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acb66ce9d2
Refactor the SFrame textual dumper in sframe-dump.c to properly handle
the new FDE type.
In SFrame V2, the textual dumper could afford to be oblivious to the
exact DWARF register number for stack-pointer and frame-pointer
registers in each ABI. This is because a single bit was used to
differentiate between the two (irrespective of the ABI), and the dumper
could easily just use a:
const char *base_reg_str[] = {"fp", "sp"};
to get the register name.
With the introduction of new SFrame FDE type SFRAME_FDE_TYPE_FLEX, which
carry DWARF register numbers if applicable, this needs to change. E.g.,
for some patterns on AMD64, one may see CFA is the value at 'r10+0'; or
FP is the value at 'rbp+8'. This means that for textual dump, we now
need a mapping from:
- the ABI-specific frame-pointer to string "fp"
- the ABI-specific stack-pointer to string "sp"
This is done via the SFRAME_ABI_REG_MAP helper macros and the new
sframe_get_reg_name () API.
For registers other than stack-pointer and frame-pointer, the SFrame
textual dump does not print the register name (say, "rax"), but just the
number (i.e., "r0").
Check the func_info2 byte and dispatch the stack frame row entry (FRE)
dumping to the correct function: either dump_sframe_func_fre_simple or
dump_sframe_func_fre_flex.
Ensure the display is consistent to previous semantics. When flex FDE
is in effect, there may not always be an RA offset (after the CFA
offsets). A padding offset for RA is present if FP offsets follow. So
if a padding offset for RA is seen, we will display "U". If no RA
offset is seen, however, we will display a "u" unless its an ABI where
RA offset is fixed (in the latter case we display "f").
libsframe/
* sframe-dump.c (SFRAME_SP): Define mapping from stack-pointer
register number to "sp".
(SFRAME_FP): Define mapping from frame-pointer register number
to "fp".
(SFRAME_ABI_REG_MAP): Helper macro to define per-ABI-arch
mappings.
(sframe_get_reg_name): Helper API to get register name.
(dump_sframe_func_with_fres): Refactor a bit...
(dump_sframe_func_fre_simple): ..into this.
(sframe_format_fre_disp): New definition.
(dump_sframe_func_fre_flex): Likewise.
(dump_sframe): Allow both SFrame version 2 and version 3.
libsframe is a support library for the GNU Binutils collection (currently used by GNU ld, objdump, etc.) to read and write SFrame section data. Note: This library is currently intended for internal use by GNU Binutils only. Strict guarantees for ABI compatibility are not provided, and external projects should not rely on the stability of these interfaces.