The function dwarf_formsdata is used for decoding signed values, but
except for the variable-length DW_FORM_sdata, it uses unsigned
primitives to decode the value. This is not a problem for 64-bit values,
but the smaller values come decoded wrong. Fix by changing to signed
primitives for decoding the fixed-length forms.
Add a test case that uses dwarf_aggregate_size to determine an array
size whose lower bound is -1, encoded using DW_FORM_data1, and upper
bound 255 with DW_FORM_data2. When the -1 is decoded wrongly, it comes
back as 255, and the array size is 1. The correct array size should be
257.
Signed-off-by: Petr Machata
---
libdw/ChangeLog | 7
libdw/dwarf_formsdata.c | 8 ++---
tests/run-aggregate-size.sh | 8 -
tests/testfile-sizes4.o.bz2 | Bin 0 -> 387 bytes
tests/testfile-sizes4.s | 77
5 files changed, 95 insertions(+), 5 deletions(-)
create mode 100644 tests/testfile-sizes4.o.bz2
create mode 100644 tests/testfile-sizes4.s
Regarding testfile-sizes4.s, that's a product of a TCL script written using
dwarf.exp from GDB. I can post it as well (actually would prefer it like
that),but I think you bounced it before already (I found a TCL script foranother
test case from way back in my elfutils directory. I seem to recall you
didn'tlike this approach for whatever reason.)
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 7cfc7825..479dd42b 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,10 @@
+2018-01-14 Petr Machata
+
+ * dwarf_formsdata.c (dwarf_formsdata):
+ : Cast to signed char.
+ : Use read_*sbyte_unaligned instead of
+ read_*ubyte_unaligned.
+
2017-12-26 Mark Wielaard
* libdwP.h (struct Dwarf_Abbrev): Pack struct. Remove attrcnt,
diff --git a/libdw/dwarf_formsdata.c b/libdw/dwarf_formsdata.c
index e7deaee1..bc2b508d 100644
--- a/libdw/dwarf_formsdata.c
+++ b/libdw/dwarf_formsdata.c
@@ -53,25 +53,25 @@ dwarf_formsdata (Dwarf_Attribute *attr, Dwarf_Sword
*return_sval)
__libdw_seterrno (DWARF_E_INVALID_DWARF);
return -1;
}
- *return_sval = *attr->valp;
+ *return_sval = (signed char) *attr->valp;
break;
case DW_FORM_data2:
if (datap + 2 > endp)
goto invalid;
- *return_sval = read_2ubyte_unaligned (attr->cu->dbg, attr->valp);
+ *return_sval = read_2sbyte_unaligned (attr->cu->dbg, attr->valp);
break;
case DW_FORM_data4:
if (datap + 4 > endp)
goto invalid;
- *return_sval = read_4ubyte_unaligned (attr->cu->dbg, attr->valp);
+ *return_sval = read_4sbyte_unaligned (attr->cu->dbg, attr->valp);
break;
case DW_FORM_data8:
if (datap + 8 > endp)
goto invalid;
- *return_sval = read_8ubyte_unaligned (attr->cu->dbg, attr->valp);
+ *return_sval = read_8sbyte_unaligned (attr->cu->dbg, attr->valp);
break;
case DW_FORM_sdata:
diff --git a/tests/run-aggregate-size.sh b/tests/run-aggregate-size.sh
index 6d8aa240..08d57bbf 100755
--- a/tests/run-aggregate-size.sh
+++ b/tests/run-aggregate-size.sh
@@ -63,7 +63,9 @@
#
# gcc -std=c99 -g -c -o testfile-sizes3.o sizes.c
-testfiles testfile-sizes1.o testfile-sizes2.o testfile-sizes3.o
+# The file testfile-size4.o is hand-crafted.
+
+testfiles testfile-sizes1.o testfile-sizes2.o testfile-sizes3.o
testfile-sizes4.o
testrun_compare ${abs_builddir}/aggregate_size -e testfile-sizes1.o <<\EOF
c size 1
@@ -104,4 +106,8 @@ f size 4
b size 4
EOF
+testrun_compare ${abs_builddir}/aggregate_size -e testfile-sizes4.o <<\EOF
+v size 257
+EOF
+
exit 0
diff --git a/tests/testfile-sizes4.o.bz2 b/tests/testfile-sizes4.o.bz2
new file mode 100644
index
..046e0a23429c166c659349f628c39170bbb4818f
GIT binary patch
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zn4E{qj4D#xi1vKslj!Or-mJ>1XagNuBz3(2vJWi57V$TVwSIoYVz!`!_C;
