C 旧bison/flex代码无法编译_C_Compiler Errors_Bison

C 旧bison/flex代码无法编译

c compiler-errors bison

C 旧bison/flex代码无法编译,c,compiler-errors,bison,C,Compiler Errors,Bison,我继承了一些非常古老的bison代码，我已经有一段时间没有处理这些代码了，编译失败了，出现了许多警告和错误，我可以解决这些警告，但我不知道如何纠正这些错误。下面是一个例子：鉴于这组定义： %% pgm: exp { pgm = $1; } exp: list { $$ = dlink(newnode(NULL,NULL),$1); } | exp ';' li

我继承了一些非常古老的bison代码，我已经有一段时间没有处理这些代码了，编译失败了，出现了许多警告和错误，我可以解决这些警告，但我不知道如何纠正这些错误。下面是一个例子：

鉴于这组定义：

    %%
    pgm:    exp                     { pgm = $1; }

    exp:    list                    { $$ = dlink(newnode(NULL,NULL),$1); }
    |       exp ';' list            { $$ = Link($1, dlink(newnode(NULL,NULL),$3)); }

    list:   rec
    |       list ',' rec            { $$ = Link($1, $3); }

    rec:    /* null */              { $$ = newnode(NULL, NULL); }
    |       path
    |       path '@' NAME           { $$ = attribute($1, $3); }
    |       path '(' list ')'       { $$ = dlink($1, $3); }

    path:   NAME                    { $$ = newnode($1, NULL); }
    |       path '.' NAME           { $$ = dlink($1, newnode($3, NULL)); }
    |       path '[' INT ']'        { $$ = dlink($1, newnode($3, $3)); }
    |       path '[' INT '-' INT ']'{ $$ = dlink($1, newnode($3, $5)); }

    %%

这些资料汇编如下：

    bison -d -y gram.y
    gcc -std=c89 -c y.tab.c

我发现以下错误（这只是众多错误之一）：

我将回答这个问题，因为它涉及的主题可能会使学习使用bison/yacc的学生和那些正在编译旧代码并对错误来源感到困惑的人（如OP）感到困惑

正如评论中暗示的，这些错误与bison完全无关，而是来自bison文件中包含的C代码，但不是bison的人工制品，也不是由bison或yacc多年来的变化引起的。它们是由多年来C编译器的变化引起的。现代的C编译器比以前的非常旧的编译器宽容（更好），特别是在函数调用和参数检查方面。即使在现代编译器上选择选项以实现向后兼容性时，当以前的编译器可能什么也没说或只是发出警告时，有时仍会产生错误

要证明故障完全在C中，可以执行以下操作：

Prompt> gcc -c -xc -std=c89 -
main () {
#line 49 "gram.y"
int a  = newnode(a,1);
int * b  = newnode(1,1);
}
void *
#line 218 "gram.y"
newnode(name, range)
int name,
range;
{
}
^Z
gram.y: In function 'main':
gram.y:50:12: warning: initialization makes pointer from integer without a cast
[enabled by default]

            ^
gram.y: At top level:
gram.y:218:1: error: conflicting types for 'newnode'
gram.y:49:10: note: previous implicit declaration of 'newnode' was here

          ^

您可以看到，在C的几行代码中，gcc将输出与您看到的相同的错误消息

关于这个问题，以及如何解决这个问题，人们有很多看法：

脚注：可以通过使用或控制错误诊断的级别来关闭某些gcc错误，或将其减少为警告，但在这种情况下是不可能的。这个该行：

#pragma GCC diagnostic warning "-Werror-implicit-function-declaration"

（或类似）也不能消除错误。只是提一下，以防有人想知道

野牛的类型冲突许多人在bison/yacc中使用类似代码时，确实存在bison检测到的代码类型不匹配问题。为了使答案更加完整，可能需要在这方面添加一些注释。通常情况下，在解析类似于语法的内容时，使用函数
dlink
、
Link
、
newnode
和
属性创建解析树。树将由一些struct 组成，并通过指向structstruct* 的指针链接，如下所示： struct treeNode { int item1,item2; struct treeNode *left; struct treeNode *right; }; typedef struct treeNode TREE_NODE; typedef TREE_NODE *BINARY_TREE; BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); BINARY_TREE newnode(int item1, int item2); BINARY_TREE attribute(BINARY_TREE left, int item); BINARY_TREE Link(BINARY_TREE left, BINARY_TREE right); 为了避免前面所示的隐式函数类型的问题，我们可以像下面这样声明函数的原型： struct treeNode { int item1,item2; struct treeNode *left; struct treeNode *right; }; typedef struct treeNode TREE_NODE; typedef TREE_NODE *BINARY_TREE; BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); BINARY_TREE newnode(int item1, int item2); BINARY_TREE attribute(BINARY_TREE left, int item); BINARY_TREE Link(BINARY_TREE left, BINARY_TREE right); 我们可以将其与您的语法结合起来生成此文件： %{ #define NULL 0 struct treeNode { int item1,item2; struct treeNode *left; struct treeNode *right; }; typedef struct treeNode TREE_NODE; typedef TREE_NODE *BINARY_TREE; BINARY_TREE pgm; BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); BINARY_TREE newnode(int item1, int item2); BINARY_TREE attribute(BINARY_TREE left, int item); BINARY_TREE Link(BINARY_TREE left, BINARY_TREE right); %} %token INT NAME %% pgm: exp { pgm = $1; } exp: list { $$ = dlink(newnode(NULL,NULL),$1); } | exp ';' list { $$ = Link($1, dlink(newnode(NULL,NULL),$3)); } list: rec | list ',' rec { $$ = Link($1, $3); } rec: /* null */ { $$ = newnode(NULL, NULL); } | path | path '@' NAME { $$ = attribute($1, $3); } | path '(' list ')' { $$ = dlink($1, $3); } path: NAME { $$ = newnode($1, NULL); } | path '.' NAME { $$ = dlink($1, newnode($3, NULL)); } | path '[' INT ']' { $$ = dlink($1, newnode($3, $3)); } | path '[' INT '-' INT ']'{ $$ = dlink($1, newnode($3, $5)); } %% 也许你有的是这样的？如果我们把它通过bison和gcc，我们会得到很多警告，但它会生成代码。我注意到你说你有很多警告。也许他们是这样的： gram.y: In function 'yyparse': gram.y:23:11: warning: assignment makes pointer from integer without a cast [enabled by default] pgm: exp { pgm = $1; } ^ gram.y:25:5: warning: passing argument 2 of 'dlink' makes pointer from integer without a cast [enabled by default] exp: list { $$ = dlink(newnode(NULL,NULL),$1); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); ^ gram.y:25:18: warning: assignment makes integer from pointer without a cast [enabled by default] exp: list { $$ = dlink(newnode(NULL,NULL),$1); } ^ gram.y:26:5: warning: passing argument 2 of 'dlink' makes pointer from integer without a cast [enabled by default] | exp ';' list { $$ = Link($1, dlink(newnode(NULL,NULL),$3)); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); gram.y:25:18: warning: assignment makes integer from pointer without a cast [enabled by default] exp: list { $$ = dlink(newnode(NULL,NULL),$1); } ^ gram.y:26:5: warning: passing argument 2 of 'dlink' makes pointer from integer without a cast [enabled by default] | exp ';' list { $$ = Link($1, dlink(newnode(NULL,NULL),$3 )); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); ^ gram.y:26:5: warning: passing argument 1 of 'Link' makes pointer from integer without a cast [enabled by default] | exp ';' list { $$ = Link($1, dlink(newnode(NULL,NULL),$3 )); } ^ gram.y:17:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE Link(BINARY_TREE left, BINARY_TREE right); ^ gram.y:26:15: warning: assignment makes integer from pointer without a cast [enabled by default] | exp ';' list { $$ = Link($1, dlink(newnode(NULL,NULL),$3 )); } ^ gram.y:29:5: warning: passing argument 1 of 'Link' makes pointer from integer without a cast [enabled by default] | list ',' rec { $$ = Link($1, $3); } ^ gram.y:17:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE Link(BINARY_TREE left, BINARY_TREE right); ^ gram.y:29:5: warning: passing argument 2 of 'Link' makes pointer from integer without a cast [enabled by default] | list ',' rec { $$ = Link($1, $3); } ^ gram.y:17:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE Link(BINARY_TREE left, BINARY_TREE right); ^ gram.y:29:15: warning: assignment makes integer from pointer without a cast [enabled by default] | list ',' rec { $$ = Link($1, $3); } ^ gram.y:31:15: warning: assignment makes integer from pointer without a cast [enabled by default] rec: /* null */ { $$ = newnode(NULL, NULL); } ^ gram.y:33:5: warning: passing argument 1 of 'attribute' makes pointer from integer without a cast [enabled by default] | path '@' NAME { $$ = attribute($1, $3); } ^ gram.y:16:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE attribute(BINARY_TREE left, int item); ^ gram.y:33:15: warning: assignment makes integer from pointer without a cast [enabled by default] | path '@' NAME { $$ = attribute($1, $3); } ^ gram.y:34:5: warning: passing argument 1 of 'dlink' makes pointer from integer without a cast [enabled by default] | path '(' list ')' { $$ = dlink($1, $3); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); ^ gram.y:34:5: warning: passing argument 2 of 'dlink' makes pointer from integer without a cast [enabled by default] | path '(' list ')' { $$ = dlink($1, $3); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); ^ gram.y:34:15: warning: assignment makes integer from pointer without a cast [enabled by default] | path '(' list ')' { $$ = dlink($1, $3); } ^ gram.y:36:15: warning: assignment makes integer from pointer without a cast [enabled by default] path: NAME { $$ = newnode($1, NULL); } ^ gram.y:37:5: warning: passing argument 1 of 'dlink' makes pointer from integer without a cast [enabled by default] | path '.' NAME { $$ = dlink($1, newnode($3, NULL)); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); ^ gram.y:37:15: warning: assignment makes integer from pointer without a cast [enabled by default] | path '.' NAME { $$ = dlink($1, newnode($3, NULL)); } ^ gram.y:38:5: warning: passing argument 1 of 'dlink' makes pointer from integer without a cast [enabled by default] | path '[' INT ']' { $$ = dlink($1, newnode($3, $3)); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); ^ gram.y:38:15: warning: assignment makes integer from pointer without a cast [enabled by default] | path '[' INT ']' { $$ = dlink($1, newnode($3, $3)); } ^ gram.y:39:5: warning: passing argument 1 of 'dlink' makes pointer from integer without a cast [enabled by default] | path '[' INT '-' INT ']'{ $$ = dlink($1, newnode($3, $5)); } ^ gram.y:14:13: note: expected 'BINARY_TREE' but argument is of type 'YYSTYPE' BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); ^ gram.y:39:15: warning: assignment makes integer from pointer without a cast [enabled by default] | path '[' INT '-' INT ']'{ $$ = dlink($1, newnode($3, $5)); } ^ 对于野牛的新用户来说，这可能非常常见。为了消除这些警告，有必要通知bison如何使用这些类型来生成类型正确的代码。这是通过在bison代码中添加两行代码来完成的。首先，我们必须告诉它语法规则操作可以返回的类型： %union { BINARY_TREE tVal; int iVal; } %token <iVal> NAME INT %type <tVal> exp list rec path 然后我们必须告诉它为单个令牌和规则操作返回的类型： %union { BINARY_TREE tVal; int iVal; } %token <iVal> NAME INT %type <tVal> exp list rec path %token NAME INT %类型exp list rec path 如果我们将其插入语法文件中，所有错误和警告都将被消除，我们得到： %{ #define NULL 0 struct treeNode { int item1,item2; struct treeNode *left; struct treeNode *right; }; typedef struct treeNode TREE_NODE; typedef TREE_NODE *BINARY_TREE; BINARY_TREE pgm; BINARY_TREE dlink(BINARY_TREE left, BINARY_TREE right); BINARY_TREE newnode(int item1, int item2); BINARY_TREE attribute(BINARY_TREE left, int item); BINARY_TREE Link(BINARY_TREE left, BINARY_TREE right); %} %union { BINARY_TREE tVal; int iVal; } %token <iVal> NAME INT %type <tVal> exp list rec path %% pgm: exp { pgm = $1; } exp: list { $$ = dlink(newnode(NULL,NULL),$1); } | exp ';' list { $$ = Link($1, dlink(newnode(NULL,NULL),$3)); } list: rec | list ',' rec { $$ = Link($1, $3); } rec: /* null */ { $$ = newnode(NULL, NULL); } | path | path '@' NAME { $$ = attribute($1, $3); } | path '(' list ')' { $$ = dlink($1, $3); } path: NAME { $$ = newnode($1, NULL); } | path '.' NAME { $$ = dlink($1, newnode($3, NULL)); } | path '[' INT ']' { $$ = dlink($1, newnode($3, $3)); } | path '[' INT '-' INT ']'{ $$ = dlink($1, newnode($3, $5)); } %% %{ #定义空0 树状结构{ int第1项、第2项；结构树节点*左；结构树节点*右侧； }; 类型定义结构树节点树节点； typedef树节点*二叉树；二叉树pgm；二叉树链接（左二叉树，右二叉树）；二叉树newnode（int item1，int item2）；二叉树属性（左二叉树，int项）；二叉树链接（左二叉树，右二叉树）； %} %联合{ 二叉树tVal；国际竞争力； } %令牌名称INT %类型exp list rec path %% pgm:exp{pgm=$1；} exp:list{$$=dlink（newnode（NULL，NULL），$1）；} |exp'；'列表{$$=Link（$1，dlink（newnode（NULL，NULL），$3））；} 名单：rec |列表“，”rec{$$=Link（$1，$3）；} rec://*null*/{$$=newnode（null，null）；} |路径 |路径“@”名称{$$=属性（$1，$3）；} |路径“（'list'）”{$$=dlink（$1，$3）；} 路径：名称{$$=newnode（$1，NULL）；} |路径“.”名称{$$=dlink（$1，newnode（$3，NULL））；} |路径“['INT']”{$$=dlink（$1，newnode（$3，$3））；} |路径“['INT'-'INT']”{$$=dlink（$1，newnode（$3，$5））；} %% 我希望我在C代码中发现了一些类型冲突的方面，这些方面可能会影响bison的新用户或采用其他代码库的用户。显示gram.y声明newnode的部分。它在哪里，在规则之前还是之后？“newnode的先前隐式声明在这里”。看到了吗？这意味着，newnode 从未明确声明过，也就是说，y.lex.c 或其包含的任何标题中没有它的原型。在这样小的背景下回答是不可能的，例如，NAME 的语义类型是什么？对答案的元评论：我确实将原始问题标记为无法回答，因为我们无法重现该问题。这意味着社区认为它应该得到一个答案，所以我做了一个。这并不是说社区认为它应该得到一个答案，而是社区没有足够快地审查国旗（或者版主没有足够快地处理队列）。