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authorRobert O'Callahan <robert@ocallahan.org>2015-07-08 10:53:36 +0100
committerPedro Alves <palves@redhat.com>2015-07-08 10:53:36 +0100
commitbcf5c1d96b3b5493041002eb2b6d27288d9d160a (patch)
treed7267257d9f989850cb58cf7cd06a8ed0d889b04
parente8643a4533a92e011dad97ea53c99d314c06513d (diff)
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PR18617 - Incorrect expression bytecode generated for narrowing conversions
The existing code preserves 'from' bits, which is incorrect. E.g. (gdb) maint agent-eval (char)255L Scope: 0x4008d6 Reg mask: 00 0 const16 255 3 ext 64 5 end 'ext 64' should be 'ext 8'; this bytecode evaluates to 255 instead of the correct result of -1. The fix is simple. I ran the entire test suite on x86-64 and there were no new test failures. gdb/ChangeLog: 2015-07-08 Robert O'Callahan <robert@ocallahan.org> PR exp/18617 * ax-gdb.c (gen_conversion): Extend to 'to' bits, not 'from'. gdb/testsuite/ChangeLog: 2015-07-08 Robert O'Callahan <robert@ocallahan.org> PR exp/18617 * gdb.trace/ax.exp: Add test.
-rw-r--r--gdb/ChangeLog5
-rw-r--r--gdb/ax-gdb.c2
-rw-r--r--gdb/testsuite/ChangeLog5
-rw-r--r--gdb/testsuite/gdb.trace/ax.exp2
4 files changed, 13 insertions, 1 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index de4ca2e..723ed2c 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2015-07-08 Robert O'Callahan <robert@ocallahan.org>
+
+ PR exp/18617
+ * ax-gdb.c (gen_conversion): Extend to 'to' bits, not 'from'.
+
2015-07-08 Markus Metzger <markus.t.metzger@intel.com>
* MAINTAINERS (Write After Approval): Add Markus T. Metzger.
diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 7a9d1e7..38dacac 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -885,7 +885,7 @@ gen_conversion (struct agent_expr *ax, struct type *from, struct type *to)
/* If we're converting to a narrower type, then we need to clear out
the upper bits. */
if (TYPE_LENGTH (to) < TYPE_LENGTH (from))
- gen_extend (ax, from);
+ gen_extend (ax, to);
/* If the two values have equal width, but different signednesses,
then we need to extend. */
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index c5386b2..285bf2c 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-07-08 Robert O'Callahan <robert@ocallahan.org>
+
+ PR exp/18617
+ * gdb.trace/ax.exp: Add test.
+
2015-07-07 Yao Qi <yao.qi@linaro.org>
* gdb.arch/aarch64-atomic-inst.exp: Check is_aarch64_target
diff --git a/gdb/testsuite/gdb.trace/ax.exp b/gdb/testsuite/gdb.trace/ax.exp
index e3d0479..d064475 100644
--- a/gdb/testsuite/gdb.trace/ax.exp
+++ b/gdb/testsuite/gdb.trace/ax.exp
@@ -80,6 +80,8 @@ gdb_test "maint agent &gdb_long_test == &gdb_short_test" "" "maint agent &gdb_lo
gdb_test "maint agent &gdb_long_test < &gdb_short_test" "" "maint agent &gdb_long_test < &gdb_short_test"
+gdb_test "maint agent (unsigned char)1L" ".*ext 8.*" "maint agent (unsigned char)1L"
+
# Now test eval version of agent expressions.
gdb_test "maint agent-eval 12" ".*const8 12.*end.*" "maint agent-eval 12"