gcc源代码分析，grokdeclarator()函数分析

grokdeclarator ()函数有2次被调用的情况。

第一种情况在函数push_parm_decl ()函数中。

/* Given a parsed parameter declaration,
   decode it into a PARM_DECL and push that on the current binding level.  */

void
push_parm_decl (parm)
     tree parm;
{
  register tree decl = grokdeclarator (TREE_VALUE (parm), TREE_PURPOSE (parm),
                       PARM, 0);

  /* Add this decl to the current binding level.  */
  finish_decl (pushdecl (decl), NULL_TREE, NULL_TREE);
}

grokdeclarator ()函数中的部分代码：

    if (initialized)
      error ("parameter `%s' is initialized", name);

    decl = build_decl (PARM_DECL, declarator, type);

调试结果：

build_decl

 <pointer_type 9117c
    type <integer_type 91130 char readonly permanent QI
        size <integer_cst 82638 literal permanent 1
        align 8 size_unit 8 sep_unit 8 symtab 0
        sep <integer_cst 82608 literal permanent -128 precision 8 min <integer_cst 82608 -128>
        max <integer_cst 82620 literal permanent 127
        pointer_to_this <pointer_type 9117c>
    permanent unsigned SI
    size <integer_cst 8254c type <integer_type 82848* unsigned int> literal permanent 4
    align 32 size_unit 8 sep_unit 32 symtab 0
    chain <function_type 912c0>
 <parm_decl 941c0
    type <pointer_type 9117c
        type <integer_type 91130 char readonly permanent QI
            size <integer_cst 82638 literal permanent 1
            align 8 size_unit 8 sep_unit 8 symtab 0
            sep <integer_cst 82608 literal permanent -128 precision 8 min <integer_cst 82608 -128>
            max <integer_cst 82620 literal permanent 127
            pointer_to_this <pointer_type 9117c>
        permanent unsigned SI
        size <integer_cst 8254c literal permanent 4
        align 32 size_unit 8 sep_unit 32 symtab 0
        chain <function_type 912c0>
    unsigned SI file /usr/include/stdio.h line 214 size <integer_cst 8254c 4>
    align 32 size_unit 8 offset 0
 <parm_decl 941c0
    type <pointer_type 9117c
        type <integer_type 91130 char readonly permanent QI
            size <integer_cst 82638 literal permanent 1
            align 8 size_unit 8 sep_unit 8 symtab 0
            sep <integer_cst 82608 literal permanent -128 precision 8 min <integer_cst 82608 -128>
            max <integer_cst 82620 literal permanent 127
            pointer_to_this <pointer_type 9117c>
        permanent unsigned SI
        size <integer_cst 8254c literal permanent 4
        align 32 size_unit 8 sep_unit 32 symtab 0
        chain <function_type 912c0>
    unsigned SI file /usr/include/stdio.h line 214 size <integer_cst 8254c 4>

    align 32 size_unit 8 offset 0 arguments <pointer_type 9117c>

第二种情况在函数start_decl ()函数中。

tree
start_decl (declarator, declspecs, initialized)
     tree declspecs, declarator;
     int initialized;
{
  register tree decl = grokdeclarator (declarator, declspecs,
                       NORMAL, initialized);

参数调试结果：

 <call_expr 956c8 permanent
    arg 0 <identifier_node 95540 printf permanent
    arg 1 <tree_list 956b0 permanent
        purpose <parm_decl 941c0 type <pointer_type 9117c>
            unsigned SI file /usr/include/stdio.h line 214
            size <integer_cst 8254c literal permanent 4
            align 32 size_unit 8 offset 0 arguments <pointer_type 9117c>
        chain <tree_list 95698 permanent value <pointer_type 9117c> chain <tree_list 95698>(nil)

 <tree_list 95608 permanent
    value <identifier_node 82008 int permanent
        global <type_decl 82564 int type <integer_type 824d0* int>
            permanent VOID file (null) line 0

            align 1 size_unit 1 offset 0

grokdeclarator ()函数返回结果：

 <function_decl 95740 printf
    type <function_type 956e8
        type <integer_type 824d0 int permanent SI
            size <integer_cst 8254c literal permanent 4
            align 32 size_unit 8 sep_unit 32 symtab 0
            sep <integer_cst 8251c literal permanent -2147483648 precision 32 min <integer_cst 8251c -2147483648>
            max <integer_cst 82534 literal permanent 2147483647
            pointer_to_this <pointer_type 88b4c> chain <integer_type 825bc* char>
        permanent EP
        size <integer_cst 82dd8 literal permanent 8
        align 32 size_unit 8 sep_unit 0 symtab 0
        arg-types <tree_list 95698 permanent value <pointer_type 9117c>
    external public permanent QI file /usr/include/stdio.h line 214
    align 1 size_unit 1 offset 0

...

      arg_types = grokparms (TREE_OPERAND (declarator, 1),
                 funcdef_flag
                 /* Say it's a definition
                    only for the CALL_EXPR
                    closest to the identifier.  */
                 && TREE_CODE (TREE_OPERAND (declarator, 0)) == IDENTIFIER_NODE);
#if 0 /* This seems to be false.  We turn off temporary allocation
     above in this function if -traditional.
     And this code caused inconsistent results with prototypes:
     callers would ignore them, and pass arguments wrong.  */

      /* Omit the arg types if -traditional, since the arg types
         and the list links might not be permanent.  */
      type = build_function_type (type, flag_traditional ? 0 : arg_types);
#endif
      type = build_function_type (type, arg_types);
      declarator = TREE_OPERAND (declarator, 0);

arg_types = grokparms (之后为

 <tree_list 95698 permanent
    value <pointer_type 9117c
        type <integer_type 91130 char readonly permanent QI
            size <integer_cst 82638 literal permanent 1
            align 8 size_unit 8 sep_unit 8 symtab 0
            sep <integer_cst 82608 literal permanent -128 precision 8 min <integer_cst 82608 -128>
            max <integer_cst 82620 literal permanent 127
            pointer_to_this <pointer_type 9117c>
        permanent unsigned SI
        size <integer_cst 8254c literal permanent 4
        align 32 size_unit 8 sep_unit 32 symtab 0
        chain <function_type 912c0>

      type = build_function_type ( 之前type为：
 <integer_type 824d0 int permanent SI
    size <integer_cst 8254c type <integer_type 82848* unsigned int> literal permanent 4
    align 32 size_unit 8 sep_unit 32 symtab 0
    sep <integer_cst 8251c type <integer_type 824d0* int> literal permanent -2147483648 precision 32 min <integer_cst 8251c -2147483648>
    max <integer_cst 82534 type <integer_type 824d0* int> literal permanent 2147483647
    pointer_to_this <pointer_type 88b4c> chain <integer_type 825bc* char>

type = build_function_type ( 之后type为：

 <function_type 956e8
    type <integer_type 824d0 int permanent SI
        size <integer_cst 8254c literal permanent 4
        align 32 size_unit 8 sep_unit 32 symtab 0
        sep <integer_cst 8251c literal permanent -2147483648 precision 32 min <integer_cst 8251c -2147483648>
        max <integer_cst 82534 literal permanent 2147483647
        pointer_to_this <pointer_type 88b4c> chain <integer_type 825bc* char>
    permanent EP
    size <integer_cst 82dd8 type <integer_type 82848* unsigned int> literal permanent 8
    align 32 size_unit 8 sep_unit 0 symtab 0
    arg-types <tree_list 95698 permanent
        value <pointer_type 9117c type <integer_type 91130* char>
            permanent unsigned SI size <integer_cst 8254c 4>
            align 32 size_unit 8 sep_unit 32 symtab 0
            chain <function_type 912c0>

这次调用build_decl ()函数。

    else if (TREE_CODE (type) == FUNCTION_TYPE)
      {
...

调用build_decl函数之前 declarator为

 <identifier_node 95540 printf permanent

调用build_decl函数之前type 为

 <function_type 956e8
    type <integer_type 824d0 int permanent SI
        size <integer_cst 8254c literal permanent 4
        align 32 size_unit 8 sep_unit 32 symtab 0
        sep <integer_cst 8251c literal permanent -2147483648 precision 32 min <integer_cst 8251c -2147483648>
        max <integer_cst 82534 literal permanent 2147483647
        pointer_to_this <pointer_type 88b4c> chain <integer_type 825bc* char>
    permanent EP
    size <integer_cst 82dd8 type <integer_type 82848* unsigned int> literal permanent 8
    align 32 size_unit 8 sep_unit 0 symtab 0
    arg-types <tree_list 95698 permanent
        value <pointer_type 9117c type <integer_type 91130* char>
            permanent unsigned SI size <integer_cst 8254c 4>
            align 32 size_unit 8 sep_unit 32 symtab 0
            chain <function_type 912c0>

    decl = build_decl (FUNCTION_DECL, declarator, type);

调用build_decl函数之后

 <function_decl 95740 printf
    type <function_type 956e8
        type <integer_type 824d0 int permanent SI
            size <integer_cst 8254c literal permanent 4
            align 32 size_unit 8 sep_unit 32 symtab 0
            sep <integer_cst 8251c literal permanent -2147483648 precision 32 min <integer_cst 8251c -2147483648>
            max <integer_cst 82534 literal permanent 2147483647
            pointer_to_this <pointer_type 88b4c> chain <integer_type 825bc* char>
        permanent EP
        size <integer_cst 82dd8 literal permanent 8
        align 32 size_unit 8 sep_unit 0 symtab 0
        arg-types <tree_list 95698 permanent value <pointer_type 9117c>
    permanent QI file /usr/include/stdio.h line 214
    align 1 size_unit 1 offset 0