C++ DECL_INITIAL函数代码示例

static tree build_junk_fn(unsigned id)
{
    char fnname[32] = {0};
    tree decl, resdecl, initial, proto;

    /* Func decl */
    snprintf(fnname, 31, "__func%d", id);
    proto = build_varargs_function_type_list(void_type_node, NULL_TREE);
    decl = build_fn_decl(fnname, proto);
    SET_DECL_ASSEMBLER_NAME(decl, get_identifier(fnname));
    
    printf(TAG "Creating junk function: %s\n", fnname);
   
    /* Result */ 
    resdecl=build_decl(BUILTINS_LOCATION,RESULT_DECL,NULL_TREE,void_type_node);
    DECL_ARTIFICIAL(resdecl) = 1;
    DECL_CONTEXT(resdecl) = decl;
    DECL_RESULT(decl) = resdecl;
    
    /* Initial */
    initial = make_node(BLOCK);
    TREE_USED(initial) = 1;
    DECL_INITIAL(decl) = initial;
    DECL_UNINLINABLE(decl) = 1;
    DECL_EXTERNAL(decl) = 0;
    DECL_PRESERVE_P(decl) = 1;

    /* Func decl */
    TREE_USED(decl) = 1;
    TREE_PUBLIC(decl) = 1;
    TREE_STATIC(decl) = 1;
    DECL_ARTIFICIAL(decl) = 1;

    /* Make the function */
    push_struct_function(decl);
    /* DECL_SAVED_TREE(decl) = gen_junk(); */
    cfun->function_end_locus = BUILTINS_LOCATION;
    gimplify_function_tree(decl);

    /* Update */
    cgraph_add_new_function(decl, false);
    cgraph_mark_needed_node(cgraph_node(decl));
    current_function_decl = NULL_TREE;
    pop_cfun();

    return decl;
}

static tree
make_alias_for_thunk (tree function)
{
  tree alias;
  char buf[256];

#if defined (TARGET_IS_PE_COFF)
  if (DECL_ONE_ONLY (function))
    return function;
#endif

  ASM_GENERATE_INTERNAL_LABEL (buf, "LTHUNK", thunk_labelno);
  thunk_labelno++;
  alias = build_decl (FUNCTION_DECL, get_identifier (buf),
		      TREE_TYPE (function));
  DECL_LANG_SPECIFIC (alias) = DECL_LANG_SPECIFIC (function);
  cxx_dup_lang_specific_decl (alias);
  DECL_CONTEXT (alias) = NULL;
  TREE_READONLY (alias) = TREE_READONLY (function);
  TREE_THIS_VOLATILE (alias) = TREE_THIS_VOLATILE (function);
  TREE_PUBLIC (alias) = 0;
  DECL_INTERFACE_KNOWN (alias) = 1;
  DECL_NOT_REALLY_EXTERN (alias) = 1;
  DECL_THIS_STATIC (alias) = 1;
  DECL_SAVED_FUNCTION_DATA (alias) = NULL;
  DECL_DESTRUCTOR_P (alias) = 0;
  DECL_CONSTRUCTOR_P (alias) = 0;
  DECL_CLONED_FUNCTION (alias) = NULL_TREE;
  DECL_EXTERNAL (alias) = 0;
  DECL_ARTIFICIAL (alias) = 1;
  DECL_NO_STATIC_CHAIN (alias) = 1;
  DECL_PENDING_INLINE_P (alias) = 0;
  DECL_INLINE (alias) = 0;
  DECL_DECLARED_INLINE_P (alias) = 0;
  DECL_DEFERRED_FN (alias) = 0;
  DECL_USE_TEMPLATE (alias) = 0;
  DECL_TEMPLATE_INSTANTIATED (alias) = 0;
  DECL_TEMPLATE_INFO (alias) = NULL;
  DECL_INITIAL (alias) = error_mark_node;
  TREE_ADDRESSABLE (alias) = 1;
  TREE_USED (alias) = 1;
  SET_DECL_ASSEMBLER_NAME (alias, DECL_NAME (alias));
  TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (alias)) = 1;
  if (!flag_syntax_only)
    assemble_alias (alias, DECL_ASSEMBLER_NAME (function));
  return alias;
}

static tree
create_cilk_helper_decl (struct wrapper_data *wd)
{
  char name[20];
  if (wd->type == CILK_BLOCK_FOR)
    sprintf (name, "_cilk_for_" HOST_WIDE_INT_PRINT_DEC, cilk_wrapper_count++);
  else if (wd->type == CILK_BLOCK_SPAWN)
    sprintf (name, "_cilk_spn_" HOST_WIDE_INT_PRINT_DEC, cilk_wrapper_count++);
  else
    gcc_unreachable (); 
  
  clean_symbol_name (name);

  tree fndecl = build_decl (DECL_SOURCE_LOCATION (current_function_decl),
			    FUNCTION_DECL, get_identifier (name), wd->fntype);

  TREE_PUBLIC (fndecl) = 0;
  TREE_STATIC (fndecl) = 1;
  TREE_USED (fndecl) = 1;
  DECL_ARTIFICIAL (fndecl) = 0;
  DECL_IGNORED_P (fndecl) = 0;
  DECL_EXTERNAL (fndecl) = 0;

  DECL_CONTEXT (fndecl) = wd->context; 
  tree block = make_node (BLOCK);
  DECL_INITIAL (fndecl) = block;
  TREE_USED (block) = 1;
  BLOCK_SUPERCONTEXT (block) = fndecl;
  gcc_assert (!DECL_SAVED_TREE (fndecl));

  /* Inlining would defeat the purpose of this wrapper.
     Either it secretly switches stack frames or it allocates
     a stable stack frame to hold function arguments even if
     the parent stack frame is stolen.  */
  DECL_UNINLINABLE (fndecl) = 1;

  tree result_decl = build_decl (UNKNOWN_LOCATION, RESULT_DECL, NULL_TREE, 
				 void_type_node);
  DECL_ARTIFICIAL (result_decl) = 0;
  DECL_IGNORED_P (result_decl) = 1;
  DECL_CONTEXT (result_decl) = fndecl;
  DECL_RESULT (fndecl) = result_decl;
  
  return fndecl;
}

/* Remove node from the varpool.  */
void
varpool_remove_node (varpool_node *node)
{
  tree init;
  varpool_call_node_removal_hooks (node);
  symtab_unregister_node (node);

  /* Because we remove references from external functions before final compilation,
     we may end up removing useful constructors.
     FIXME: We probably want to trace boundaries better.  */
  if (cgraph_state == CGRAPH_LTO_STREAMING)
    ;
  else if ((init = ctor_for_folding (node->decl)) == error_mark_node)
    varpool_remove_initializer (node);
  else
    DECL_INITIAL (node->decl) = init;
  ggc_free (node);
}

static void search_local_strs(bool initexit)
{
	unsigned int i;
	tree var;

	FOR_EACH_LOCAL_DECL(cfun, i, var) {
		tree str, init_val = DECL_INITIAL(var);

		if (init_val == NULL_TREE)
			continue;
		if (strcmp(DECL_NAME_POINTER(var), "__func__"))
			continue;

		str = get_string_cst(init_val);
		gcc_assert(str);

		if (set_init_exit_section(var, initexit) && verbose)
			inform(DECL_SOURCE_LOCATION(var), "initified local var: %s: %s", DECL_NAME_POINTER(current_function_decl), TREE_STRING_POINTER(str));
	}

/* Wrapup a function contained in file FILENAME, ending at line LINENO.  */
void 
tree_code_create_function_wrapup (unsigned char* filename,
                                 int lineno)
{
  tree block;
  tree fn_decl;

  fn_decl = current_function_decl;
  
  emit_line_note ((const char *)filename, lineno); /* Output the line number information.  */

  /* Get completely built level from debugger symbol table.  */
  
  block = (*lang_hooks.decls.poplevel) (1, 0, 0);
  
  /* Emit rtl for end of scope.  */
  
  expand_end_bindings (block, 0, 1);
  
  /* Emit rtl for end of function.  */
  
  expand_function_end ((const char *)filename, lineno, 0, fn_decl);
  
  /* Pop the level.  */

  block = (*lang_hooks.decls.poplevel) (1, 0, 1);

  /* And attach it to the function.  */
  
  DECL_INITIAL (fn_decl) = block;
  
  /* Emit rtl for end of scope.  */
  
  expand_end_bindings (block, 0, 1);
  
  /* Call optimization and convert optimized rtl to assembly code.  */
  
  rest_of_compilation (fn_decl);
  
  /* We are not inside of any scope now.  */
  
  current_function_decl = NULL_TREE;
}

static void
build_function (tree fndecl, tree stmts, tree block)
{
    DECL_INITIAL(fndecl) = block;
    DECL_SAVED_TREE (fndecl) = stmts ;

    tree resdecl = build_decl(input_location,RESULT_DECL, NULL_TREE, integer_type_node);
    DECL_CONTEXT (resdecl) = fndecl;
    DECL_RESULT(fndecl) = resdecl;
    current_function_decl = fndecl;

    if (DECL_STRUCT_FUNCTION(fndecl) == NULL)
        push_struct_function(fndecl);
    else
		push_cfun(DECL_STRUCT_FUNCTION(fndecl));

    cfun->function_end_locus = BUILTINS_LOCATION;

}

static tree
ubsan_walk_array_refs_r (tree *tp, int *walk_subtrees, void *data)
{
  hash_set<tree> *pset = (hash_set<tree> *) data;

  if (TREE_CODE (*tp) == BIND_EXPR)
    {
      /* Since walk_tree doesn't call the callback function on the decls
	 in BIND_EXPR_VARS, we have to walk them manually, so we can avoid
	 instrumenting DECL_INITIAL of TREE_STATIC vars.  */
      *walk_subtrees = 0;
      for (tree decl = BIND_EXPR_VARS (*tp); decl; decl = DECL_CHAIN (decl))
	{
	  if (TREE_STATIC (decl))
	    continue;
	  walk_tree (&DECL_INITIAL (decl), ubsan_walk_array_refs_r, pset,
		     pset);
	  walk_tree (&DECL_SIZE (decl), ubsan_walk_array_refs_r, pset, pset);
	  walk_tree (&DECL_SIZE_UNIT (decl), ubsan_walk_array_refs_r, pset,
		     pset);
	}
      walk_tree (&BIND_EXPR_BODY (*tp), ubsan_walk_array_refs_r, pset, pset);
    }
  else if (TREE_CODE (*tp) == ADDR_EXPR
	   && TREE_CODE (TREE_OPERAND (*tp, 0)) == ARRAY_REF)
    {
      ubsan_maybe_instrument_array_ref (&TREE_OPERAND (*tp, 0), true);
      /* Make sure ubsan_maybe_instrument_array_ref is not called again
	 on the ARRAY_REF, the above call might not instrument anything
	 as the index might be constant or masked, so ensure it is not
	 walked again and walk its subtrees manually.  */
      tree aref = TREE_OPERAND (*tp, 0);
      pset->add (aref);
      *walk_subtrees = 0;
      walk_tree (&TREE_OPERAND (aref, 0), ubsan_walk_array_refs_r, pset, pset);
      walk_tree (&TREE_OPERAND (aref, 1), ubsan_walk_array_refs_r, pset, pset);
      walk_tree (&TREE_OPERAND (aref, 2), ubsan_walk_array_refs_r, pset, pset);
      walk_tree (&TREE_OPERAND (aref, 3), ubsan_walk_array_refs_r, pset, pset);
    }
  else if (TREE_CODE (*tp) == ARRAY_REF)
    ubsan_maybe_instrument_array_ref (tp, false);
  return NULL_TREE;
}

/* Dump given cgraph node.  */
void
dump_varpool_node (FILE *f, varpool_node *node)
{
  dump_symtab_base (f, node);
  fprintf (f, "  Availability: %s\n",
	   cgraph_function_flags_ready
	   ? cgraph_availability_names[cgraph_variable_initializer_availability (node)]
	   : "not-ready");
  fprintf (f, "  Varpool flags:");
  if (DECL_INITIAL (node->decl))
    fprintf (f, " initialized");
  if (node->output)
    fprintf (f, " output");
  if (TREE_READONLY (node->decl))
    fprintf (f, " read-only");
  if (ctor_for_folding (node->decl) != error_mark_node)
    fprintf (f, " const-value-known");
  fprintf (f, "\n");
}

/* Dump given cgraph node.  */
void
dump_varpool_node (FILE *f, struct varpool_node *node)
{
  dump_symtab_base (f, (symtab_node)node);
  fprintf (f, "  Availability: %s\n",
	   cgraph_function_flags_ready
	   ? cgraph_availability_names[cgraph_variable_initializer_availability (node)]
	   : "not-ready");
  fprintf (f, "  Varpool flags:");
  if (DECL_INITIAL (node->symbol.decl))
    fprintf (f, " initialized");
  if (node->analyzed)
    fprintf (f, " analyzed");
  if (node->finalized)
    fprintf (f, " finalized");
  if (node->output)
    fprintf (f, " output");
  fprintf (f, "\n");
}

void
varpool_analyze_node (struct varpool_node *node)
{
  tree decl = node->symbol.decl;

  /* When reading back varpool at LTO time, we re-construct the queue in order
     to have "needed" list right by inserting all needed nodes into varpool.
     We however don't want to re-analyze already analyzed nodes.  */
  if (!node->analyzed)
    {
      gcc_assert (!in_lto_p || cgraph_function_flags_ready);
      /* Compute the alignment early so function body expanders are
	 already informed about increased alignment.  */
      align_variable (decl, 0);
    }
  if (node->alias && node->alias_of)
    {
      struct varpool_node *tgt = varpool_node_for_decl (node->alias_of);
      struct varpool_node *n;

      for (n = tgt; n && n->alias;
	   n = n->analyzed ? varpool_alias_aliased_node (n) : NULL)
	if (n == node)
	  {
	    error ("variable %q+D part of alias cycle", node->symbol.decl);
	    node->alias = false;
	    continue;
	  }
      if (!vec_safe_length (node->symbol.ref_list.references))
	ipa_record_reference ((symtab_node)node, (symtab_node)tgt, IPA_REF_ALIAS, NULL);
      if (node->extra_name_alias)
	{
	  DECL_WEAK (node->symbol.decl) = DECL_WEAK (node->alias_of);
	  DECL_EXTERNAL (node->symbol.decl) = DECL_EXTERNAL (node->alias_of);
	  DECL_VISIBILITY (node->symbol.decl) = DECL_VISIBILITY (node->alias_of);
	  fixup_same_cpp_alias_visibility ((symtab_node) node,
					   (symtab_node) tgt, node->alias_of);
	}
    }
  else if (DECL_INITIAL (decl))
    record_references_in_initializer (decl, node->analyzed);
  node->analyzed = true;
}

static tree
build_trivial_generic_function ()
{
  auto_vec <tree> param_types;
  tree fndecl = make_fndecl (integer_type_node,
			     "test_fn",
			     param_types);
  ASSERT_TRUE (fndecl != NULL);

  /* Populate the function.  */
  tree retval = build_decl (UNKNOWN_LOCATION, RESULT_DECL,
			    NULL_TREE, integer_type_node);
  DECL_ARTIFICIAL (retval) = 1;
  DECL_IGNORED_P (retval) = 1;
  DECL_RESULT (fndecl) = retval;

  /* Create a BIND_EXPR, and within it, a statement list.  */
  tree stmt_list = alloc_stmt_list ();
  tree_stmt_iterator stmt_iter = tsi_start (stmt_list);
  tree block = make_node (BLOCK);
  tree bind_expr
    = build3 (BIND_EXPR, void_type_node, NULL, stmt_list, block);

  tree modify_retval = build2 (MODIFY_EXPR,
			       integer_type_node,
			       retval,
			       build_int_cst (integer_type_node, 42));
  tree return_stmt = build1 (RETURN_EXPR,
			     integer_type_node,
			     modify_retval);
  tsi_link_after (&stmt_iter, return_stmt, TSI_CONTINUE_LINKING);

  DECL_INITIAL (fndecl) = block;

  /* how to add to function? the following appears to be how to
     set the body of a fndecl: */
  DECL_SAVED_TREE(fndecl) = bind_expr;

  /* Ensure that locals appear in the debuginfo.  */
  BLOCK_VARS (block) = BIND_EXPR_VARS (bind_expr);

  return fndecl;
}

void
compile_resource_data (const char *name, const char *buffer, int length)
{
  tree rtype, field = NULL_TREE, data_type, rinit, data, decl;
  char buf[60];

  data_type = build_prim_array_type (unsigned_byte_type_node,
				     strlen (name) + length);
  rtype = make_node (RECORD_TYPE);
  PUSH_FIELD (rtype, field, "name_length", unsigned_int_type_node);
  PUSH_FIELD (rtype, field, "resource_length", unsigned_int_type_node);
  PUSH_FIELD (rtype, field, "data", data_type);
  FINISH_RECORD (rtype);
  START_RECORD_CONSTRUCTOR (rinit, rtype);
  PUSH_FIELD_VALUE (rinit, "name_length", 
		    build_int_cst (NULL_TREE, strlen (name)));
  PUSH_FIELD_VALUE (rinit, "resource_length", 
		    build_int_cst (NULL_TREE, length));
  data = build_string (strlen(name) + length, buffer);
  TREE_TYPE (data) = data_type;
  PUSH_FIELD_VALUE (rinit, "data", data);
  FINISH_RECORD_CONSTRUCTOR (rinit);
  TREE_CONSTANT (rinit) = 1;
  TREE_INVARIANT (rinit) = 1;

  /* Generate a unique-enough identifier.  */
  sprintf (buf, "_Jr%d", ++Jr_count);

  decl = build_decl (VAR_DECL, get_identifier (buf), rtype);
  TREE_STATIC (decl) = 1;
  DECL_ARTIFICIAL (decl) = 1;
  DECL_IGNORED_P (decl) = 1;
  TREE_READONLY (decl) = 1;
  TREE_THIS_VOLATILE (decl) = 0;
  DECL_INITIAL (decl) = rinit;
  layout_decl (decl, 0);
  pushdecl (decl);
  rest_of_decl_compilation (decl, global_bindings_p (), 0);
  make_decl_rtl (decl);
  assemble_variable (decl, 1, 0, 0);

  resources = tree_cons (NULL_TREE, decl, resources);
}

void
compile_resource_data (const char *name, const char *buffer, int length)
{
  tree rtype, field = NULL_TREE, data_type, rinit, data, decl;
  VEC(constructor_elt,gc) *v = NULL;

  data_type = build_prim_array_type (unsigned_byte_type_node,
				     strlen (name) + length);
  rtype = make_node (RECORD_TYPE);
  PUSH_FIELD (input_location,
	      rtype, field, "name_length", unsigned_int_type_node);
  PUSH_FIELD (input_location,
	      rtype, field, "resource_length", unsigned_int_type_node);
  PUSH_FIELD (input_location, rtype, field, "data", data_type);
  FINISH_RECORD (rtype);
  START_RECORD_CONSTRUCTOR (v, rtype);
  PUSH_FIELD_VALUE (v, "name_length", 
		    build_int_cst (NULL_TREE, strlen (name)));
  PUSH_FIELD_VALUE (v, "resource_length", 
		    build_int_cst (NULL_TREE, length));
  data = build_string (strlen(name) + length, buffer);
  TREE_TYPE (data) = data_type;
  PUSH_FIELD_VALUE (v, "data", data);
  FINISH_RECORD_CONSTRUCTOR (rinit, v, rtype);
  TREE_CONSTANT (rinit) = 1;

  decl = build_decl (input_location,
		     VAR_DECL, java_mangle_resource_name (name), rtype);
  TREE_STATIC (decl) = 1;
  TREE_PUBLIC (decl) = 1;
  java_hide_decl (decl);
  DECL_ARTIFICIAL (decl) = 1;
  DECL_IGNORED_P (decl) = 1;
  TREE_READONLY (decl) = 1;
  TREE_THIS_VOLATILE (decl) = 0;
  DECL_INITIAL (decl) = rinit;
  layout_decl (decl, 0);
  pushdecl (decl);
  rest_of_decl_compilation (decl, global_bindings_p (), 0);
  varpool_finalize_decl (decl);

  VEC_safe_push (tree, gc, resources, decl);
}

static void
build_one_array (gimple swtch, int num, tree arr_index_type, gimple phi,
		 tree tidx)
{
  tree array_type, ctor, decl, value_type, name, fetch;
  gimple load;
  gimple_stmt_iterator gsi;

  gcc_assert (info.default_values[num]);
  value_type = TREE_TYPE (info.default_values[num]);
  array_type = build_array_type (value_type, arr_index_type);

  ctor = build_constructor (array_type, info.constructors[num]);
  TREE_CONSTANT (ctor) = true;

  decl = build_decl (VAR_DECL, NULL_TREE, array_type);
  TREE_STATIC (decl) = 1;
  DECL_INITIAL (decl) = ctor;

  DECL_NAME (decl) = create_tmp_var_name ("CSWTCH");
  DECL_ARTIFICIAL (decl) = 1;
  TREE_CONSTANT (decl) = 1;
  add_referenced_var (decl);
  varpool_mark_needed_node (varpool_node (decl));
  varpool_finalize_decl (decl);
  mark_sym_for_renaming (decl);

  name = make_ssa_name (SSA_NAME_VAR (PHI_RESULT (phi)), NULL);
  info.target_inbound_names[num] = name;

  fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE,
		  NULL_TREE);
  load = gimple_build_assign (name, fetch);
  SSA_NAME_DEF_STMT (name) = load;

  gsi = gsi_for_stmt (swtch);
  gsi_insert_before (&gsi, load, GSI_SAME_STMT);
  mark_symbols_for_renaming (load);

  info.arr_ref_last = load;
}