[PATCH] Fix gdb.dwarf2/dw2-dir-file-name.exp test for MIPS architectures

[Kwok Cheung Yeung <kwok_yeung@mentor.com>]

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This patch fixes the failures that occur with the 
gdb.dwarf2/dw2-dir-file-name.exp test on 64-bit MIPS and compressed MIPS 
ISAs (i.e. MIPS16 and microMIPS).

The failures on 64-bit occur because the generated DWARF address 
information is always 32-bit, which causes the upper 32-bits of 
addresses to be truncated and causes breakpoints to be set on the wrong 
address if any of the upper 32-bits are non-zero. I suspect that other 
64-bit architectures get away with it because they place all their 
instructions at a VMA lower than 2^32 by default. This patch causes 
64-bit addresses to be generated if a 64-bit target is detected.

The failures on MIPS16 and microMIPS occur because the breakpoint 
address needs to have the LSB set to 1 (used to indicate that the code 
is compressed). However, the function name is interpreted as a data 
label, causing GDB to set breakpoints at even addresses. This is fixed 
by explicitly adding a '.insn' directive (see 
https://sourceware.org/binutils/docs/as/MIPS-insn.html) after the label 
on MIPS only.

Kwok

2014-08-14  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gdb/testsuite/
	* gdb.dwarf2/dw2-dir-file-name.exp (addr_len): New.
	(out_cu): Use addr_len for the size of addresses.
	(out_line): Likewise.  Size DW_LNE_set_address instruction
	according to addr_len.
	* gdb.dwarf2/dw2-dir-file-name.c (START_INSNS): New.
	(FUNC): Add START_INSNS to definition.

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diff --git a/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.c b/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.c
index 517df90..69aad30 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.c
+++ b/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.c
@@ -63,6 +63,12 @@ FUNC (compdir_absolute_ldir_absolute_file_relative_different)	\
 FUNC (compdir_absolute_ldir_absolute_file_absolute_same)	\
 FUNC (compdir_absolute_ldir_absolute_file_absolute_different)
 
+#ifdef __mips__
+#define START_INSNS asm (".insn\n");
+#else
+#define START_INSNS
+#endif
+
 /* Notes: (1) The '*_start' label below is needed because 'name' may
    point to a function descriptor instead of to the actual code.  (2)
    The '.balign' should specify the highest possible function
@@ -72,6 +78,7 @@ FUNC (compdir_absolute_ldir_absolute_file_absolute_different)
 #define FUNC(name)					\
   asm (".balign 8");					\
   asm (#name "_start: .globl " #name "_start\n");	\
+  START_INSNS						\
   static void						\
   name (void)						\
   {							\
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.exp b/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.exp
index 7f29581..6c92441 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-dir-file-name.exp
@@ -19,6 +19,13 @@ if {![dwarf2_support]} {
     return 0  
 }
 
+# Find length of addresses in bytes.
+if {[is_64_target]} {
+    set addr_len 8
+} else {
+    set addr_len 4
+}
+
 standard_testfile
 set asmsrcfile [standard_output_file ${testfile}asm.S]
 set asmobjfile [standard_output_file ${testfile}asm.o]
@@ -36,6 +43,7 @@ puts $f "/* DO NOT EDIT! GENERATED AUTOMATICALLY! */"
 
 proc out_cu { name cu_dir cu_name line_dir line_name } {
     global f
+    global addr_len
 
     puts -nonewline $f "\
 .L${name}_begin:
@@ -43,7 +51,7 @@ proc out_cu { name cu_dir cu_name line_dir line_name } {
 .L${name}_start:
 	.2byte	2				/* DWARF Version */
 	.4byte	.Labbrev1_begin			/* Offset into abbrev section */
-	.byte	4				/* Pointer size */
+	.byte	${addr_len}				/* Pointer size */
 "
     if { $cu_dir != "" } {
 	puts $f "  .uleb128 ABBREV_COMP_DIR_NAME /* Abbrev: DW_TAG_compile_unit */"
@@ -54,8 +62,8 @@ proc out_cu { name cu_dir cu_name line_dir line_name } {
 	.ascii	\"GNU C\\0\"			/* DW_AT_producer */
 	.byte	2				/* DW_AT_language (DW_LANG_C) */
 	.4byte	.Lline_${name}_begin		/* DW_AT_stmt_list */
-	.4byte	${name}_start			/* DW_AT_low_pc */
-	.4byte	${name}_end			/* DW_AT_high_pc */
+	.${addr_len}byte	${name}_start			/* DW_AT_low_pc */
+	.${addr_len}byte	${name}_end			/* DW_AT_high_pc */
 "
     if { $cu_dir != "" } {
 	puts $f "  .ascii $cu_dir /* DW_AT_comp_dir */"
@@ -65,8 +73,8 @@ proc out_cu { name cu_dir cu_name line_dir line_name } {
 
 	.uleb128	3			/* Abbrev: DW_TAG_subprogram */
 	.asciz		\"${name}\"		/* DW_AT_name */
-	.4byte		${name}_start		/* DW_AT_low_pc */
-	.4byte		${name}_end		/* DW_AT_high_pc */
+	.${addr_len}byte		${name}_start		/* DW_AT_low_pc */
+	.${addr_len}byte		${name}_end		/* DW_AT_high_pc */
 
 	.byte		0			/* End of children of CU */
 .L${name}_end:
@@ -75,6 +83,7 @@ proc out_cu { name cu_dir cu_name line_dir line_name } {
 
 proc out_line { name cu_dir cu_name line_dir line_name } {
     global f
+    global addr_len
 
     puts -nonewline $f "\
 .Lline_${name}_begin:
@@ -120,16 +129,16 @@ proc out_line { name cu_dir cu_name line_dir line_name } {
 	.byte		3	/* DW_LNS_advance_line */
 	.sleb128	998	/* ... to 999 */
 	.byte		0	/* DW_LNE_set_address */
-	.uleb128	5
+	.uleb128	${addr_len}+1
 	.byte		2
-	.4byte		${name}_start
+	.${addr_len}byte		${name}_start
 	.byte		1	/* DW_LNS_copy */
 	.byte		3	/* DW_LNS_advance_line */
 	.sleb128	1	/* ... to 1000 */
 	.byte		0	/* DW_LNE_set_address */
-	.uleb128	5
+	.uleb128	${addr_len}+1
 	.byte		2
-	.4byte		${name}_end
+	.${addr_len}byte		${name}_end
 	.byte		1	/* DW_LNS_copy */
 	.byte		0	/* DW_LNE_end_of_sequence */
 	.uleb128	1