Relation between Roles and Transaction Company Code

Then you have to see tables USR02 , TSTC ..

Well . you can also see list of reports in T-code SUIM
Tha way it looks like to me is that he is looking for the authorization values. All the user authorization values are stored in the table UST12. You can get the values of say tcode for which the user is authorized, by calling the function module SUSR_USER_AUTH_FOR_OBJ_GET and passing user name and 'S_TCODE' for 'SEL_OBJECT'.

But for company code, this becomes very complicated because, you may authorized to perform a certain action for a certain company code, in a particular transaction. But for the same company code, in another transaction, you may not be able to do any aciton. You really need to know which authorization object each transaction is checking that has BUKRS as field.
Do you mean user roles? If so, perhaps transaction SUIM and change documents can help you...
Create Roles
The role also contains the authorizations users need to access the transactions, reports, web-based applications and so on, contained in the menu.
You can assign a role to an unlimited number of users.
Procedure
To create a single role:
1. Choose the pushbutton Create role or the transaction PFCG in the initial transaction SAP Easy Access. You go to the role maintenance.
2. Specify a name for the role.
The roles delivered by SAP have the prefix 'SAP_'. Do not use the SAP namespace for your user roles.
SAP does not distinguish between the names of simple and composite roles. You should adopt your own naming convention to distinguish between simple and composite roles.
3. Choose Basic maintenance (in the Profile, Other objects menu).
4. Choose Create.
5. Enter a meaningful role description text. You can describe the activities in the role in detail.
you can find the relationship between users and roles in table AGR_USERS.