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From: Andrew Burgess <aburgess@redhat.com>
To: gdb-patches@sourceware.org
Subject: [PATCH 5/9] gdb: check for duplicate register names in selftest
Date: Thu,  1 Sep 2022 22:31:13 +0100	[thread overview]
Message-ID: <7c3f810e976d03e516956492a16a8ae2948e3023.1662067442.git.aburgess@redhat.com> (raw)
In-Reply-To: <cover.1662067442.git.aburgess@redhat.com>

Building on the previous commit, this commit extends the register_name
selftest to check for duplicate register names.

If two registers in the cooked register set (real + pseudo registers)
have the same name, then this will show up as duplicate registers in
the 'info all-registers' output, but the user will only be able to
interact with one copy of the register.

In this commit I extend the selftest that I added in the previous
commit to check for duplicate register names, I didn't include this
functionality in the previous commit because one architecture needed
fixing, and I wanted to keep those fixes separate from the fixes in
the previous commit.

The problematic architecture(s) are powerpc:750 and powerpc:604.  In
both of these cases the 'dabr' register appears twice, there's a
definition of dabr in power-oea.xml which is included into both
powerpc-604.xml and powerpc-750.xml.  Both of these later two xml
files also define the dabr register.

I'm hopeful that this change shouldn't break anything, but I don't
have the ability to actually test this change, however:

On the gdbserver side, neither powerpc-604.xml nor powerpc-750.xml are
mentioned in gdbserver/configure.srv, which I think means that
gdbserver will never use these descriptions, and,

Within GDB the problematic descriptions are held in the variables
tdesc_powerpc_604 and tdesc_powerpc_750, which are only mentioned in
the variants array in rs6000-tdep.c, this is used when looking up a
description based on the architecture.

For a native Linux target however, this will not be used as
ppc_linux_nat_target::read_description exists, which calls
ppc_linux_match_description, which I don't believe can return either
of the problematic descriptions.

This leaves the other native targets, FreeBSD, AIX, etc.  These don't
appear to override the ::read_description method, so will potentially
return the problematic descriptions, but, in each case I think the
::fetch_registers and ::store_registers methods will ignore the dabr
register, which will leave the register as <unavailable>.

So, my proposed solution is to just remove the duplicate register from
each of powerpc-604.xml and powerpc-750.xml, then regenerate the
corresponding C++ source file.  With this change made, the selftest
now passes for all architectures.
---
 gdb/features/rs6000/powerpc-604.c   | 13 ++++++-------
 gdb/features/rs6000/powerpc-604.xml |  1 -
 gdb/features/rs6000/powerpc-750.c   |  1 -
 gdb/features/rs6000/powerpc-750.xml |  1 -
 gdb/gdbarch-selftests.c             | 21 ++++++++++++++++++++-
 5 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/gdb/features/rs6000/powerpc-604.c b/gdb/features/rs6000/powerpc-604.c
index fe0fe2fc7e4..474b29fed55 100644
--- a/gdb/features/rs6000/powerpc-604.c
+++ b/gdb/features/rs6000/powerpc-604.c
@@ -141,13 +141,12 @@ initialize_tdesc_powerpc_604 (void)
   tdesc_create_reg (feature, "hid0", 119, 1, NULL, 32, "int");
   tdesc_create_reg (feature, "hid1", 120, 1, NULL, 32, "int");
   tdesc_create_reg (feature, "iabr", 121, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "dabr", 122, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "pir", 123, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "mmcr0", 124, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "pmc1", 125, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "pmc2", 126, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "sia", 127, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "sda", 128, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "pir", 122, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "mmcr0", 123, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "pmc1", 124, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "pmc2", 125, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "sia", 126, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "sda", 127, 1, NULL, 32, "int");
 
   tdesc_powerpc_604 = result.release ();
 }
diff --git a/gdb/features/rs6000/powerpc-604.xml b/gdb/features/rs6000/powerpc-604.xml
index fbc9e946d22..052cfbb7e76 100644
--- a/gdb/features/rs6000/powerpc-604.xml
+++ b/gdb/features/rs6000/powerpc-604.xml
@@ -17,7 +17,6 @@
     <reg name="hid0" bitsize="32"/>
     <reg name="hid1" bitsize="32"/>
     <reg name="iabr" bitsize="32"/>
-    <reg name="dabr" bitsize="32"/>
     <reg name="pir" bitsize="32"/>
     <reg name="mmcr0" bitsize="32"/>
     <reg name="pmc1" bitsize="32"/>
diff --git a/gdb/features/rs6000/powerpc-750.c b/gdb/features/rs6000/powerpc-750.c
index 396ec456651..3533c42d6cb 100644
--- a/gdb/features/rs6000/powerpc-750.c
+++ b/gdb/features/rs6000/powerpc-750.c
@@ -141,7 +141,6 @@ initialize_tdesc_powerpc_750 (void)
   tdesc_create_reg (feature, "hid0", 119, 1, NULL, 32, "int");
   tdesc_create_reg (feature, "hid1", 120, 1, NULL, 32, "int");
   tdesc_create_reg (feature, "iabr", 121, 1, NULL, 32, "int");
-  tdesc_create_reg (feature, "dabr", 122, 1, NULL, 32, "int");
   tdesc_create_reg (feature, "ummcr0", 124, 1, NULL, 32, "int");
   tdesc_create_reg (feature, "upmc1", 125, 1, NULL, 32, "int");
   tdesc_create_reg (feature, "upmc2", 126, 1, NULL, 32, "int");
diff --git a/gdb/features/rs6000/powerpc-750.xml b/gdb/features/rs6000/powerpc-750.xml
index 908ecbdfd96..dfc5a87aaa0 100644
--- a/gdb/features/rs6000/powerpc-750.xml
+++ b/gdb/features/rs6000/powerpc-750.xml
@@ -17,7 +17,6 @@
     <reg name="hid0" bitsize="32"/>
     <reg name="hid1" bitsize="32"/>
     <reg name="iabr" bitsize="32"/>
-    <reg name="dabr" bitsize="32"/>
     <reg name="ummcr0" bitsize="32" regnum="124"/>
     <reg name="upmc1" bitsize="32"/>
     <reg name="upmc2" bitsize="32"/>
diff --git a/gdb/gdbarch-selftests.c b/gdb/gdbarch-selftests.c
index 75a3109143f..9bb00c93ff0 100644
--- a/gdb/gdbarch-selftests.c
+++ b/gdb/gdbarch-selftests.c
@@ -27,6 +27,8 @@
 #include "gdbarch.h"
 #include "scoped-mock-context.h"
 
+#include <map>
+
 namespace selftests {
 
 /* Test gdbarch methods register_to_value and value_to_register.  */
@@ -129,6 +131,9 @@ register_name_test (struct gdbarch *gdbarch)
 {
   scoped_mock_context<test_target_ops> mockctx (gdbarch);
 
+  /* Track the number of times each register name appears.  */
+  std::map<const std::string, int> name_counts;
+
   const int num_regs = gdbarch_num_cooked_regs (gdbarch);
   for (auto regnum = 0; regnum < num_regs; regnum++)
     {
@@ -141,8 +146,22 @@ register_name_test (struct gdbarch *gdbarch)
 	debug_printf ("arch: %s, register: %d returned nullptr\n",
 		      gdbarch_bfd_arch_info (gdbarch)->printable_name,
 		      regnum);
-
       SELF_CHECK (name != nullptr);
+
+      /* Every register name, that is not the empty string, should be
+	 unique.  If this is not the case then the user will see duplicate
+	 copies of the register in e.g. 'info registers' output, but will
+	 only be able to interact with one of the copies.  */
+      if (*name != '\0')
+	{
+	  std::string s (name);
+	  name_counts[s]++;
+	  if (run_verbose() && name_counts[s] > 1)
+	    debug_printf ("arch: %s, register: %d (%s) is a duplicate\n",
+			  gdbarch_bfd_arch_info (gdbarch)->printable_name,
+			  regnum, name);
+	  SELF_CHECK (name_counts[s] == 1);
+	}
     }
 }
 
-- 
2.25.4


  parent reply	other threads:[~2022-09-01 21:31 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-01 21:31 [PATCH 0/9] Lots of changes to gdbarch_register_name (many architectures) Andrew Burgess
2022-09-01 21:31 ` [PATCH 1/9] gdb/testsuite: rewrite capture_command_output proc Andrew Burgess
2022-09-01 21:31 ` [PATCH 2/9] gdb/riscv: fix failure in gdb.base/completion.exp Andrew Burgess
2022-09-01 21:31 ` [PATCH 3/9] gdb/gdbarch: add a comment to gdbarch_register_name Andrew Burgess
2022-09-01 21:31 ` [PATCH 4/9] gdb: add a gdbarch_register_name self test, and fix some architectures Andrew Burgess
2022-09-01 21:31 ` Andrew Burgess [this message]
2022-09-01 21:31 ` [PATCH 6/9] gdb: add asserts to gdbarch_register_name Andrew Burgess
2022-09-21 18:04   ` Tom Tromey
2022-09-01 21:31 ` [PATCH 7/9] gdb/csky: remove nullptr return from csky_pseudo_register_name Andrew Burgess
2022-09-01 21:31 ` [PATCH 8/9] gdb: final cleanup of various gdbarch_register_name methods Andrew Burgess
2022-09-01 21:31 ` [PATCH 9/9] gdb: update now gdbarch_register_name doesn't return nullptr Andrew Burgess
2022-09-21 18:07 ` [PATCH 0/9] Lots of changes to gdbarch_register_name (many architectures) Tom Tromey
2022-10-02 16:28   ` Andrew Burgess

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