[review,v2,AArch64,SVE] Improve target description check for SVE in gdbserver
Commit Message
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/690
......................................................................
[AArch64, SVE] Improve target description check for SVE in gdbserver
The current code checks for the presence of a SVE target description by
comparing the number of registers. This is a bit fragile since the number
of registers can change whenever we add new sets. Like PAC, for example.
If the comparison breaks, then we're left with SVE registers in the
description, but gdbserver doesn't send the registers to GDB, which in
turn displays stale information to the user.
The following patch changes the check to use the SVE feature string instead,
which hopefully should be more stable.
gdb/gdbserver/ChangeLog:
2019-11-18 Luis Machado <luis.machado@linaro.org>
* linux-aarch64-low.c (is_sve_tdesc): Check against target feature
instead of register count.
* tdesc.c (tdesc_contains_feature): New function.
* tdesc.h (tdesc_contains_feature): New prototype.
Signed-off-by: Luis Machado <luis.machado@linaro.org>
Change-Id: I28b782cb1677560ca9a06a1be442974b25aabae4
---
M gdb/gdbserver/linux-aarch64-low.c
M gdb/gdbserver/tdesc.c
M gdb/gdbserver/tdesc.h
3 files changed, 24 insertions(+), 1 deletion(-)
@@ -83,7 +83,7 @@
{
struct regcache *regcache = get_thread_regcache (current_thread, 0);
- return regcache->tdesc->reg_defs.size () == AARCH64_SVE_NUM_REGS;
+ return tdesc_contains_feature (regcache->tdesc, "org.gnu.gdb.aarch64.sve");
}
static void
@@ -186,3 +186,20 @@
tdesc->features.emplace_back (new_feature);
return new_feature;
}
+
+/* See gdbsupport/tdesc.h. */
+
+bool
+tdesc_contains_feature (const target_desc *tdesc, const std::string feature)
+{
+ if (tdesc && !tdesc->features.empty ())
+ {
+ for (const tdesc_feature_up &f : tdesc->features)
+ {
+ if (f->name.compare (feature) == 0)
+ return true;
+ }
+ }
+
+ return false;
+}
@@ -93,4 +93,10 @@
const struct target_desc *current_target_desc (void);
+/* Return true if TDESC contains the feature described by string FEATURE.
+ If TDESC has no features or if the feature string FEATURE was not found in
+ TDESC, return false. */
+bool tdesc_contains_feature (const target_desc *tdesc,
+ const std::string feature);
+
#endif /* GDBSERVER_TDESC_H */