[PATCH] linux-record: Squash cases with identical handling

[Andreas Arnez <arnez at linux dot vnet dot ibm dot com>]

While discussing a fix for a bad fall-through in linux-record.c, it was
pointed out that the cases for gdb_sys_pipe2 and gdb_sys_pipe can be
squashed into one.  Thus I promised a minor cleanup for cases with
identical handling:

  https://sourceware.org/ml/gdb-patches/2016-03/msg00310.html

I've had this in my pipe for some time, so here it is.  There should not
be any functional change.

-- >8 --
Subject: [PATCH] linux-record: Squash cases with identical handling

In record_linux_system_call there are some cases with identical
handling.  These are merged together to reduce code duplication.

gdb/ChangeLog:

	* linux-record.c (record_linux_system_call): Merge handling for
	readlink/recv/read and pipe/pipe2.  Also move handling for ppoll
	before the case for poll and use fall-through logic.
---
 gdb/linux-record.c | 40 ++++++++--------------------------------
 1 file changed, 8 insertions(+), 32 deletions(-)

diff --git a/gdb/linux-record.c b/gdb/linux-record.c
index fda7ada..6b84a18 100644
--- a/gdb/linux-record.c
+++ b/gdb/linux-record.c
@@ -264,6 +264,8 @@ record_linux_system_call (enum gdb_syscall syscall,
       break;
 
     case gdb_sys_read:
+    case gdb_sys_readlink:
+    case gdb_sys_recv:
       regcache_raw_read_unsigned (regcache, tdep->arg3, &tmpulongest);
       if (record_mem_at_reg (regcache, tdep->arg2, (int) tmpulongest))
 	return -1;
@@ -348,6 +350,7 @@ record_linux_system_call (enum gdb_syscall syscall,
       break;
 
     case gdb_sys_pipe:
+    case gdb_sys_pipe2:
       if (record_mem_at_reg (regcache, tdep->arg1, tdep->size_int * 2))
 	return -1;
       break;
@@ -645,12 +648,6 @@ record_linux_system_call (enum gdb_syscall syscall,
     case gdb_sys_symlink:
       break;
 
-    case gdb_sys_readlink:
-      regcache_raw_read_unsigned (regcache, tdep->arg3, &tmpulongest);
-      if (record_mem_at_reg (regcache, tdep->arg2, (int) tmpulongest))
-	return -1;
-      break;
-
     case gdb_sys_uselib:
     case gdb_sys_swapon:
       break;
@@ -742,12 +739,6 @@ Do you want to stop the program?"),
       }
       break;
 
-    case gdb_sys_recv:
-      regcache_raw_read_unsigned (regcache, tdep->arg3, &tmpulongest);
-      if (record_mem_at_reg (regcache, tdep->arg2, (int) tmpulongest))
-	return -1;
-      break;
-
     case gdb_sys_recvmsg:
       regcache_raw_read_unsigned (regcache, tdep->arg2, &tmpulongest);
       if (record_linux_msghdr (regcache, tdep, tmpulongest))
@@ -1364,6 +1355,11 @@ Do you want to stop the program?"),
     case gdb_sys_ni_syscall167:
       break;
 
+    case gdb_sys_ppoll:
+      if (record_mem_at_reg (regcache, tdep->arg3, tdep->size_timespec))
+	return -1;
+      /* Fall through.  */
+
     case gdb_sys_poll:
       regcache_raw_read_unsigned (regcache, tdep->arg1, &tmpulongest);
       if (tmpulongest)
@@ -1959,21 +1955,6 @@ Do you want to stop the program?"),
 	return -1;
       break;
 
-    case gdb_sys_ppoll:
-      regcache_raw_read_unsigned (regcache, tdep->arg1, &tmpulongest);
-      if (tmpulongest)
-	{
-	  ULONGEST nfds;
-
-	  regcache_raw_read_unsigned (regcache, tdep->arg2, &nfds);
-	  if (record_full_arch_list_add_mem ((CORE_ADDR) tmpulongest,
-					     tdep->size_pollfd * nfds))
-	    return -1;
-	}
-      if (record_mem_at_reg (regcache, tdep->arg3, tdep->size_timespec))
-	return -1;
-      break;
-
     case gdb_sys_unshare:
     case gdb_sys_set_robust_list:
       break;
@@ -2035,11 +2016,6 @@ Do you want to stop the program?"),
     case gdb_sys_dup3:
       break;
 
-    case gdb_sys_pipe2:
-      if (record_mem_at_reg (regcache, tdep->arg1, tdep->size_int * 2))
-	return -1;
-      break;
-
     case gdb_sys_inotify_init1:
       break;
 
-- 
2.5.0