gas/

	* config/tc-mips.c (append_insn): Make sure DWARF-2 location
	information is properly adjusted for branches that get swapped.

	gas/testsuite/
	* gas/mips/loc-swap.d: New test case for DWARF-2 location with
	branch swapping.
	* gas/mips/loc-swap-dis.d: Likewise.
	* gas/mips/mips16@loc-swap.d: Likewise, MIPS16 version.
	* gas/mips/mips16@loc-swap-dis.d: Likewise.
	* gas/mips/loc-swap.s: Source for the new tests.
	* gas/mips/mips.exp: Run the new tests.

8 files changed, 224 insertions, 4 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 2fe405c..8bc4f50 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,8 @@
+2011-07-04  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	* config/tc-mips.c (append_insn): Make sure DWARF-2 location
+	information is properly adjusted for branches that get swapped.
+
 2011-07-03  Samuel Thibault  <samuel.thibault@gnu.org>
 	    Thomas Schwinge  <thomas@schwinge.name>
 
diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index cdcebf1..2b3e4dc 100644
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -3454,10 +3454,20 @@ append_insn (struct mips_cl_insn *ip, expressionS *address_expr,
 #ifdef OBJ_ELF
   /* The value passed to dwarf2_emit_insn is the distance between
      the beginning of the current instruction and the address that
-     should be recorded in the debug tables.  For MIPS16 debug info
-     we want to use ISA-encoded addresses, so we pass -1 for an
-     address higher by one than the current.  */
-  dwarf2_emit_insn (mips_opts.mips16 ? -1 : 0);
+     should be recorded in the debug tables.  This is normally the
+     current address.
+
+     For MIPS16 debug info we want to use ISA-encoded addresses,
+     so we use -1 for an address higher by one than the current one.
+
+     If the instruction produced is a branch that we will swap with
+     the preceding instruction, then we add the displacement by which
+     the branch will be moved backwards.  This is more appropriate
+     and for MIPS16 code also prevents a debugger from placing a
+     breakpoint in the middle of the branch (and corrupting code if
+     software breakpoints are used).  */
+  dwarf2_emit_insn ((mips_opts.mips16 ? -1 : 0)
+		    + (method == APPEND_SWAP ? insn_length (history) : 0));
 #endif
 
   if (address_expr
diff --git a/gas/testsuite/ChangeLog b/gas/testsuite/ChangeLog
index 0b24323..e2ac6b8 100644
--- a/gas/testsuite/ChangeLog
+++ b/gas/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2011-07-04  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	* gas/mips/loc-swap.d: New test case for DWARF-2 location with
+	branch swapping.
+	* gas/mips/loc-swap-dis.d: Likewise.
+	* gas/mips/mips16@loc-swap.d: Likewise, MIPS16 version.
+	* gas/mips/mips16@loc-swap-dis.d: Likewise.
+	* gas/mips/loc-swap.s: Source for the new tests.
+	* gas/mips/mips.exp: Run the new tests.
+
 2011-06-30  H.J. Lu  <hongjiu.lu@intel.com>
 
 	AVX Programming Reference (June, 2011)
diff --git a/gas/testsuite/gas/mips/loc-swap-dis.d b/gas/testsuite/gas/mips/loc-swap-dis.d
new file mode 100644
index 0000000..c4601b9
--- /dev/null
+++ b/gas/testsuite/gas/mips/loc-swap-dis.d
@@ -0,0 +1,34 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS DWARF-2 location information with branch swapping disassembly
+#as: -32
+#source: loc-swap.s
+
+# Check branch swapping with DWARF-2 location information.
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+[0-9a-f]+ <[^>]*> 02002021 	move	a0,s0
+[0-9a-f]+ <[^>]*> 00800008 	jr	a0
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 00800008 	jr	a0
+[0-9a-f]+ <[^>]*> 0200f821 	move	ra,s0
+[0-9a-f]+ <[^>]*> 03e00008 	jr	ra
+[0-9a-f]+ <[^>]*> 02002021 	move	a0,s0
+[0-9a-f]+ <[^>]*> 0200f821 	move	ra,s0
+[0-9a-f]+ <[^>]*> 03e00008 	jr	ra
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 02002021 	move	a0,s0
+[0-9a-f]+ <[^>]*> 0080f809 	jalr	a0
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 0200f821 	move	ra,s0
+[0-9a-f]+ <[^>]*> 0080f809 	jalr	a0
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 0c000000 	jal	0+0000 <foo>
+[ 	]*[0-9a-f]+: R_MIPS_26	bar
+[0-9a-f]+ <[^>]*> 02002021 	move	a0,s0
+[0-9a-f]+ <[^>]*> 0200f821 	move	ra,s0
+[0-9a-f]+ <[^>]*> 0c000000 	jal	0+0000 <foo>
+[ 	]*[0-9a-f]+: R_MIPS_26	bar
+[0-9a-f]+ <[^>]*> 00000000 	nop
+	\.\.\.
diff --git a/gas/testsuite/gas/mips/loc-swap.d b/gas/testsuite/gas/mips/loc-swap.d
new file mode 100644
index 0000000..36fc814
--- /dev/null
+++ b/gas/testsuite/gas/mips/loc-swap.d
@@ -0,0 +1,61 @@
+#PROG: readelf
+#readelf: -wl
+#name: MIPS DWARF-2 location information with branch swapping
+#as: -32
+#source: loc-swap.s
+
+# Verify that DWARF-2 location information for instructions reordered
+# into a branch delay slot is updated to point to the branch instead.
+
+Raw dump of debug contents of section \.debug_line:
+
+  Offset:                      0x0
+  Length:                      67
+  DWARF Version:               2
+  Prologue Length:             33
+  Minimum Instruction Length:  1
+  Initial value of 'is_stmt':  1
+  Line Base:                   -5
+  Line Range:                  14
+  Opcode Base:                 13
+
+ Opcodes:
+  Opcode 1 has 0 args
+  Opcode 2 has 1 args
+  Opcode 3 has 1 args
+  Opcode 4 has 1 args
+  Opcode 5 has 1 args
+  Opcode 6 has 0 args
+  Opcode 7 has 0 args
+  Opcode 8 has 0 args
+  Opcode 9 has 1 args
+  Opcode 10 has 0 args
+  Opcode 11 has 0 args
+  Opcode 12 has 1 args
+
+ The Directory Table is empty\.
+
+ The File Name Table:
+  Entry	Dir	Time	Size	Name
+  1	0	0	0	loc-swap\.s
+
+ Line Number Statements:
+  Extended opcode 2: set Address to 0x0
+  Special opcode 11: advance Address by 0 to 0x0 and Line by 6 to 7
+  Special opcode 63: advance Address by 4 to 0x4 and Line by 2 to 9
+  Special opcode 120: advance Address by 8 to 0xc and Line by 3 to 12
+  Special opcode 7: advance Address by 0 to 0xc and Line by 2 to 14
+  Special opcode 120: advance Address by 8 to 0x14 and Line by 3 to 17
+  Special opcode 7: advance Address by 0 to 0x14 and Line by 2 to 19
+  Special opcode 120: advance Address by 8 to 0x1c and Line by 3 to 22
+  Special opcode 63: advance Address by 4 to 0x20 and Line by 2 to 24
+  Special opcode 120: advance Address by 8 to 0x28 and Line by 3 to 27
+  Special opcode 63: advance Address by 4 to 0x2c and Line by 2 to 29
+  Special opcode 120: advance Address by 8 to 0x34 and Line by 3 to 32
+  Special opcode 63: advance Address by 4 to 0x38 and Line by 2 to 34
+  Special opcode 120: advance Address by 8 to 0x40 and Line by 3 to 37
+  Special opcode 7: advance Address by 0 to 0x40 and Line by 2 to 39
+  Special opcode 120: advance Address by 8 to 0x48 and Line by 3 to 42
+  Special opcode 63: advance Address by 4 to 0x4c and Line by 2 to 44
+  Advance PC by 24 to 0x64
+  Extended opcode 1: End of Sequence
diff --git a/gas/testsuite/gas/mips/mips.exp b/gas/testsuite/gas/mips/mips.exp
index e31dbad..dd0bb64 100644
--- a/gas/testsuite/gas/mips/mips.exp
+++ b/gas/testsuite/gas/mips/mips.exp
@@ -854,6 +854,10 @@ if { [istarget mips*-*-vxworks*] } {
 					[mips_arch_list_matching mips1]
 	run_dump_test_arches "branch-misc-4-64" \
 					[mips_arch_list_matching mips3]
+
+	run_dump_test_arches "loc-swap"	[mips_arch_list_all]
+	run_dump_test_arches "loc-swap-dis" \
+					[mips_arch_list_all]
     }
 
     if $has_newabi {
diff --git a/gas/testsuite/gas/mips/mips16@loc-swap-dis.d b/gas/testsuite/gas/mips/mips16@loc-swap-dis.d
new file mode 100644
index 0000000..fd698ea
--- /dev/null
+++ b/gas/testsuite/gas/mips/mips16@loc-swap-dis.d
@@ -0,0 +1,35 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS DWARF-2 location information with branch swapping disassembly
+#as: -32
+#source: loc-swap.s
+
+# Check branch swapping with DWARF-2 location information (MIPS16).
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+[0-9a-f]+ <[^>]*> 6790      	move	a0,s0
+[0-9a-f]+ <[^>]*> ec00      	jr	a0
+[0-9a-f]+ <[^>]*> 6500      	nop
+[0-9a-f]+ <[^>]*> ec00      	jr	a0
+[0-9a-f]+ <[^>]*> 65f8      	move	ra,s0
+[0-9a-f]+ <[^>]*> e820      	jr	ra
+[0-9a-f]+ <[^>]*> 6790      	move	a0,s0
+[0-9a-f]+ <[^>]*> 65f8      	move	ra,s0
+[0-9a-f]+ <[^>]*> e820      	jr	ra
+[0-9a-f]+ <[^>]*> 6500      	nop
+[0-9a-f]+ <[^>]*> 6790      	move	a0,s0
+[0-9a-f]+ <[^>]*> ec40      	jalr	a0
+[0-9a-f]+ <[^>]*> 6500      	nop
+[0-9a-f]+ <[^>]*> 65f8      	move	ra,s0
+[0-9a-f]+ <[^>]*> ec40      	jalr	a0
+[0-9a-f]+ <[^>]*> 6500      	nop
+[0-9a-f]+ <[^>]*> 1800 0000 	jal	0+0000 <foo>
+[ 	]*[0-9a-f]+: R_MIPS16_26	bar
+[0-9a-f]+ <[^>]*> 6790      	move	a0,s0
+[0-9a-f]+ <[^>]*> 65f8      	move	ra,s0
+[0-9a-f]+ <[^>]*> 1800 0000 	jal	0+0000 <foo>
+[ 	]*[0-9a-f]+: R_MIPS16_26	bar
+[0-9a-f]+ <[^>]*> 6500      	nop
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
diff --git a/gas/testsuite/gas/mips/mips16@loc-swap.d b/gas/testsuite/gas/mips/mips16@loc-swap.d
new file mode 100644
index 0000000..fdae485
--- /dev/null
+++ b/gas/testsuite/gas/mips/mips16@loc-swap.d
@@ -0,0 +1,61 @@
+#PROG: readelf
+#readelf: -wl
+#name: MIPS DWARF-2 location information with branch swapping
+#as: -32
+#source: loc-swap.s
+
+# Verify that DWARF-2 location information for instructions reordered
+# into a branch delay slot is updated to point to the branch instead.
+
+Raw dump of debug contents of section \.debug_line:
+
+  Offset:                      0x0
+  Length:                      67
+  DWARF Version:               2
+  Prologue Length:             33
+  Minimum Instruction Length:  1
+  Initial value of 'is_stmt':  1
+  Line Base:                   -5
+  Line Range:                  14
+  Opcode Base:                 13
+
+ Opcodes:
+  Opcode 1 has 0 args
+  Opcode 2 has 1 args
+  Opcode 3 has 1 args
+  Opcode 4 has 1 args
+  Opcode 5 has 1 args
+  Opcode 6 has 0 args
+  Opcode 7 has 0 args
+  Opcode 8 has 0 args
+  Opcode 9 has 1 args
+  Opcode 10 has 0 args
+  Opcode 11 has 0 args
+  Opcode 12 has 1 args
+
+ The Directory Table is empty\.
+
+ The File Name Table:
+  Entry	Dir	Time	Size	Name
+  1	0	0	0	loc-swap\.s
+
+ Line Number Statements:
+  Extended opcode 2: set Address to 0x1
+  Special opcode 11: advance Address by 0 to 0x1 and Line by 6 to 7
+  Special opcode 35: advance Address by 2 to 0x3 and Line by 2 to 9
+  Special opcode 64: advance Address by 4 to 0x7 and Line by 3 to 12
+  Special opcode 7: advance Address by 0 to 0x7 and Line by 2 to 14
+  Special opcode 64: advance Address by 4 to 0xb and Line by 3 to 17
+  Special opcode 7: advance Address by 0 to 0xb and Line by 2 to 19
+  Special opcode 64: advance Address by 4 to 0xf and Line by 3 to 22
+  Special opcode 35: advance Address by 2 to 0x11 and Line by 2 to 24
+  Special opcode 64: advance Address by 4 to 0x15 and Line by 3 to 27
+  Special opcode 35: advance Address by 2 to 0x17 and Line by 2 to 29
+  Special opcode 64: advance Address by 4 to 0x1b and Line by 3 to 32
+  Special opcode 35: advance Address by 2 to 0x1d and Line by 2 to 34
+  Special opcode 64: advance Address by 4 to 0x21 and Line by 3 to 37
+  Special opcode 7: advance Address by 0 to 0x21 and Line by 2 to 39
+  Special opcode 92: advance Address by 6 to 0x27 and Line by 3 to 42
+  Special opcode 35: advance Address by 2 to 0x29 and Line by 2 to 44
+  Advance PC by 23 to 0x40
+  Extended opcode 1: End of Sequence