Fix PR30369 regression on aarch64/arm (PR30506)

The gdb.dwarf2/dw2-prologue-end-2.exp test was failing for both AArch64 and
Arm.

As Tom pointed out here (https://inbox.sourceware.org/gdb-patches/6663707c-4297-c2f2-a0bd-f3e84fc62aad@suse.de/),
there are issues with both the prologue skipper for AArch64 and Arm and an
incorrect assumption by the testcase.

This patch fixes both of AArch64's and Arm's prologue skippers to not skip past
the end of a function.  It also incorporates a fix to the testcase so it
doesn't assume the prologue skipper will stop at the first instruction of the
functions/labels.

Regression-tested on aarch64-linux/arm-linux Ubuntu 20.04/22.04 and
x86_64-linux Ubuntu 20.04.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30506

Co-Authored-By: Tom de Vries <tdevries@suse.de>
Co-Authored-By: Luis Machado <luis.machado@arm.com>

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index d8603c45fd34abd29818a38be8402fd49044d6b7..84a90b63b55ce49bb2852c6b9a2eee145e598994 100644 (file)
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -917,12 +917,15 @@ aarch64_analyze_prologue_test (void)
 static CORE_ADDR
 aarch64_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 {
-  CORE_ADDR func_addr, limit_pc;
+  CORE_ADDR func_addr, func_end_addr, limit_pc;
 
   /* See if we can determine the end of the prologue via the symbol
      table.  If so, then return either PC, or the PC after the
      prologue, whichever is greater.  */
-  if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
+  bool func_addr_found
+    = find_pc_partial_function (pc, NULL, &func_addr, &func_end_addr);
+
+  if (func_addr_found)
     {
       CORE_ADDR post_prologue_pc
        = skip_prologue_using_sal (gdbarch, func_addr);
@@ -942,6 +945,9 @@ aarch64_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
   if (limit_pc == 0)
     limit_pc = pc + 128;       /* Magic.  */
 
+  limit_pc
+    = func_end_addr == 0? limit_pc : std::min (limit_pc, func_end_addr - 4);
+
   /* Try disassembling prologue.  */
   return aarch64_analyze_prologue (gdbarch, pc, limit_pc, NULL);
 }

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index d5128754f0220b6e7af3170099bfab59f6c58e53..a0f59557072ba4dc3ad28fb0035189969ff7f0c9 100644 (file)
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -1769,12 +1769,18 @@ arm_skip_stack_protector(CORE_ADDR pc, struct gdbarch *gdbarch)
 static CORE_ADDR
 arm_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 {
-  CORE_ADDR func_addr, limit_pc;
+  CORE_ADDR func_addr, func_end_addr, limit_pc;
 
   /* See if we can determine the end of the prologue via the symbol table.
      If so, then return either PC, or the PC after the prologue, whichever
      is greater.  */
-  if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
+  bool func_addr_found
+    = find_pc_partial_function (pc, NULL, &func_addr, &func_end_addr);
+
+  /* Whether the function is thumb mode or not.  */
+  bool func_is_thumb = false;
+
+  if (func_addr_found)
     {
       CORE_ADDR post_prologue_pc
        = skip_prologue_using_sal (gdbarch, func_addr);
@@ -1811,7 +1817,8 @@ arm_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
             associate prologue code with the opening brace; so this
             lets us skip the first line if we think it is the opening
             brace.  */
-         if (arm_pc_is_thumb (gdbarch, func_addr))
+         func_is_thumb = arm_pc_is_thumb (gdbarch, func_addr);
+         if (func_is_thumb)
            analyzed_limit = thumb_analyze_prologue (gdbarch, func_addr,
                                                     post_prologue_pc, NULL);
          else
@@ -1837,6 +1844,14 @@ arm_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
   if (limit_pc == 0)
     limit_pc = pc + 64;          /* Magic.  */
 
+  /* Set the correct adjustment based on whether the function is thumb mode or
+     not.  We use it to get the address of the last instruction in the
+     function (as opposed to the first address of the next function).  */
+  CORE_ADDR adjustment = func_is_thumb? 2 : 4;
+
+  limit_pc
+    = func_end_addr == 0? limit_pc : std::min (limit_pc,
+                                              func_end_addr - adjustment);
 
   /* Check if this is Thumb code.  */
   if (arm_pc_is_thumb (gdbarch, pc))

diff --git a/gdb/testsuite/gdb.dwarf2/dw2-prologue-end-2.exp b/gdb/testsuite/gdb.dwarf2/dw2-prologue-end-2.exp
index 488f85f9674f2be3ce517c78c1568907b3743bea..e1872ebea168506f395d6f4abdcf018ccf9096ec 100644 (file)
--- a/gdb/testsuite/gdb.dwarf2/dw2-prologue-end-2.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-prologue-end-2.exp
@@ -93,17 +93,17 @@ if { $break_addr == "" } {
     return
 }
 
-# Get the "foo_label" address.
+# Get the "bar_label" address.
 
-set foo_label_addr ""
-gdb_test_multiple "print /x &foo_label" "" {
+set bar_label_addr ""
+gdb_test_multiple "print /x &bar_label" "" {
     -re -wrap "= ($hex)" {
-       set foo_label_addr $expect_out(1,string)
+       set bar_label_addr $expect_out(1,string)
        pass $gdb_test_name
     }
 }
 
-if { $foo_label_addr == "" } {
+if { $bar_label_addr == "" } {
     return
 }
 
@@ -115,4 +115,4 @@ gdb_test "print &foo_end == &bar_label" " = 1"
 # Check that the breakpoint is set at the expected address.  Regression test
 # for PR30369.
 
-gdb_assert { $break_addr == $foo_label_addr }
+gdb_assert { $break_addr < $bar_label_addr }