Use aarch64_features to describe register features in target descriptions.

Replace the sve bool member of aarch64_features with a vq member that
holds the vector quotient.  It is zero if SVE is not present.

Add std::hash<> specialization and operator== so that aarch64_features
can be used as a key with std::unordered_map<>.

Change the various functions that create or lookup aarch64 target
descriptions to accept a const aarch64_features object rather than a
growing number of arguments.

Replace the multi-dimension tdesc_aarch64_list arrays used to cache
target descriptions with unordered_maps indexed by aarch64_feature.

5 files changed, 20 insertions, 21 deletions

diff --git a/gdbserver/linux-aarch64-ipa.cc b/gdbserver/linux-aarch64-ipa.cc
index dc907d3ff8..918f85f6ea 100644
--- a/gdbserver/linux-aarch64-ipa.cc
+++ b/gdbserver/linux-aarch64-ipa.cc
@@ -152,7 +152,7 @@ get_raw_reg (const unsigned char *raw_regs, int regnum)
 const struct target_desc *
 get_ipa_tdesc (int idx)
 {
-  return aarch64_linux_read_description (0, false, false, false);
+  return aarch64_linux_read_description ({});
 }
 
 /* Allocate buffer for the jump pads.  The branch instruction has a reach
@@ -205,5 +205,5 @@ void
 initialize_low_tracepoint (void)
 {
   /* SVE, pauth, MTE and TLS not yet supported.  */
-  aarch64_linux_read_description (0, false, false, false);
+  aarch64_linux_read_description ({});
 }
diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
index ba0a810e0f..db50869626 100644
--- a/gdbserver/linux-aarch64-low.cc
+++ b/gdbserver/linux-aarch64-low.cc
@@ -779,11 +779,11 @@ aarch64_adjust_register_sets (const struct aarch64_features &features)
 	  break;
 	case NT_FPREGSET:
 	  /* This is unavailable when SVE is present.  */
-	  if (!features.sve)
+	  if (features.vq == 0)
 	    regset->size = sizeof (struct user_fpsimd_state);
 	  break;
 	case NT_ARM_SVE:
-	  if (features.sve)
+	  if (features.vq > 0)
 	    regset->size = SVE_PT_SIZE (AARCH64_MAX_SVE_VQ, SVE_PT_REGS_SVE);
 	  break;
 	case NT_ARM_PAC_MASK:
@@ -824,17 +824,14 @@ aarch64_target::low_arch_setup ()
     {
       struct aarch64_features features;
 
-      uint64_t vq = aarch64_sve_get_vq (tid);
-      features.sve = (vq > 0);
+      features.vq = aarch64_sve_get_vq (tid);
       /* A-profile PAC is 64-bit only.  */
       features.pauth = linux_get_hwcap (8) & AARCH64_HWCAP_PACA;
       /* A-profile MTE is 64-bit only.  */
       features.mte = linux_get_hwcap2 (8) & HWCAP2_MTE;
       features.tls = true;
 
-      current_process ()->tdesc
-	= aarch64_linux_read_description (vq, features.pauth, features.mte,
-					  features.tls);
+      current_process ()->tdesc = aarch64_linux_read_description (features);
 
       /* Adjust the register sets we should use for this particular set of
 	 features.  */
diff --git a/gdbserver/linux-aarch64-tdesc.cc b/gdbserver/linux-aarch64-tdesc.cc
index be96612d57..93f2bedde0 100644
--- a/gdbserver/linux-aarch64-tdesc.cc
+++ b/gdbserver/linux-aarch64-tdesc.cc
@@ -25,36 +25,36 @@
 #include "arch/aarch64.h"
 #include "linux-aarch32-low.h"
 #include <inttypes.h>
+#include <unordered_map>
 
 /* All possible aarch64 target descriptors.  */
-struct target_desc *tdesc_aarch64_list[AARCH64_MAX_SVE_VQ + 1][2/*pauth*/][2 /* mte */][2 /* tls */];
+static std::unordered_map<aarch64_features, target_desc *> tdesc_aarch64_map;
 
 /* Create the aarch64 target description.  */
 
 const target_desc *
-aarch64_linux_read_description (uint64_t vq, bool pauth_p, bool mte_p,
-				bool tls_p)
+aarch64_linux_read_description (const aarch64_features &features)
 {
-  if (vq > AARCH64_MAX_SVE_VQ)
-    error (_("VQ is %" PRIu64 ", maximum supported value is %d"), vq,
+  if (features.vq > AARCH64_MAX_SVE_VQ)
+    error (_("VQ is %" PRIu64 ", maximum supported value is %d"), features.vq,
 	   AARCH64_MAX_SVE_VQ);
 
-  struct target_desc *tdesc = tdesc_aarch64_list[vq][pauth_p][mte_p][tls_p];
+  struct target_desc *tdesc = tdesc_aarch64_map[features];
 
   if (tdesc == NULL)
     {
-      tdesc = aarch64_create_target_description (vq, pauth_p, mte_p, tls_p);
+      tdesc = aarch64_create_target_description (features);
 
       static const char *expedite_regs_aarch64[] = { "x29", "sp", "pc", NULL };
       static const char *expedite_regs_aarch64_sve[] = { "x29", "sp", "pc",
 							 "vg", NULL };
 
-      if (vq == 0)
+      if (features.vq == 0)
 	init_target_desc (tdesc, expedite_regs_aarch64);
       else
 	init_target_desc (tdesc, expedite_regs_aarch64_sve);
 
-      tdesc_aarch64_list[vq][pauth_p][mte_p][tls_p] = tdesc;
+      tdesc_aarch64_map[features] = tdesc;
     }
 
   return tdesc;
diff --git a/gdbserver/linux-aarch64-tdesc.h b/gdbserver/linux-aarch64-tdesc.h
index 4ab658447a..30bcd24d13 100644
--- a/gdbserver/linux-aarch64-tdesc.h
+++ b/gdbserver/linux-aarch64-tdesc.h
@@ -20,7 +20,9 @@
 #ifndef GDBSERVER_LINUX_AARCH64_TDESC_H
 #define GDBSERVER_LINUX_AARCH64_TDESC_H
 
-const target_desc * aarch64_linux_read_description (uint64_t vq, bool pauth_p,
-						    bool mte_p, bool tls_p);
+#include "arch/aarch64.h"
+
+const target_desc *
+  aarch64_linux_read_description (const aarch64_features &features);
 
 #endif /* GDBSERVER_LINUX_AARCH64_TDESC_H */
diff --git a/gdbserver/netbsd-aarch64-low.cc b/gdbserver/netbsd-aarch64-low.cc
index b371e59923..f8447b0d1e 100644
--- a/gdbserver/netbsd-aarch64-low.cc
+++ b/gdbserver/netbsd-aarch64-low.cc
@@ -96,7 +96,7 @@ void
 netbsd_aarch64_target::low_arch_setup ()
 {
   target_desc *tdesc
-    = aarch64_create_target_description (0, false, false, false);
+    = aarch64_create_target_description ({});
 
   static const char *expedite_regs_aarch64[] = { "x29", "sp", "pc", NULL };
   init_target_desc (tdesc, expedite_regs_aarch64);