Hi, I've been playing with GCC plugins for a few weeks for static code analysis and source-to-source refactoring, and I figured a good first exercise would be to extract variable bindings, i.e. output a map that binds types/functions/variables usages to their declaration, with source code locations. A semantic etags, one may say - I know such tools already exist. I had a hard time figuring everything out due to the lack of documentation, but thanks to headers and helpful blog posts I am now able to walk the AST and registers entity declarations and their usages. However I have a few problem I can't seem to solve on my own despite intense googling, here are the two main ones: * I can retrieve source file location of declarations with DECL_SOURCE_LOCATION without any problem, but I can't get locations for expressions since their EXPR_LOCATION is always null. I used the PLUGIN_PRE_GENERICIZE hook, which AFAIK is the earliest, so I expected locations to still be there. Did I miss something, or is there no way to retrieve such locations from plugins, in which case my example seems impossible ? * Even if we suppose I fixed the previous issue, from what I inferred from the AST, a reference to a variable is directly represented by the corresponding VAR_DECL. That is, in "int x; int y; x + y;", "x + y" is a PLUS_EXPR whose operands are the VAR_DECL corresponding to "int x" and "int y". This would make it impossible for me to get the location of "x" and "y", since they are not represented as such by nodes in the AST. I fear that due to the compiler nature of GCC, the AST I'm working on is altered, with some processing and simplification already applied, preventing source-to-source code transformation since one cannot map ast chunks back to source files. Could anyone confirm or point me in some direction if I'm wrong ? In the case it's indeed impossible, is there any intent to improve this aspect, like giving access to earlier stages of the AST (freshly parsed, with only variable bindings for instance) ? This would enable to write extremely powerfull analysis & refactoring tools. Thanks in advance for your help, -- mefyl
