[cfe-dev] hasAncestor matching nothing

[Manuel Klimek via cfe-dev]

On Fri, Nov 25, 2016 at 9:24 AM Farzad Sadeghi via cfe-dev <
cfe-dev at lists.llvm.org> wrote:

> for the source code below:
> short int test16(int a, int b)
> {
>         short int sum;
>         short unsigned int sumus;
>         sum = a + b;
>         sumus = a + b;
>
>         return sum;
> }
> with AST:
> |-FunctionDecl 0x4e52920 <line:821:1, line:829:1> line:821:11 test16
> 'short (int, int)'
> | |-ParmVarDecl 0x4e527d8 <col:18, col:22> col:22 used a 'int'
> | |-ParmVarDecl 0x4e52848 <col:25, col:29> col:29 used b 'int'
> | `-CompoundStmt 0x4e52d60 <line:822:1, line:829:1>
> |   |-DeclStmt 0x4e52a48 <line:823:2, col:15>
> |   | `-VarDecl 0x4e529e8 <col:2, col:12> col:12 used sum 'short'
> |   |-DeclStmt 0x4e52ad0 <line:824:2, col:26>
> |   | `-VarDecl 0x4e52a70 <col:2, col:21> col:21 used sumus 'unsigned
> short'
> |   |-BinaryOperator 0x4e52bd0 <line:825:2, col:12> 'short' '='
> |   | |-DeclRefExpr 0x4e52ae8 <col:2> 'short' lvalue Var 0x4e529e8 'sum'
> 'short'
> |   | `-ImplicitCastExpr 0x4e52bb8 <col:8, col:12> 'short' <IntegralCast>
> |   |   `-BinaryOperator 0x4e52b90 <col:8, col:12> 'int' '+'
> |   |     |-ImplicitCastExpr 0x4e52b60 <col:8> 'int' <LValueToRValue>
> |   |     | `-DeclRefExpr 0x4e52b10 <col:8> 'int' lvalue ParmVar
> 0x4e527d8 'a' 'int'
> |   |     `-ImplicitCastExpr 0x4e52b78 <col:12> 'int' <LValueToRValue>
> |   |       `-DeclRefExpr 0x4e52b38 <col:12> 'int' lvalue ParmVar
> 0x4e52848 'b' 'int'
> |   |-BinaryOperator 0x4e52ce0 <line:826:2, col:14> 'unsigned short' '='
> |   | |-DeclRefExpr 0x4e52bf8 <col:2> 'unsigned short' lvalue Var
> 0x4e52a70 'sumus' 'unsigned short'
> |   | `-ImplicitCastExpr 0x4e52cc8 <col:10, col:14> 'unsigned short'
> <IntegralCast>
> |   |   `-BinaryOperator 0x4e52ca0 <col:10, col:14> 'int' '+'
> |   |     |-ImplicitCastExpr 0x4e52c70 <col:10> 'int' <LValueToRValue>
> |   |     | `-DeclRefExpr 0x4e52c20 <col:10> 'int' lvalue ParmVar
> 0x4e527d8 'a' 'int'
> |   |     `-ImplicitCastExpr 0x4e52c88 <col:14> 'int' <LValueToRValue>
> |   |       `-DeclRefExpr 0x4e52c48 <col:14> 'int' lvalue ParmVar
> 0x4e52848 'b' 'int'
> |   `-ReturnStmt 0x4e52d48 <line:828:2, col:9>
> |     `-ImplicitCastExpr 0x4e52d30 <col:9> 'short' <LValueToRValue>
> |       `-DeclRefExpr 0x4e52d08 <col:9> 'short' lvalue Var 0x4e529e8
> 'sum' 'short'
> when i run the below matcher on clang-query:
> match declRefExpr(hasAncestor(declRefExpr()))
> i get no matches, while in the AST it clearly says that there are such

nodes. so I was wondering what could be causing this.
>

Perhaps we can make the printing easier to read here:
-a
||-b
|`-c
does not mean that c is a child of b, it means (if I'm not mistaken) that c
is the last child of a, but both b and a are equally children of a.


> --
> Farzad Sadeghi
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
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