[1/2] Catch exceptions thrown from gdbarch_skip_prologue

diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index 2ae3413..0402eba 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -985,6 +985,24 @@  default_print_insn (bfd_vma memaddr, disassemble_info *info)
   return (*disassemble_fn) (memaddr, info);
 }
 
+/* See arch-utils.h.  */
+
+CORE_ADDR
+gdbarch_skip_prologue_noexcept (gdbarch *gdbarch, CORE_ADDR pc) noexcept
+{
+  CORE_ADDR new_pc = pc;
+
+  TRY
+    {
+      new_pc = gdbarch_skip_prologue (gdbarch, pc);
+    }
+  CATCH (ex, RETURN_MASK_ALL)
+    {}
+  END_CATCH
+
+  return new_pc;
+}
+
 /* -Wmissing-prototypes */
 extern initialize_file_ftype _initialize_gdbarch_utils;
 
diff --git a/gdb/arch-utils.h b/gdb/arch-utils.h
index 2aa9159..fa29086 100644
--- a/gdb/arch-utils.h
+++ b/gdb/arch-utils.h
@@ -268,4 +268,10 @@  extern void default_guess_tracepoint_registers (struct gdbarch *gdbarch,
 
 extern int default_print_insn (bfd_vma memaddr, disassemble_info *info);
 
+/* Wrapper to gdbarch_skip_prologue, but doesn't throw exception.  Catch
+   exception thrown from gdbarch_skip_prologue, and return PC.  */
+
+extern CORE_ADDR gdbarch_skip_prologue_noexcept (gdbarch *gdbarch,
+						 CORE_ADDR pc) noexcept;
+
 #endif
diff --git a/gdb/infrun.c b/gdb/infrun.c
index a68da6a..37ff015 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -66,6 +66,7 @@ 
 #include "common/enum-flags.h"
 #include "progspace-and-thread.h"
 #include "common/gdb_optional.h"
+#include "arch-utils.h"
 
 /* Prototypes for local functions */
 
@@ -7317,8 +7318,8 @@  handle_step_into_function (struct gdbarch *gdbarch,
 
   cust = find_pc_compunit_symtab (stop_pc);
   if (cust != NULL && compunit_language (cust) != language_asm)
-    ecs->stop_func_start = gdbarch_skip_prologue (gdbarch,
-						  ecs->stop_func_start);
+    ecs->stop_func_start
+      = gdbarch_skip_prologue_noexcept (gdbarch, ecs->stop_func_start);
 
   stop_func_sal = find_pc_line (ecs->stop_func_start, 0);
   /* Use the step_resume_break to step until the end of the prologue,
@@ -7396,8 +7397,8 @@  handle_step_into_function_backward (struct gdbarch *gdbarch,
 
   cust = find_pc_compunit_symtab (stop_pc);
   if (cust != NULL && compunit_language (cust) != language_asm)
-    ecs->stop_func_start = gdbarch_skip_prologue (gdbarch,
-						  ecs->stop_func_start);
+    ecs->stop_func_start
+      = gdbarch_skip_prologue_noexcept (gdbarch, ecs->stop_func_start);
 
   stop_func_sal = find_pc_line (stop_pc, 0);
 
diff --git a/gdb/symtab.c b/gdb/symtab.c
index d4e107a..ccf31cc 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -64,6 +64,7 @@ 
 #include "progspace-and-thread.h"
 #include "common/gdb_optional.h"
 #include "filename-seen-cache.h"
+#include "arch-utils.h"
 
 /* Forward declarations for local functions.  */
 
@@ -3627,7 +3628,7 @@  skip_prologue_sal (struct symtab_and_line *sal)
       if (gdbarch_skip_entrypoint_p (gdbarch))
         pc = gdbarch_skip_entrypoint (gdbarch, pc);
       if (skip)
-	pc = gdbarch_skip_prologue (gdbarch, pc);
+	pc = gdbarch_skip_prologue_noexcept (gdbarch, pc);
 
       /* For overlays, map pc back into its mapped VMA range.  */
       pc = overlay_mapped_address (pc, section);
diff --git a/gdb/testsuite/gdb.base/reread.exp b/gdb/testsuite/gdb.base/reread.exp
index cc0f577..4e611ce 100644
--- a/gdb/testsuite/gdb.base/reread.exp
+++ b/gdb/testsuite/gdb.base/reread.exp
@@ -15,111 +15,131 @@ 
 
 set prototypes 1
 
-# build the first test case
+# Build programs in PIE mode, to reproduce PR 21555.
+foreach_with_prefix opts {
+    { "" "" }
+    { "-fPIE" "ldflags=-pie" } } {
 
-set testfile1 "reread1"
-set srcfile1 ${testfile1}.c
-# Cygwin needs $EXEEXT.
-set binfile1 [standard_output_file ${testfile1}$EXEEXT]
-
-if  { [gdb_compile "${srcdir}/${subdir}/${srcfile1}" "${binfile1}" executable {debug nowarnings}] != "" } {
-    untested "failed to compile first testcase"
-    return -1
-}
-
-# build the second test case
-
-set testfile2 "reread2"
-set srcfile2 ${testfile2}.c
-set binfile2 [standard_output_file ${testfile2}$EXEEXT]
-
-if  { [gdb_compile "${srcdir}/${subdir}/${srcfile2}" "${binfile2}" executable {debug nowarnings}] != ""
-      && [gdb_compile "${srcdir}/${subdir}/${srcfile2}" "${binfile2}" executable {debug nowarnings additional_flags=-DNO_SECTIONS}] != ""} {
-    untested "failed to compile second testcase"
-    return -1
-}
-
-# Start with a fresh gdb.
-
-set testfile "reread"
-set binfile [standard_output_file ${testfile}$EXEEXT]
-
-gdb_start
-gdb_reinitialize_dir $srcdir/$subdir
-
-# Load the first executable.
-
-gdb_rename_execfile ${binfile1} ${binfile}
-gdb_load ${binfile}
-
-# Set a breakpoint at foo
-
-gdb_test "break foo" \
-    "Breakpoint.*at.* file .*$srcfile1, line 14.*" \
-    "breakpoint foo in first file"
-
-
-# Run, should see "Breakpoint 1, foo () at hello1.c:14"
-
-gdb_run_cmd
-gdb_test "" "Breakpoint.* foo .* at .*$srcfile1:14.*" "run to foo()"
-
-# Restore first executable to its original name, and move
-# second executable into its place.  Ensure that the new
-# executable is at least a second newer than the old.
-
-gdb_rename_execfile ${binfile} ${binfile1}
-gdb_rename_execfile ${binfile2} ${binfile}
-gdb_test "shell sleep 1" ".*" ""
-gdb_touch_execfile ${binfile}
-
-# Run a second time; GDB should detect that the executable has changed
-# and reset the breakpoints correctly.
-# Should see "Breakpoint 1, foo () at reread2.c:9"
-
-set test "run to foo() second time"
-if [is_remote target] {
-    unsupported $test
-} else {
-    gdb_run_cmd
-    gdb_test "" "Breakpoint.* foo .* at .*:9.*" $test
-}
-
-
-### Second pass: verify that GDB checks the executable file's
-### timestamp when the program is *restarted*, not just when it exits.
-
-if [is_remote target] {
-    unsupported "second pass: GDB should check for changes before running"
-} else {
-
-    # Put the older executable back in place.
-    gdb_rename_execfile ${binfile} ${binfile2}
-    gdb_rename_execfile ${binfile1} ${binfile}
-
-    # Restart GDB entirely.
-    clean_restart ${binfile}
-
-    # Set a breakpoint on foo and run to it.
-    gdb_test "break foo" \
-            "Breakpoint.*at.* file .*$srcfile1, line 14.*" \
-            "second pass: breakpoint foo in first file"
-    gdb_run_cmd
-    gdb_test "" "Breakpoint.* foo .* at .*$srcfile1:14.*" "second pass: run to foo()"
-
-    # This time, let the program run to completion.  If GDB checks the
-    # executable file's timestamp now, it won't notice any change.
-    gdb_continue_to_end "second pass"
-    
-    # Now move the newer executable into place, and re-run.  GDB
-    # should still notice that the executable file has changed,
-    # and still re-set the breakpoint appropriately.
-    gdb_rename_execfile ${binfile} ${binfile1}
-    gdb_rename_execfile ${binfile2} ${binfile}
-    gdb_run_cmd
-    gdb_test "" "Breakpoint.* foo .* at .*:9.*" "second pass: run to foo() second time"
-}
+	# build the first test case
 
+	set testfile1 "reread1"
+	set srcfile1 ${testfile1}.c
+	# Cygwin needs $EXEEXT.
+	set binfile1 [standard_output_file ${testfile1}$EXEEXT]
+
+	set testfile1_opt [list debug nowarnings \
+			       additional_flags=[lindex $opts 0] \
+			       [lindex $opts 1] ]
+	if  { [gdb_compile "${srcdir}/${subdir}/${srcfile1}" "${binfile1}" \
+		   executable ${testfile1_opt}] != "" } {
+	    untested "failed to compile first testcase"
+	    return -1
+	}
+
+	# build the second test case
+
+	set testfile2 "reread2"
+	set srcfile2 ${testfile2}.c
+	set binfile2 [standard_output_file ${testfile2}$EXEEXT]
+
+	set testfile2_opt1 [list debug nowarnings \
+				additional_flags=[lindex $opts 0] \
+				[lindex $opts 1]]
+	set testfile2_op2 [list debug nowarnings \
+			       "additional_flags=-DNO_SECTIONS [lindex $opts 0]" \
+			       [lindex $opts 1]]
+	if  { [gdb_compile "${srcdir}/${subdir}/${srcfile2}" "${binfile2}" \
+		   executable ${testfile2_opt1}] != ""
+	      && [gdb_compile "${srcdir}/${subdir}/${srcfile2}" "${binfile2}" \
+		      executable ${testfile2_opt2}] != ""} {
+	    untested "failed to compile second testcase"
+	    return -1
+	}
+
+	# Start with a fresh gdb.
+
+	set testfile "reread"
+	set binfile [standard_output_file ${testfile}$EXEEXT]
+
+	gdb_start
+	gdb_reinitialize_dir $srcdir/$subdir
+
+	# Load the first executable.
+
+	gdb_rename_execfile ${binfile1} ${binfile}
+	gdb_load ${binfile}
+
+	# Set a breakpoint at foo
+
+	gdb_test "break foo" \
+	    "Breakpoint.*at.* file .*$srcfile1, line 14.*" \
+	    "breakpoint foo in first file"
+
+
+	# Run, should see "Breakpoint 1, foo () at hello1.c:14"
+
+	gdb_run_cmd
+	gdb_test "" "Breakpoint.* foo .* at .*$srcfile1:14.*" "run to foo()"
+
+	# Restore first executable to its original name, and move
+	# second executable into its place.  Ensure that the new
+	# executable is at least a second newer than the old.
+
+	gdb_rename_execfile ${binfile} ${binfile1}
+	gdb_rename_execfile ${binfile2} ${binfile}
+	gdb_test "shell sleep 1" ".*" ""
+	gdb_touch_execfile ${binfile}
+
+	# Run a second time; GDB should detect that the executable has changed
+	# and reset the breakpoints correctly.
+	# Should see "Breakpoint 1, foo () at reread2.c:9"
+
+	set test "run to foo() second time"
+	if [is_remote target] {
+	    unsupported $test
+	} else {
+	    gdb_run_cmd
+	    gdb_test "" "Breakpoint.* foo .* at .*:9.*" $test
+	}
+
+
+	### Second pass: verify that GDB checks the executable file's
+	### timestamp when the program is *restarted*, not just when it exits.
+
+	if [is_remote target] {
+	    unsupported "second pass: GDB should check for changes before running"
+	} else {
+
+	    # Put the older executable back in place.
+	    gdb_rename_execfile ${binfile} ${binfile2}
+	    gdb_rename_execfile ${binfile1} ${binfile}
+
+	    # Restart GDB entirely.
+	    clean_restart ${binfile}
+
+	    # Set a breakpoint on foo and run to it.
+	    gdb_test "break foo" \
+		"Breakpoint.*at.* file .*$srcfile1, line 14.*" \
+		"second pass: breakpoint foo in first file"
+	    gdb_run_cmd
+	    gdb_test "" "Breakpoint.* foo .* at .*$srcfile1:14.*" \
+		"second pass: run to foo()"
+
+	    # This time, let the program run to completion.  If GDB checks the
+	    # executable file's timestamp now, it won't notice any change.
+	    gdb_continue_to_end "second pass"
+
+	    # Now move the newer executable into place, and re-run.  GDB
+	    # should still notice that the executable file has changed,
+	    # and still re-set the breakpoint appropriately.
+	    gdb_rename_execfile ${binfile} ${binfile1}
+	    gdb_rename_execfile ${binfile2} ${binfile}
+	    gdb_run_cmd
+	    gdb_test "" "Breakpoint.* foo .* at .*:9.*" \
+		"second pass: run to foo() second time"
+	}
+
+    }
 # End of tests.
 
 return 0