gas: allow labeling of CFI instructions

When runtime patching code (like e.g. done by the Linux kernel) there
may be cases where the set of stack frame alterations differs between
unpatched and patched code. Consequently the corresponding unwind data
needs patching too. Locating the right places within an FDE, however,
is rather cumbersome without a way to insert labels in the resulting
section. Hence this patch introduces a new directive, .cfi_label. Note
that with the way CFI data gets emitted currently (at the end of the
assembly process) this can't support local FB- and dollar-labels.

gas/
2015-01-12  Jan Beulich  <jbeulich@suse.com>

	* gas/dw2gencfi.c (cfi_add_label, dot_cfi_label): New.
	(cfi_pseudo_table): Add "cfi_label".
	(output_cfi_insn): Handle CFI_label.
	(select_cie_for_fde): Als terminate CIE when encountering
	CFI_label.
	* dw2gencfi.h (cfi_add_label): Declare.
	(struct cfi_insn_data): New member "sym_name".
	(CFI_label): New.
	* read.c (read_symbol_name): Drop "static".
	* read.h (read_symbol_name): Declare.

gas/testsuite/
2015-01-12  Jan Beulich  <jbeulich@suse.com>

	gas/cfi/cfi-label.d, gas/cfi/cfi-label.s: New.
	gas/cfi/cfi.exp: Run new tests.

1 files changed, 1 insertions, 0 deletions

diff --git a/gas/read.h b/gas/read.h
index 32d3767..d7ac6ce 100644
--- a/gas/read.h
+++ b/gas/read.h
@@ -127,6 +127,7 @@ extern void pseudo_set (symbolS * symbolP);
 extern void read_a_source_file (char *name);
 extern void read_begin (void);
 extern void read_print_statistics (FILE *);
+extern char *read_symbol_name (void);
 extern int sizeof_leb128 (valueT, int sign);
 extern void stabs_generate_asm_file (void);
 extern void stabs_generate_asm_lineno (void);