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* [PATCH] Return the regnum for PC (32) on aarch64
@ 2022-05-13 12:27 Yichao Yu
  2022-05-16  9:05 ` Luis Machado
  0 siblings, 1 reply; 17+ messages in thread
From: Yichao Yu @ 2022-05-13 12:27 UTC (permalink / raw)
  To: gdb-patches, Luis Machado

This will allow the unwind info to explicitly specify a different value
for the return address than the link register. Such usage, e.g. for signal frames,
is mentioned in aadwarf64 from ARM.

Ref https://sourceware.org/pipermail/gdb/2022-May/050091.html
---
 gdb/aarch64-tdep.c                           |  3 +
 gdb/aarch64-tdep.h                           |  1 +
 gdb/testsuite/gdb.arch/aarch64-unwind-pc.S   | 48 +++++++++++++++
 gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp | 63 ++++++++++++++++++++
 4 files changed, 115 insertions(+)
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-unwind-pc.S
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 9d06ebfe27c..f9eb455232f 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -2219,6 +2219,9 @@ aarch64_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
   if (reg == AARCH64_DWARF_SP)
     return AARCH64_SP_REGNUM;
 
+  if (reg == AARCH64_DWARF_PC)
+    return AARCH64_PC_REGNUM;
+
   if (reg >= AARCH64_DWARF_V0 && reg <= AARCH64_DWARF_V0 + 31)
     return AARCH64_V0_REGNUM + reg - AARCH64_DWARF_V0;
 
diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h
index e4cdebb6311..aa1bedbdac6 100644
--- a/gdb/aarch64-tdep.h
+++ b/gdb/aarch64-tdep.h
@@ -34,6 +34,7 @@ struct regset;
 /* AArch64 Dwarf register numbering.  */
 #define AARCH64_DWARF_X0   0
 #define AARCH64_DWARF_SP  31
+#define AARCH64_DWARF_PC  32
 #define AARCH64_DWARF_PAUTH_RA_STATE  34
 #define AARCH64_DWARF_PAUTH_DMASK  35
 #define AARCH64_DWARF_PAUTH_CMASK  36
diff --git a/gdb/testsuite/gdb.arch/aarch64-unwind-pc.S b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.S
new file mode 100644
index 00000000000..8589a64fd56
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.S
@@ -0,0 +1,48 @@
+/* Copyright 2022-2022 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+        .text
+        .globl main
+        .type main,#function
+main:
+        .cfi_startproc
+        stp     x29, x30, [sp, -16]!
+        .cfi_def_cfa sp, 16
+        .cfi_offset x29, 0
+        .cfi_offset x30, 8
+        bl test_func
+        ldp     x29, x30, [sp], 16
+        .cfi_restore x29
+        .cfi_restore x30
+        .cfi_def_cfa sp, 0
+        mov     x0, 0
+        ret
+        .cfi_endproc
+
+        .globl test_func
+test_func:
+        .cfi_startproc
+        // Unwind x30 to a different value
+        // CFA_val_expression x30 const2u 0x1234
+        .cfi_escape 0x16, 30, 0x03, 0x0a, 0x34, 0x12
+        // CFA_val_expression pc breg30 0
+        .cfi_escape 0x16, 32, 0x02, 0x8e, 0x00
+        mov     x0, x30
+        .cfi_register 32, x0
+        mov     x30, 0x1234
+        ret     x0
+        .cfi_endproc
diff --git a/gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp
new file mode 100644
index 00000000000..c047c7d2f1a
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-unwind-pc.exp
@@ -0,0 +1,63 @@
+# Copyright 2022-2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+# Test explicitly unwinding PC on aarch64
+
+if {![is_aarch64_target]} then {
+    verbose "Skipping arm displaced stepping tests."
+    return
+}
+
+standard_testfile .S
+
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } {
+    return -1
+}
+
+if ![runto_main] {
+    return -1
+}
+
+proc test_reg_vals { i } {
+    gdb_test "p \$pc - &main" "= 8" "p \$pc, $i"
+    gdb_test "p \$x30" "= 4660" "p \$x30, $i"
+}
+
+proc test_unwind_pc { i } {
+    gdb_test "si" "" "single step, $i"
+    gdb_test "backtrace" \
+	".*#1.*in main ().*" \
+	"backtrace, $i"
+    gdb_test "up" "" "parent frame, $i"
+    test_reg_vals "$i"
+}
+
+# Ready to enter the function
+gdb_test "si" "bl test_func" "call site"
+# Step through the 3 instructions in the function to make sure that
+# we have the same unwind info throughout.
+test_unwind_pc 1
+test_unwind_pc 2
+test_unwind_pc 3
+# Check again after we returned
+gdb_test "si" "" "single step out"
+gdb_test "backtrace" \
+    "#0\[\t \]+main ().*" \
+    "backtrace, 4"
+test_reg_vals 4
+
+gdb_continue_to_end "aarch64-unwind-pc"
-- 
2.36.1


^ permalink raw reply	[flat|nested] 17+ messages in thread

end of thread, other threads:[~2022-05-19  1:12 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-13 12:27 [PATCH] Return the regnum for PC (32) on aarch64 Yichao Yu
2022-05-16  9:05 ` Luis Machado
2022-05-16 13:17   ` Yichao Yu
2022-05-16 13:25     ` [PATCH v2] " Yichao Yu
2022-05-17  6:42       ` Luis Machado
2022-05-17 14:41         ` [PATCH v3] " Yichao Yu
2022-05-17 17:34         ` [PATCH v2] " Yichao Yu
2022-05-17 17:36           ` [PATCH v3] " Yichao Yu
2022-05-18  1:03             ` Yichao Yu
2022-05-18  9:53               ` Luis Machado
2022-05-18 13:01                 ` Yichao Yu
2022-05-18 13:36                   ` Luis Machado
2022-05-18 14:01                     ` Yichao Yu
2022-05-18 14:03                       ` Luis Machado
2022-05-19  1:11                         ` Yichao Yu
2022-05-16 13:29     ` [PATCH] " Luis Machado
2022-05-16 14:10       ` Yichao Yu

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