Promote pointer to dex cache arrays on arm.
Do the use-count analysis on temps (ArtMethod* and the new
PC-relative temp) in Mir2Lir, rather than MIRGraph. MIRGraph
isn't really supposed to know how the ArtMethod* is used by
the backend.
Change-Id: Iaf56a46ae203eca86281b02b54f39a80fe5cc2dd
diff --git a/compiler/dex/quick/arm/utility_arm.cc b/compiler/dex/quick/arm/utility_arm.cc
index e4bd2a3..c3371cf 100644
--- a/compiler/dex/quick/arm/utility_arm.cc
+++ b/compiler/dex/quick/arm/utility_arm.cc
@@ -19,6 +19,7 @@
#include "arch/arm/instruction_set_features_arm.h"
#include "arm_lir.h"
#include "base/logging.h"
+#include "dex/mir_graph.h"
#include "dex/quick/mir_to_lir-inl.h"
#include "dex/reg_storage_eq.h"
#include "driver/compiler_driver.h"
@@ -1266,4 +1267,38 @@
return offset;
}
+void ArmMir2Lir::CountRefs(RefCounts* core_counts, RefCounts* fp_counts, size_t num_regs) {
+ // Start with the default counts.
+ Mir2Lir::CountRefs(core_counts, fp_counts, num_regs);
+
+ if (pc_rel_temp_ != nullptr) {
+ // Now, if the dex cache array base temp is used only once outside any loops (weight = 1),
+ // avoid the promotion, otherwise boost the weight by factor 4 because the full PC-relative
+ // load sequence is 4 instructions long.
+ int p_map_idx = SRegToPMap(pc_rel_temp_->s_reg_low);
+ if (core_counts[p_map_idx].count == 1) {
+ core_counts[p_map_idx].count = 0;
+ } else {
+ core_counts[p_map_idx].count *= 4;
+ }
+ }
+}
+
+void ArmMir2Lir::DoPromotion() {
+ if (CanUseOpPcRelDexCacheArrayLoad()) {
+ pc_rel_temp_ = mir_graph_->GetNewCompilerTemp(kCompilerTempBackend, false);
+ }
+
+ Mir2Lir::DoPromotion();
+
+ if (pc_rel_temp_ != nullptr) {
+ // Now, if the dex cache array base temp is promoted, remember the register but
+ // always remove the temp's stack location to avoid unnecessarily bloating the stack.
+ dex_cache_arrays_base_reg_ = mir_graph_->reg_location_[pc_rel_temp_->s_reg_low].reg;
+ DCHECK(!dex_cache_arrays_base_reg_.Valid() || !dex_cache_arrays_base_reg_.IsFloat());
+ mir_graph_->RemoveLastCompilerTemp(kCompilerTempBackend, false, pc_rel_temp_);
+ pc_rel_temp_ = nullptr;
+ }
+}
+
} // namespace art