Clang ast-dump不显示一些全局变量

Question

我有一个CPP文件，我正在使用clang打印全局范围内的所有变量。问题是：命令clang -cc1 -ast-dump filename.cpp不显示一些全局变量：

| -VarDecl 0x2094370 N '诠释' 无效

| -VarDecl 0x20943e0 MAXN 'const int的' 无效

| - VarDecl 0x2094470 p '诠释' 无效

| -VarDecl 0x20944e0 U '_Bool' 无效

| -VarDecl 0x2094550 ansv '诠释' 无效

| -VarDecl 0x20945c0成本 '诠释' 无效

我的CPP文件有以下全局变量：

size_t N,M; 
const size_t MAXN = 40000; 
std::vector<std::pair<size_t,size_t> > graph[MAXN],query[MAXN],qr; 
size_t p[MAXN], ancestor[MAXN]; 
bool u[MAXN]; 
size_t ansv[MAXN]; 
size_t cost[MAXN]; 

可以看到，AST-转储没有打印一些全局变量（用于例如，所有std::vector变量都被错过了）。我究竟做错了什么？

UPD：全CPP文件：

#include<iostream> 
#include<vector> 
#include<algorithm> 

size_t N,M; 
const size_t MAXN = 40000; 
std::vector<std::pair<size_t,size_t> > graph[MAXN],query[MAXN],qr; 
size_t p[MAXN], ancestor[MAXN]; 
bool u[MAXN]; 
size_t ansv[MAXN]; 
size_t cost[MAXN]; 

size_t find_set(size_t x){ 
    //not important for my problem 
} 

void unite(size_t a, size_t b, size_t new_ancestor){ 
    //not important for my problem 
} 

void dfs(size_t v,size_t ct){ 
    //not important for my problem 
} 

int main(int argc, char* argv[]){ 
    //not important for my problem 
} 

Answer 1

您正在使用clang++ -cc1 -ast-dump，它假设输入是预处理的。当我这样做，我得到的错误，因为它无法找到std::vector，std::pair，size_t，这就是为什么在这样一个行说无效：

|-VarDecl 0x3149810 <testing.cpp:19:1, col:8> col:8 invalid N 'int' 
|-VarDecl 0x3149880 <line:20:1, col:14> col:14 invalid MAXN 'const int' 

注意在这些线路的“无效” - 这意味着它是“不是有效的声明”。

在这种情况下，部分编译器错误恢复是“假定每个声明中只有一个变量，并跳到下一个分号”。

我修改你的代码是这样的：

namespace std 
{ 
    template <typename T> 
    class vector 
    { 
    }; 

    template <typename T1, typename T2> 
    class pair 
    { 
    }; 
}; 

typedef int size_t; 

size_t N,M; 
const size_t MAXN = 40000; 
std::vector<std::pair<size_t,size_t> > graph[MAXN],query[MAXN],qr; 
size_t p[MAXN], ancestor[MAXN]; 
bool u[MAXN]; 
size_t ansv[MAXN]; 
size_t cost[MAXN]; 

size_t find_set(size_t x){ 
    //not important for my problem 
    return 0; 
} 

void unite(size_t a, size_t b, size_t new_ancestor){ 
    //not important for my problem 
} 

void dfs(size_t v,size_t ct){ 
    //not important for my problem 
} 

int main(int argc, char* argv[]){ 
    //not important for my problem 
} 

在这一点上，我得到：

TranslationUnitDecl 0x4916de0 <<invalid sloc>> <invalid sloc> 
|-TypedefDecl 0x4917320 <<invalid sloc>> <invalid sloc> implicit __int128_t '__int128' 
|-TypedefDecl 0x4917380 <<invalid sloc>> <invalid sloc> implicit __uint128_t 'unsigned __int128' 
|-TypedefDecl 0x4917780 <<invalid sloc>> <invalid sloc> implicit __builtin_va_list '__va_list_tag [1]' 
|-NamespaceDecl 0x49177d0 <testing.cpp:1:1, line:12:1> line:1:11 std 
| |-ClassTemplateDecl 0x4917970 <line:3:5, line:6:5> line:4:11 vector 
| | |-TemplateTypeParmDecl 0x4917830 <line:3:15, col:24> col:24 typename T 
| | |-CXXRecordDecl 0x49178e0 <line:4:5, line:6:5> line:4:11 class vector definition 
| | | `-CXXRecordDecl 0x49588f0 <col:5, col:11> col:11 implicit class vector 
| | `-ClassTemplateSpecializationDecl 0x49593b0 <line:3:5, line:6:5> line:4:11 class vector definition 
| | |-TemplateArgument type 'class std::pair<int, int>' 
| | |-CXXRecordDecl 0x4959750 prev 0x49593b0 <col:5, col:11> col:11 implicit class vector 
| | |-CXXConstructorDecl 0x495ff30 <col:11> col:11 implicit used vector 'void (void) throw()' inline 
| | | `-CompoundStmt 0x4960260 <col:11> 
| | `-CXXConstructorDecl 0x4960090 <col:11> col:11 implicit vector 'void (const class std::vector<class std::pair<int, int> > &)' inline noexcept-unevaluated 0x4960090 
| |  `-ParmVarDecl 0x49601d0 <col:11> col:11 'const class std::vector<class std::pair<int, int> > &' 
| `-ClassTemplateDecl 0x4958b40 <line:8:5, line:11:5> line:9:11 pair 
| |-TemplateTypeParmDecl 0x4958980 <line:8:15, col:24> col:24 typename T1 
| |-TemplateTypeParmDecl 0x49589f0 <col:28, col:37> col:37 typename T2 
| |-CXXRecordDecl 0x4958ab0 <line:9:5, line:11:5> line:9:11 class pair definition 
| | `-CXXRecordDecl 0x4958de0 <col:5, col:11> col:11 implicit class pair 
| `-ClassTemplateSpecializationDecl 0x4959140 <line:8:5, line:11:5> line:9:11 class pair 
|  |-TemplateArgument type 'int' 
|  `-TemplateArgument type 'int' 
|-EmptyDecl 0x4958e70 <line:12:2> col:2 
|-TypedefDecl 0x4958ea0 <line:14:1, col:13> col:13 referenced size_t 'int' 
|-VarDecl 0x4958f20 <line:17:1, col:8> col:8 N 'size_t':'int' 
|-VarDecl 0x4958f90 <col:1, col:10> col:10 M 'size_t':'int' 
|-VarDecl 0x4959010 <line:18:1, col:21> col:14 referenced MAXN 'const size_t':'const int' cinit 
| `-IntegerLiteral 0x4959068 <col:21> 'int' 40000 
|-VarDecl 0x4959690 <line:19:1, col:50> col:40 graph 'std::vector<std::pair<size_t, size_t> > [40000]' callinit 
| `-CXXConstructExpr 0x4960278 <col:40> 'std::vector<std::pair<size_t, size_t> > [40000]' 'void (void) throw()' 
|-VarDecl 0x49603f0 <col:1, col:62> col:52 query 'std::vector<std::pair<size_t, size_t> > [40000]' callinit 
| `-CXXConstructExpr 0x4960448 <col:52> 'std::vector<std::pair<size_t, size_t> > [40000]' 'void (void) throw()' 
|-VarDecl 0x49604c0 <col:1, col:64> col:64 qr 'std::vector<std::pair<size_t, size_t> >':'class std::vector<class std::pair<int, int> >' callinit 
| `-CXXConstructExpr 0x4960518 <col:64> 'std::vector<std::pair<size_t, size_t> >':'class std::vector<class std::pair<int, int> >' 'void (void) throw()' 
|-VarDecl 0x4960650 <line:20:1, col:14> col:8 p 'size_t [40000]' 
|-VarDecl 0x4960710 <col:1, col:30> col:17 ancestor 'size_t [40000]' 
|-VarDecl 0x4960820 <line:21:1, col:12> col:6 u '_Bool [40000]' 
|-VarDecl 0x49608e0 <line:22:1, col:17> col:8 ansv 'size_t [40000]' 
|-VarDecl 0x49609a0 <line:23:1, col:17> col:8 cost 'size_t [40000]' 
|-FunctionDecl 0x4960b10 <line:25:1, line:28:1> line:25:8 find_set 'size_t (size_t)' 
| |-ParmVarDecl 0x4960a10 <col:17, col:24> col:24 x 'size_t':'int' 
| `-CompoundStmt 0x4960bf8 <col:26, line:28:1> 
| `-ReturnStmt 0x4960bd8 <line:27:5, col:12> 
|  `-IntegerLiteral 0x4960bb8 <col:12> 'int' 0 
|-FunctionDecl 0x4960e40 <line:30:1, line:32:1> line:30:6 unite 'void (size_t, size_t, size_t)' 
| |-ParmVarDecl 0x4960c30 <col:12, col:19> col:19 a 'size_t':'int' 
| |-ParmVarDecl 0x4960ca0 <col:22, col:29> col:29 b 'size_t':'int' 
| |-ParmVarDecl 0x4960d10 <col:32, col:39> col:39 new_ancestor 'size_t':'int' 
| `-CompoundStmt 0x4960ef8 <col:52, line:32:1> 
|-FunctionDecl 0x49618d0 <line:34:1, line:36:1> line:34:6 dfs 'void (size_t, size_t)' 
| |-ParmVarDecl 0x4961750 <col:10, col:17> col:17 v 'size_t':'int' 
| |-ParmVarDecl 0x49617c0 <col:19, col:26> col:26 ct 'size_t':'int' 
| `-CompoundStmt 0x4961980 <col:29, line:36:1> 
`-FunctionDecl 0x4961c00 <line:38:1, line:40:1> line:38:5 main 'int (int, char **)' 
    |-ParmVarDecl 0x49619b0 <col:10, col:14> col:14 argc 'int' 
    |-ParmVarDecl 0x4961af0 <col:20, col:31> col:26 argv 'char **':'char **' 
    `-CompoundStmt 0x4961cb0 <col:33, line:40:1> 

正确的解决方法当然是不使用-cc1，只是使用原始文件与-c -Xclang -ast-dump，但这会产生相当大量的文本（向量，对，iostream等的所有成员函数）。所以如果你对某个特定部分感兴趣，也许可以从头文件中删除所需的部分，并只处理实际需要的部分 - 当然，这一切取决于你实际尝试实现的内容。

Answer 2

看来，铛想不通类型的所有声明符在声明size_t N,M创造VarDecl为他们所有，但第一。关注这些声明后的“无效”。

随着完整的例子，有

|-VarDecl 0x102bf5d60 <blah.cpp:4:1, col:8> N 'size_t':'unsigned long' 
|-VarDecl 0x102bf5dd0 <col:1, col:10> M 'size_t':'unsigned long' 

等他们全部。

一旦我删除包括定义size_t和std::vector，铛开始抱怨未定义的类型，并且不产生VarDecl，因为它没有之前创建Type。