diff options
| author | Rekai Gonzalez-Alberquilla <rekai.gonzalezalberquilla@arm.com> | 2017-02-06 11:10:06 +0000 |
|---|---|---|
| committer | Giacomo Gabrielli <giacomo.gabrielli@arm.com> | 2018-11-16 10:39:03 +0000 |
| commit | 0c50a0b4fe3956f9d2e08e75d47c9cbd79bf0268 (patch) | |
| tree | 7679abe2343e0504c93eb73d09635d546a211455 /src/cpu/o3/rename_impl.hh | |
| parent | 338a173e822298bd22741342a7b24352450afdd1 (diff) | |
| download | gem5-0c50a0b4fe3956f9d2e08e75d47c9cbd79bf0268.tar.xz | |
cpu: Fix the usage of const DynInstPtr
Summary: Usage of const DynInstPtr& when possible and introduction of
move operators to RefCountingPtr.
In many places, scoped references to dynamic instructions do a copy of
the DynInstPtr when a reference would do. This is detrimental to
performance. On top of that, in case there is a need for reference
tracking for debugging, the redundant copies make the process much more
painful than it already is.
Also, from the theoretical point of view, a function/method that
defines a convenience name to access an instruction should not be
considered an owner of the data, i.e., doing a copy and not a reference
is not justified.
On a related topic, C++11 introduces move semantics, and those are
useful when, for example, there is a class modelling a HW structure that
contains a list, and has a getHeadOfList function, to prevent doing a
copy to an internal variable -> update pointer, remove from the list ->
update pointer, return value making a copy to the assined variable ->
update pointer, destroy the returned value -> update pointer.
Change-Id: I3bb46c20ef23b6873b469fd22befb251ac44d2f6
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13105
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Diffstat (limited to 'src/cpu/o3/rename_impl.hh')
| -rw-r--r-- | src/cpu/o3/rename_impl.hh | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/src/cpu/o3/rename_impl.hh b/src/cpu/o3/rename_impl.hh index bc024f603..a295a8705 100644 --- a/src/cpu/o3/rename_impl.hh +++ b/src/cpu/o3/rename_impl.hh @@ -524,8 +524,6 @@ DefaultRename<Impl>::renameInsts(ThreadID tid) ++renameRunCycles; } - DynInstPtr inst; - // Will have to do a different calculation for the number of free // entries. int free_rob_entries = calcFreeROBEntries(tid); @@ -596,7 +594,7 @@ DefaultRename<Impl>::renameInsts(ThreadID tid) assert(!insts_to_rename.empty()); - inst = insts_to_rename.front(); + DynInstPtr inst = insts_to_rename.front(); //For all kind of instructions, check ROB and IQ first //For load instruction, check LQ size and take into account the inflight loads @@ -787,7 +785,7 @@ DefaultRename<Impl>::sortInsts() { int insts_from_decode = fromDecode->size; for (int i = 0; i < insts_from_decode; ++i) { - DynInstPtr inst = fromDecode->insts[i]; + const DynInstPtr &inst = fromDecode->insts[i]; insts[inst->threadNumber].push_back(inst); #if TRACING_ON if (DTRACE(O3PipeView)) { @@ -1008,7 +1006,7 @@ DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, ThreadID tid) template <class Impl> inline void -DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst, ThreadID tid) +DefaultRename<Impl>::renameSrcRegs(const DynInstPtr &inst, ThreadID tid) { ThreadContext *tc = inst->tcBase(); RenameMap *map = renameMap[tid]; @@ -1068,7 +1066,7 @@ DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst, ThreadID tid) template <class Impl> inline void -DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst, ThreadID tid) +DefaultRename<Impl>::renameDestRegs(const DynInstPtr &inst, ThreadID tid) { ThreadContext *tc = inst->tcBase(); RenameMap *map = renameMap[tid]; |