astprinter

astprinter is a small commandline-based tool developed to explore the Clang abstract syntax tree (AST). The main goal is to make it easier to get specific AST nodes by specifying line numbers of the C/C++ source code. In conjunction with tools like clang-query, AST matchers can be written and tested more quickly.

Main features

Explore the AST nodes of a translation unit

• Use the line(s) of the C/C++ source code to get the corresponding AST nodes
• Match function names (with regex) to print the AST nodes of the declaration/definition

Usage

See main.cpp for all possible commandline arguments.

Example of using astprinter

Assume test.c contains the code:

int foo () {
    return 2; 
}
int main() {
    int val;
    val = foo();    
    return 0;
}

Using astprinter on test.c

In this example we

1. load test.c with standard Clang flags,
2. list all function declarations in test.c,
3. print the AST definition of foo, and finally,
4. print the AST of the return statement in line 2.

ahueck@sys:~/astprint/install$ ./bin/astprinter ../test.c --
ast-printer> l
foo:~/astprint/install/../test.c:1:3->3:4
main:~/astprint/install/../test.c:4:3->8:4

ast-printer> p foo
FunctionDecl 0x3977120 <test.c:1:3, line:3:3> line:1:7 used foo 'int ()'
`-CompoundStmt 0x3977238 <col:14, line:3:3>
  `-ReturnStmt 0x3977220 <line:2:7, col:14>
    `-IntegerLiteral 0x3977200 <col:14> 'int' 2
~/astprint/install/../test.c:1:3->3:4

ast-printer> 2
ReturnStmt 0x1ba3220 <test.c:2:7, col:14>
`-IntegerLiteral 0x1ba3200 <col:14> 'int' 2
~/astprint/install/../test.c:2:7->2:15

How to build

Requirements

• cmake >= 3.14
• Clang/LLVM 10 (cmake needs to find the installation, see the LLVM cmake documentation)
• C++ compiler with support for the C++17 standard, e.g., Clang-10

Build steps

In the root project folder, execute the following commands (see also CI build file)

cmake -B build -DCMAKE_INSTALL_PREFIX=*your path*
cmake --build build --target install --parallel