CFI support: lookup by PC and translate into DWARF location per register

1 files changed, 33 insertions, 1 deletions

diff --git a/libebl/libebl.h b/libebl/libebl.h
index 50258690..1a56b966 100644
--- a/libebl/libebl.h
+++ b/libebl/libebl.h
@@ -1,5 +1,5 @@
 /* Interface for libebl.
-   Copyright (C) 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008 Red Hat, Inc.
+   Copyright (C) 2000, 2001-2009 Red Hat, Inc.
    This file is part of Red Hat elfutils.
 
    Red Hat elfutils is free software; you can redistribute it and/or modify
@@ -256,6 +256,38 @@ extern ssize_t ebl_register_info (Ebl *ebl,
 extern int ebl_syscall_abi (Ebl *ebl, int *sp, int *pc,
 			    int *callno, int args[6]);
 
+/* Supply the ABI-specified state of DWARF CFI before CIE initial programs.
+
+   The DWARF 3.0 spec says that the default initial states of all registers
+   are "undefined", unless otherwise specified by the machine/compiler ABI.
+
+   This default is wrong for every machine with the CFI generated by GCC.
+   The EH unwinder does not really distinguish "same_value" and "undefined",
+   since it doesn't matter for unwinding (in either case there is no change
+   to make for that register).  GCC generates CFI that says nothing at all
+   about registers it hasn't spilled somewhere.  For our unwinder to give
+   the true story, the backend must supply an initial state that uses
+   "same_value" rules for all the callee-saves registers.
+
+   This can fill in the initial_instructions, initial_instructions_end
+   members of *ABI_INFO to point at a CFI instruction stream to process
+   before each CIE's initial instructions.  It should set the
+   data_alignment_factor member if it affects the initial instructions.
+
+   As a shorthand for some common cases, for this instruction stream
+   we overload some CFI instructions that cannot be used in a CIE:
+
+	DW_CFA_restore		-- Change default rule for all unmentioned
+				   registers from undefined to same_value.
+
+   This function can also fill in ABI_INFO->return_address_register with the
+   DWARF register number that identifies the actual PC in machine state.
+   If there is no canonical DWARF register number with that meaning, it's
+   left unchanged (callers usually initialize with (Dwarf_Word) -1).
+   This value is not used by CFI per se.  */
+extern int ebl_abi_cfi (Ebl *ebl, Dwarf_CIE *abi_info)
+  __nonnull_attribute__ (2);
+
 /* ELF string table handling.  */
 struct Ebl_Strtab;
 struct Ebl_Strent;