Re: adding nodes in a tree --after GIMPLIFICATION, before SSA

[Daniel Berlin <dberlin at dberlin dot org>]

On Apr 18, 2006, at 7:28 PM, sean yang wrote:

> I will appreciate your help. Thanks in advance.
>
> Let me give a concrete example of what I want to do (Please  
> understand I have other reasons to do this after gimplification,  
> though the example shows that there is a much simpler way to  
> achieve this):  in the example, I want to add a call of instrument 
> () after each call of foo()
> -----------------------
> //input source: example.c
> main(){
>   int i=0;
>   foo();
>   i++;
>   bar();
> }
> -----------------------------
> //conceptual source: with my compiler, the output should look like  
> the output of the following source code
> main(){
>   int i=0;
>   foo();
>   instrument(); //i.e, adding a node of CALL_EXPR (instrument)  
> after each node CALL_EXPR (foo)
>   i++;
>   bar();
> }
> -----------------------------
>
> What I want to do is whenever I find a CALL_EXPR node, I look up  
> its ID to see if it is "foo". If it is, I add another CALL_EXPR  
> node with ID of "instrument". I have two questions:
> (1) I know "call_node = build (CALL_EXPR, tree_node)" can build a  
> new node, but how can I fill the field of tree_node properly? i.e.,  
> make the content of tree_node be a call to "instrument". It seems  
> there is no API to do so.

You really want build_function_call_expr to build the call itself, it  
takes a function decl and the argument list.

To build a function_decl, use build_decl (FUNCTION_DECL,  
get_identifier ("name"), type);


If it returns a value, you want to build a modify_expr with the first  
argument being the return value to assign to, and the second argument  
being the result of build_function_call_expr.

> (2) after the node the call_node has been built, how can I added to  
> the proper place? It seems that tsi_link_after () can't do what I  
> want under this situation because it's only used for  
> STATEMENT_LIST, not other type of nodes, like CALL_EXPR.
Actually, it would work fine, but it's not the right thing.

use bsi_from_stmt to get a bsi for the thing you are isnerting before/ 
after, and use bsi_insert_before/bsi_insert_after.

You really should be looking at tree-nested, tree-profile, omp-low, etc.
They all do this sort of thing