST_FIRST(&iu->iu_blockinfos)) != NULL)
    blockinfo_destroy(ib);
}


/**
 *
 */
void
vmir_destroy(ir_unit_t *iu)
{
  libc_terminate(iu);

  for(int i = 0; i < VECTOR_LEN(&iu->iu_functions); i++) {
    function_destroy(VECTOR_ITEM(&iu->iu_functions, i));
  }

  free(iu->iu_vm_funcs);
  free(iu->iu_function_table);
  VECTOR_CLEAR(&iu->iu_functions);

  for(int i = 0; i < VECTOR_LEN(&iu->iu_types); i++) {
    ir_type_t *it = &VECTOR_ITEM(&iu->iu_types, i);
    type_clean(it);
  }

  VECTOR_CLEAR(&iu->iu_types);

  free(iu->iu_triple);
  free(iu->iu_debugged_function);

  VECTOR_CLEAR(&iu->iu_vfds);
  free(iu);
}


/**
 *
 */
ir_unit_t *
vmir_create(void *membase, uint32_t memsize,
            uint32_t rsize, uint32_t asize,
            void *opaque)
{
  ir_unit_t *iu = calloc(1, sizeof(ir_unit_t));
  iu->iu_log_level = VMIR_LOG_INFO;
  iu->iu_external_function_resolver = vmir_default_external_function_resolver;

  iu->iu_opaque = opaque;
  iu->iu_mem = membase;
  iu->iu_memsize = memsize;
  iu->iu_rsize = rsize;
  iu->iu_asize = asize;
  iu->iu_text_alloc_memsize = 1024 * 1024;
  iu->iu_text_alloc = malloc(iu->iu_text_alloc_memsize);

  iu->iu_mem_low = iu->iu_mem;
  iu->iu_mem_high = iu->iu_mem + memsize;

  return iu;
}

void *
vmir_get_opaque(ir_unit_t *iu)
{
  return iu->iu_opaque;
}


vmir_function_resolver_t vmir_get_external_function_resolver(ir_unit_t *iu)
{
	return iu->iu_external_function_resolver;
}

void vmir_set_external_function_resolver(ir_unit_t *iu, vmir_function_resolver_t fn)
{
	iu->iu_external_function_resolver = fn;
}


/**
 *
 */
static const ir_globalvar_t *
find_globalvar(ir_unit_t *iu, const char *name)
{
  for(int i = 0; i < iu->iu_next_value; i++) {
    ir_value_t *iv = value_get(iu, i);
    if(iv->iv_class != IR_VC_GLOBALVAR)
      continue;
    ir_globalvar_t *ig = iv->iv_gvar;
    if(ig->ig_name != NULL && !strcmp(ig->ig_name, name))
      return ig;
  }
  return NULL;
}


/**
 *
 */
static void
run_global_ctors(ir_unit_t *iu)
{
  const ir_globalvar_t *ig = find_globalvar(iu, "llvm.global_ctors");

  if(ig == NULL)
    return;
  const int ctor_size = 12;
  int num_ctors = ig->ig_size / ctor_size;

  for(int i = 0; i < num_ctors; i++) {
    uint32_t fn = mem_rd32(iu->iu_mem + ig->ig_addr + ctor_size * i + 4, iu);
    if(fn < VECTOR_LEN(&iu->iu_functions)) {
      ir_function_t *f = VECTOR_ITEM(&iu->iu_functions, fn);
      vmir_vm_function_call(iu, f, NULL);
    }
  }
}

/**
 *
 */
int
vmir_load(ir_unit_t *iu, const uint8_t *u8, int len)
{
  bcbitstream_t bs = {0};
  bs.rdata = u8;
  bs.bytes_length = len;


  TAILQ_INIT(&iu->iu_functions_with_bodies);

  if(setjmp(iu->iu_parser_jmp)) {
    iu_cleanup(iu);
    return VMIR_ERR_LOAD_ERROR;
  }

#ifdef VMIR_VM_JIT
  jit_init(iu);
#endif

  const uint32_t magic = read_bits(&bs, 32);
  iu->iu_data_ptr = 4096;
  switch(magic) {

  case 0x6d736100: // WebAssembly
    iu->iu_mode = VMIR_WASM;
    wasm_parse_module(iu, u8 + 4, u8 + len);
    break;

  case 0xdec04342: // LLVM Bitcode
    // WebAssembly need memory at 0. Bitcode don't really.
    ir_parse_blocks(iu, 2, NULL, NULL, &bs);
    break;
  default:
    return VMIR_ERR_NOT_BITCODE;
  }

  free(iu->iu_text_alloc);

#ifdef VMIR_VM_JIT
  jit_seal_code(iu);
#endif
  iu->iu_heap_start = VMIR_ALIGN(iu->iu_data_ptr, 4096);
  iu->iu_stats.data_size = iu->iu_heap_start;

  vmir_heap_init(iu);

  initialize_globals(iu, iu->iu_mem);

  libc_initialize(iu);

  iu->iu_vm_funcs  = calloc(VECTOR_LEN(&iu->iu_functions), sizeof(void *));
  iu->iu_function_table = calloc(VECTOR_LEN(&iu->iu_functions), sizeof(void *));
  for(int i = 0; i < VECTOR_LEN(&iu->iu_functions); i++) {
    ir_function_t *f = VECTOR_ITEM(&iu->iu_functions, i);

    iu->iu_vm_funcs[i]  = f->if_vm_text;
    iu->iu_function_table[i] = f->if_ext_func;
    if(f->if_used && f->if_vm_text == NULL && f->if_ext_func == NULL) {
      vmir_log(iu, VMIR_LOG_ERROR, "Function %s() is not defined", f->if_name);
      if(!(iu->iu_debug_flags & VMIR_DBG_IGNORE_UNRESOLVED_FUNCTIONS)) {
        parser_error(iu, "Function %s() is not defined", f->if_name);
      }
    }
  }

  run_global_ctors(iu);

  iu_cleanup(iu);
  return 0;
}


/**
 *
 */
static int
instrumentation_cmp(const ir_instrumentation_t *a,
                    const ir_instrumentation_t *b)
{
  if(a->ii_count * a->ii_instructions < b->ii_count * b->ii_instructions)
    return -1;
  if(a->ii_count * a->ii_instructions > b->ii_count * b->ii_instructions)
    return 1;
  return 0;
}

/**
 *
 */
void
vmir_instrumentation_dump(ir_unit_t *iu)
{
  VECTOR_SORT(&iu->iu_instrumentation, instrumentation_cmp);
  for(int i = 0; i < VECTOR_LEN(&iu->iu_instrumentation); i++) {
    const ir_instrumentation_t *ii = &VECTOR_ITEM(&iu->iu_instrumentation, i);
    printf("%10"PRId64" %10"PRId64" %s.%d\n",
           ii->ii_count,
           ii->ii_count * ii->ii_instructions,
           ii->ii_func->if_name, ii->ii_bb);
  }
}


/**
 *
 */
uint32_t
vmir_mem_copy(ir_unit_t *iu, const void *data, size_t len)
{
  void *hostaddr;
  uint32_t addr = vmir_mem_alloc(iu, len, &hostaddr);
  if(hostaddr != NULL)
    memcpy(hostaddr, data, len);

  return addr;
}


/**
 *
 */
uint32_t
vmir_mem_strdup(ir_unit_t *iu, const char *str)
{
  return vmir_mem_copy(iu, str, strlen(str) + 1);
}


/**
 * Copy argv vector into VM space (at top of alloca stack)
 */
static uint32_t
vmir_argv_copy(ir_unit_t *iu, int argc, char **argv)
{
  void *vm_argv_host;
  uint32_t vm_argv = vmir_mem_alloc(iu, (argc + 1) * sizeof(uint32_t),
                                    &vm_argv_host);

  for(int i = 0; i < argc; i++) {
    uint32_t str = vmir_mem_strdup(iu, argv[i]);
    mem_wr32(vm_argv_host + i * sizeof(uint32_t), str, iu);
  }
  return vm_argv;
}


/**
 *
 */
int
vmir_run(ir_unit_t *iu, int *retptr, int argc, char **argv)
{
  ir_function_t *f;
  f = vmir_find_function(iu, "main");
  if(f == NULL)
    return VM_STOP_BAD_FUNCTION;

  int vm_argv = vmir_argv_copy(iu, argc, argv);

  union {
    uint32_t u32;
    uint64_t u64;
  } ret;

  int r = vmir_vm_function_call(iu, f, &ret, argc, vm_argv);


  if(r == VM_STOP_EXIT)
    ret.u32 = iu->iu_exit_code;

  if(retptr != NULL)
    *retptr = ret.u32;

  switch(r) {
  case 0:
    vmir_log(iu, VMIR_LOG_DEBUG, "Program returned normally: 0x%x", ret.u32);
    break;
  case VM_STOP_EXIT:
    vmir_log(iu, VMIR_LOG_DEBUG, "Program exit(): 0x%x", iu->iu_exit_code);
    break;
  case VM_STOP_ABORT:
    vmir_log(iu, VMIR_LOG_ERROR, "Program abort");
    break;
  case VM_STOP_UNREACHABLE:
    vmir_log(iu, VMIR_LOG_ERROR, "Unreachable instruction");
    break;
  case VM_STOP_BAD_INSTRUCTION:
    vmir_log(iu, VMIR_LOG_ERROR, "Bad instruction");
    break;
  case VM_STOP_BAD_FUNCTION:
    vmir_log(iu, VMIR_LOG_ERROR, "Bad function %d", iu->iu_exit_code);
    break;
  case VM_STOP_UNCAUGHT_EXCEPTION:
    vmir_log(iu, VMIR_LOG_ERROR, "Uncaught exception");
    break;
  }
  return r;
}


/**
 *
 */
void
vmir_set_debug_flags(ir_unit_t *iu, int flags)
{
  iu->iu_debug_flags = flags;
}

/**
 *
 */
void
vmir_set_debugged_function(ir_unit_t *iu, const char *function)
{
  free(iu->iu_debugged_function);
  iu->iu_debugged_function = function ? strdup(function) : NULL;
}


void
vmir_set_traced_function(ir_unit_t *iu, const char *fname)
{
  free(iu->iu_traced_function);
  iu->iu_traced_function = fname ? strdup(fname) : NULL;
}

const vmir_stats_t *
vmir_get_stats(ir_unit_t *iu)
{
  return &iu->iu_stats;
}