Warnings Cleanup in Hotspot
Calvin Cheung
calvin.cheung at oracle.com
Wed May 15 14:37:23 PDT 2013
Jeremy,
We'll fix it in hs25 first and then backport it to hs24 if the fix is
applicable there.
Calvin
On 5/15/2013 2:14 PM, Jeremy Manson wrote:
> Thanks, Calvin. What does followup look like?
>
> Jeremy
>
>
> On Mon, May 13, 2013 at 9:59 AM, Calvin Cheung
> <calvin.cheung at oracle.com <mailto:calvin.cheung at oracle.com>> wrote:
>
> Hi Jeremy,
>
> I've created 8014431 (cleanup warnings indicated by the
> -Wunused-value compiler option on linux) to track this. It'll take
> a few hours for it to show up in the bugs.sun.com
> <http://bugs.sun.com>
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8014431
>
> Calvin
>
>
> On 5/10/2013 11:38 AM, Jeremy Manson wrote:
>
> Okay, I turned on -Wunused-value in the gcc makefile for
> Linux. I also ran this on a more recent build of HS (I was
> using something very, very old), and I got a few more warnings
> (including a couple that actually looked as if they would
> impact functionality). Thoughts on this?
>
> diff --git a/make/linux/makefiles/gcc.make
> b/make/linux/makefiles/gcc.make
> --- a/make/linux/makefiles/gcc.make
> +++ b/make/linux/makefiles/gcc.make
> @@ -126,7 +126,7 @@
> # Compiler warnings are treated as errors
> WARNINGS_ARE_ERRORS = -Werror
> -WARNING_FLAGS = -Wpointer-arith -Wsign-compare -Wundef
> -Wunused-function
> +WARNING_FLAGS = -Wpointer-arith -Wsign-compare -Wundef
> -Wunused-function -Wunused-value
> # Since GCC 4.3, -Wconversion has changed its meanings to
> warn these implicit
> # conversions which might affect the values. Only enable it
> in earlier versions.
> diff --git a/src/share/vm/c1/c1_IR.cpp b/src/share/vm/c1/c1_IR.cpp
> --- a/src/share/vm/c1/c1_IR.cpp
> +++ b/src/share/vm/c1/c1_IR.cpp
> @@ -506,7 +506,7 @@
> _loop_map(0, 0), // initialized later with correct
> size
> _compilation(c)
> {
> - TRACE_LINEAR_SCAN(2, "***** computing linear-scan block
> order");
> + TRACE_LINEAR_SCAN(2, tty->print_cr("***** computing
> linear-scan block order"));
> init_visited();
> count_edges(start_block, NULL);
> @@ -683,7 +683,7 @@
> }
> void ComputeLinearScanOrder::assign_loop_depth(BlockBegin*
> start_block) {
> - TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight");
> + TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing
> loop-depth and weight"));
> init_visited();
> assert(_work_list.is_empty(), "work list must be empty
> before processing");
> @@ -868,7 +868,7 @@
> }
> void ComputeLinearScanOrder::compute_order(BlockBegin*
> start_block) {
> - TRACE_LINEAR_SCAN(3, "----- computing final block order");
> + TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing final
> block order"));
> // the start block is always the first block in the linear
> scan order
> _linear_scan_order = new BlockList(_num_blocks);
> diff --git a/src/share/vm/code/nmethod.cpp
> b/src/share/vm/code/nmethod.cpp
> --- a/src/share/vm/code/nmethod.cpp
> +++ b/src/share/vm/code/nmethod.cpp
> @@ -2602,7 +2602,8 @@
> relocation_begin()-1+ip[1]);
> for (; ip < index_end; ip++)
> tty->print_cr(" (%d ?)", ip[0]);
> - tty->print_cr(" @" INTPTR_FORMAT ":
> index_size=%d", ip, *ip++);
> + tty->print_cr(" @" INTPTR_FORMAT ":
> index_size=%d", ip, *ip);
> + ip++;
> tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
> }
> }
> diff --git a/src/share/vm/memory/cardTableModRefBS.cpp
> b/src/share/vm/memory/cardTableModRefBS.cpp
> --- a/src/share/vm/memory/cardTableModRefBS.cpp
> +++ b/src/share/vm/memory/cardTableModRefBS.cpp
> @@ -395,7 +395,7 @@
> }
> // Touch the last card of the covered region to show that it
> // is committed (or SEGV).
> - debug_only(*byte_for(_covered[ind].last());)
> + debug_only((void) (*byte_for(_covered[ind].last()));)
> debug_only(verify_guard();)
> }
> diff --git a/src/share/vm/memory/universe.cpp
> b/src/share/vm/memory/universe.cpp
> --- a/src/share/vm/memory/universe.cpp
> +++ b/src/share/vm/memory/universe.cpp
> @@ -532,7 +532,9 @@
> if (vt) vt->initialize_vtable(false, CHECK);
> if (ko->oop_is_instance()) {
> InstanceKlass* ik = (InstanceKlass*)ko;
> - for (KlassHandle s_h(THREAD, ik->subklass()); s_h() !=
> NULL; s_h = (THREAD, s_h()->next_sibling())) {
> + for (KlassHandle s_h(THREAD, ik->subklass());
> + s_h() != NULL;
> + s_h = KlassHandle(THREAD, s_h()->next_sibling())) {
> reinitialize_vtable_of(s_h, CHECK);
> }
> }
> diff --git a/src/share/vm/runtime/sharedRuntime.cpp
> b/src/share/vm/runtime/sharedRuntime.cpp
> --- a/src/share/vm/runtime/sharedRuntime.cpp
> +++ b/src/share/vm/runtime/sharedRuntime.cpp
> @@ -2733,7 +2733,7 @@
> // ResourceObject, so do not put any ResourceMarks in here.
> char *s = sig->as_C_string();
> int len = (int)strlen(s);
> - *s++; len--; // Skip opening paren
> + s++; len--; // Skip opening paren
> char *t = s+len;
> while( *(--t) != ')' ) ; // Find close paren
> diff --git a/src/share/vm/services/diagnosticArgument.cpp
> b/src/share/vm/services/diagnosticArgument.cpp
> --- a/src/share/vm/services/diagnosticArgument.cpp
> +++ b/src/share/vm/services/diagnosticArgument.cpp
> @@ -232,7 +232,7 @@
> } else {
> _value._time = 0;
> _value._nanotime = 0;
> - strcmp(_value._unit, "ns");
> + strcpy(_value._unit, "ns");
> }
> }
> diff --git a/src/share/vm/utilities/taskqueue.hpp
> b/src/share/vm/utilities/taskqueue.hpp
> --- a/src/share/vm/utilities/taskqueue.hpp
> +++ b/src/share/vm/utilities/taskqueue.hpp
> @@ -340,8 +340,12 @@
> if (dirty_n_elems == N - 1) {
> // Actually means 0, so do the push.
> uint localBot = _bottom;
> - // g++ complains if the volatile result of the assignment
> is unused.
> - const_cast<E&>(_elems[localBot] = t);
> + // g++ complains if the volatile result of the assignment is
> + // unused, so we cast the volatile away. We cannot cast
> directly
> + // to void, because gcc treats that as not using the
> result of the
> + // assignment. However, casting to E& means that we
> trigger an
> + // unused-value warning. So, we cast the E& to void.
> + (void) const_cast<E&>(_elems[localBot] = t);
> OrderAccess::release_store(&_bottom,
> increment_index(localBot));
> TASKQUEUE_STATS_ONLY(stats.record_push());
> return true;
> @@ -397,7 +401,12 @@
> return false;
> }
> - const_cast<E&>(t = _elems[oldAge.top()]);
> + // g++ complains if the volatile result of the assignment is
> + // unused, so we cast the volatile away. We cannot cast
> directly
> + // to void, because gcc treats that as not using the result
> of the
> + // assignment. However, casting to E& means that we trigger an
> + // unused-value warning. So, we cast the E& to void.
> + (void) const_cast<E&>(t = _elems[oldAge.top()]);
> Age newAge(oldAge);
> newAge.increment();
> Age resAge = _age.cmpxchg(newAge, oldAge);
> @@ -640,8 +649,12 @@
> uint dirty_n_elems = dirty_size(localBot, top);
> assert(dirty_n_elems < N, "n_elems out of range.");
> if (dirty_n_elems < max_elems()) {
> - // g++ complains if the volatile result of the assignment
> is unused.
> - const_cast<E&>(_elems[localBot] = t);
> + // g++ complains if the volatile result of the assignment is
> + // unused, so we cast the volatile away. We cannot cast
> directly
> + // to void, because gcc treats that as not using the
> result of the
> + // assignment. However, casting to E& means that we
> trigger an
> + // unused-value warning. So, we cast the E& to void.
> + (void) const_cast<E&>(_elems[localBot] = t);
> OrderAccess::release_store(&_bottom,
> increment_index(localBot));
> TASKQUEUE_STATS_ONLY(stats.record_push());
> return true;
> @@ -665,7 +678,12 @@
> // This is necessary to prevent any read below from being
> reordered
> // before the store just above.
> OrderAccess::fence();
> - const_cast<E&>(t = _elems[localBot]);
> + // g++ complains if the volatile result of the assignment is
> + // unused, so we cast the volatile away. We cannot cast
> directly
> + // to void, because gcc treats that as not using the result
> of the
> + // assignment. However, casting to E& means that we trigger an
> + // unused-value warning. So, we cast the E& to void.
> + (void) const_cast<E&>(t = _elems[localBot]);
> // This is a second read of "age"; the "size()" above is
> the first.
> // If there's still at least one element in the queue,
> based on the
> // "_bottom" and "age" we've read, then there can be no
> interference with
>
>
>
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