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Hello, A collegue of mine recently complained that inferior function calls on amd64 where often leading to a SIGSEGV in the inferior. Most notably, he was trying to call a function in GCC that, given a node ID (a simple number), prints everything about that node. Once I understood the source of the problem, I was able to reproduce it with a much smaller example. Unfortunately, it has to be in Ada, because it involves range types. Here is the code: << package Pck is type Node_Id is new Integer range 0 .. Integer'Last; procedure Print_Node (N : Node_Id); end Pck; with Ada.Text_IO; use Ada.Text_IO; package body Pck is procedure Pn (N: Node_Id); pragma Export (C, Pn, "pn"); -- Another wrapper around Print_Node exported via "pragma Export C" -- to allow us to easily call it from a C debugger. ---------------- -- Print_Node -- ---------------- procedure Print_Node (N : Node_Id) is begin Put_Line ("Node:" & Node_Id'Image (N)); end Print_Node; -------- -- Pn -- -------- procedure Pn (N: Node_Id) is begin Print_Node (N); end Pn; end Pck; with Pck; use Pck; procedure Foo is begin Print_Node (1); end Foo; >> Compile it using the following command: % gnatmake -g foo The debug it with GDB (doesn't have to be an Ada-aware debugger): (gdb) list foo.adb:1 1 with Pck; use Pck; 2 3 procedure Foo is 4 begin 5 Print_Node (1); 6 end Foo; (gdb) b foo.adb:5 Breakpoint 1 at 0x4024f4: file foo.adb, line 5. (gdb) run Starting program: /don.a/brobecke/calling_pb/foo Breakpoint 1, _ada_foo () at foo.adb:5 5 Print_Node (1); Current language: auto; currently minimal (gdb) call pn (1234) !!! -> Node:-1786175552 The last line is incorrect. The node ID should be 1234. The problem is that type Node_Id is a 4 bytes range type. Procedure "Pn" expects this parameter to be passed via %rdi. But there is a slight omission in amd64_classify that does not classifies RANGE_TYPE entities in the INTEGER class. The attached patch fixes this. 2004-02-24 J. Brobecker <brobecker@gnat.com> * amd64-tdep.c (amd64_classify): make RANGE_TYPE objects be part of the INTEGER class. Tested on amd64-linux. No regression. Ok to apply? Thanks, -- Joel
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