[PATCH][GAS][ARM]Fix "align directive causes MAP_DATA symbol to be lost"

[Renlin Li <renlin dot li at arm dot com>]

Hi all,

A MAP_DATA symbol emission is postponed until the code is in MAP_ARM or 
MAP_THUMB state.
When we have the following similar asm,

.text
.long 123  --> (1)
.align 4     --> (2)
    bx    lr

(1) MAP_DATA is ignored as the code is initially in MAP_UNDEFINED mode.

a .align(2) directive will trigger a frag initialization to setup the 
MAP_ARM/MAR_THUMB state and code mapping symbol. After that a new frag 
is created. And the MAP_DATA symbol for (1) is left forgotten silently.

This patch change the structure a little bit,  to correctly emit 
MAP_DATA mapping symbol.
Two test cases are also adjusted.

Gas regression tests Okay. arm-none-eabi target is checked Okay.
Okay to commit?

gas/ChangeLog:

2015-03-05  Renlin Li  <renlin.li@arm.com>

    * config/tc-arm.c (mapping_state): Remove first MAP_DATA emitting code.
    * config/tc-arm.c (mapping_state_2): Emit first MAP_DATA symbol here.

gas/testsuite/ChangeLog:

2015-03-05  Renlin Li  <renlin.li@arm.com>

    * gas/arm/dis-data.d: Adjust the desired output.
    * gas/arm/dis-data2.d: Ditto.

diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c
index b17ea6c..66f73e5 100644
--- a/gas/config/tc-arm.c
+++ b/gas/config/tc-arm.c
@@ -2632,13 +2632,12 @@ static void mapping_state_2 (enum mstate state, int max_chars);
 /* Set the mapping state to STATE.  Only call this when about to
    emit some STATE bytes to the file.  */
 
+#define TRANSITION(from, to) (mapstate == (from) && state == (to))
 void
 mapping_state (enum mstate state)
 {
   enum mstate mapstate = seg_info (now_seg)->tc_segment_info_data.mapstate;
 
-#define TRANSITION(from, to) (mapstate == (from) && state == (to))
-
   if (mapstate == state)
     /* The mapping symbol has already been emitted.
        There is nothing else to do.  */
@@ -2661,24 +2660,10 @@ mapping_state (enum mstate state)
     record_alignment (now_seg, state == MAP_ARM ? 2 : 1);
 
   if (TRANSITION (MAP_UNDEFINED, MAP_DATA))
-    /* This case will be evaluated later in the next else.  */
+    /* This case will be evaluated later.  */
     return;
-  else if (TRANSITION (MAP_UNDEFINED, MAP_ARM)
-	  || TRANSITION (MAP_UNDEFINED, MAP_THUMB))
-    {
-      /* Only add the symbol if the offset is > 0:
-	 if we're at the first frag, check it's size > 0;
-	 if we're not at the first frag, then for sure
-	    the offset is > 0.  */
-      struct frag * const frag_first = seg_info (now_seg)->frchainP->frch_root;
-      const int add_symbol = (frag_now != frag_first) || (frag_now_fix () > 0);
-
-      if (add_symbol)
-	make_mapping_symbol (MAP_DATA, (valueT) 0, frag_first);
-    }
 
   mapping_state_2 (state, 0);
-#undef TRANSITION
 }
 
 /* Same as mapping_state, but MAX_CHARS bytes have already been
@@ -2697,9 +2682,20 @@ mapping_state_2 (enum mstate state, int max_chars)
        There is nothing else to do.  */
     return;
 
+  if (TRANSITION (MAP_UNDEFINED, MAP_ARM)
+	  || TRANSITION (MAP_UNDEFINED, MAP_THUMB))
+    {
+      struct frag * const frag_first = seg_info (now_seg)->frchainP->frch_root;
+      const int add_symbol = (frag_now != frag_first) || (frag_now_fix () > 0);
+
+      if (add_symbol)
+	make_mapping_symbol (MAP_DATA, (valueT) 0, frag_first);
+    }
+
   seg_info (now_seg)->tc_segment_info_data.mapstate = state;
   make_mapping_symbol (state, (valueT) frag_now_fix () - max_chars, frag_now);
 }
+#undef TRANSITION
 #else
 #define mapping_state(x) ((void)0)
 #define mapping_state_2(x, y) ((void)0)
diff --git a/gas/testsuite/gas/arm/dis-data.d b/gas/testsuite/gas/arm/dis-data.d
index 40ca770..c389763 100644
--- a/gas/testsuite/gas/arm/dis-data.d
+++ b/gas/testsuite/gas/arm/dis-data.d
@@ -5,6 +5,6 @@
 .*: +file format .*arm.*
 
 Disassembly of section \.text:
-0x00000000 20010000 	andcs	r0, r1, r0
-0x00000004 000000f9 	strdeq	r0, \[r0\], -r9
-0x00000008 00004cd5 	ldrdeq	r4, \[r0\], -r5
+00000000 <.text> 20010000 	.word	0x20010000
+00000004 <.text\+0x4> 000000f9 	.word	0x000000f9
+00000008 <.text\+0x8> 00004cd5 	.word	0x00004cd5
diff --git a/gas/testsuite/gas/arm/dis-data2.d b/gas/testsuite/gas/arm/dis-data2.d
index ef7bb81..9c50654 100644
--- a/gas/testsuite/gas/arm/dis-data2.d
+++ b/gas/testsuite/gas/arm/dis-data2.d
@@ -5,6 +5,6 @@
 .*: +file format .*arm.*
 
 Disassembly of section \.text:
-00000000 <main> 20010000 	andcs	r0, r1, r0
-00000004 <main\+0x4> 000000f9 	strdeq	r0, \[r0\], -r9
-00000008 <main\+0x8> 00004cd5 	ldrdeq	r4, \[r0\], -r5
+00000000 <main> 20010000 	.word	0x20010000
+00000004 <main\+0x4> 000000f9 	.word	0x000000f9
+00000008 <main\+0x8> 00004cd5 	.word	0x00004cd5