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

Kwok Cheung Yeung
2014-10-11T21:01:15Z

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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