commit cb73fb35e5f7c575ed491c0c8e2d2b1a0a22ea2e
author Jean Christophe Beyler <jean.christophe.beyler@intel.com> Thu May 01 15:36:22 2014 -0700
committer Jean Christophe Beyler <jean.christophe.beyler@intel.com> Fri May 02 13:20:32 2014 -0700
tree e89c34c5bb21f69c8c0104ba4b679a0a1e28dbce
parent 851a9a9c0c9b94e24eb0b3d322e810bb388a81a0

ART: Better SSA Allocation when recreating SSA

The SSA calculation is not allocation friendly. This makes the
SSARepresentation remember how much is allocated and not reallocate
if SSA should be recalculated.

Also added some allocation friendly code for the dominance code.

Signed-off-by: Jean Christophe Beyler <jean.christophe.beyler@intel.com>
Change-Id: I6418b402434bd850b45771c75b7631b7b84a8f66

compiler/dex/mir_dataflow.cc

diff --git a/compiler/dex/mir_dataflow.cc b/compiler/dex/mir_dataflow.cc
index 36f1be7..cd41d0f 100644
--- a/compiler/dex/mir_dataflow.cc
+++ b/compiler/dex/mir_dataflow.cc
@@ -947,18 +947,34 @@
   defs[reg_index] = ssa_reg;
 }
 
+void MIRGraph::AllocateSSAUseData(MIR *mir, int num_uses) {
+  mir->ssa_rep->num_uses = num_uses;
+
+  if (mir->ssa_rep->num_uses_allocated < num_uses) {
+    mir->ssa_rep->uses = static_cast<int*>(arena_->Alloc(sizeof(int) * num_uses, kArenaAllocDFInfo));
+    // NOTE: will be filled in during type & size inference pass
+    mir->ssa_rep->fp_use = static_cast<bool*>(arena_->Alloc(sizeof(bool) * num_uses, kArenaAllocDFInfo));
+  }
+}
+
+void MIRGraph::AllocateSSADefData(MIR *mir, int num_defs) {
+  mir->ssa_rep->num_defs = num_defs;
+
+  if (mir->ssa_rep->num_defs_allocated < num_defs) {
+    mir->ssa_rep->defs = static_cast<int*>(arena_->Alloc(sizeof(int) * num_defs,
+          kArenaAllocDFInfo));
+    mir->ssa_rep->fp_def = static_cast<bool*>(arena_->Alloc(sizeof(bool) * num_defs,
+          kArenaAllocDFInfo));
+  }
+}
+
 /* Look up new SSA names for format_35c instructions */
 void MIRGraph::DataFlowSSAFormat35C(MIR* mir) {
   DecodedInstruction *d_insn = &mir->dalvikInsn;
   int num_uses = d_insn->vA;
   int i;
 
-  mir->ssa_rep->num_uses = num_uses;
-  mir->ssa_rep->uses = static_cast<int*>(arena_->Alloc(sizeof(int) * num_uses,
-                                                       kArenaAllocDFInfo));
-  // NOTE: will be filled in during type & size inference pass
-  mir->ssa_rep->fp_use = static_cast<bool*>(arena_->Alloc(sizeof(bool) * num_uses,
-                                                          kArenaAllocDFInfo));
+  AllocateSSAUseData(mir, num_uses);
 
   for (i = 0; i < num_uses; i++) {
     HandleSSAUse(mir->ssa_rep->uses, d_insn->arg[i], i);
@@ -971,12 +987,7 @@
   int num_uses = d_insn->vA;
   int i;
 
-  mir->ssa_rep->num_uses = num_uses;
-  mir->ssa_rep->uses = static_cast<int*>(arena_->Alloc(sizeof(int) * num_uses,
-                                                       kArenaAllocDFInfo));
-  // NOTE: will be filled in during type & size inference pass
-  mir->ssa_rep->fp_use = static_cast<bool*>(arena_->Alloc(sizeof(bool) * num_uses,
-                                                          kArenaAllocDFInfo));
+  AllocateSSAUseData(mir, num_uses);
 
   for (i = 0; i < num_uses; i++) {
     HandleSSAUse(mir->ssa_rep->uses, d_insn->vC+i, i);
@@ -989,10 +1000,17 @@
 
   if (bb->data_flow_info == NULL) return false;
 
+  bb->data_flow_info->vreg_to_ssa_map_entrance =
+    static_cast<int*>(arena_->Alloc(sizeof(int) * cu_->num_dalvik_registers, kArenaAllocDFInfo));
+
+  memcpy(bb->data_flow_info->vreg_to_ssa_map_entrance, vreg_to_ssa_map_,
+      sizeof(int) * cu_->num_dalvik_registers);
+
   for (mir = bb->first_mir_insn; mir != NULL; mir = mir->next) {
     mir->ssa_rep =
         static_cast<struct SSARepresentation *>(arena_->Alloc(sizeof(SSARepresentation),
                                                               kArenaAllocDFInfo));
+    memset(mir->ssa_rep, 0, sizeof(*mir->ssa_rep));
 
     uint64_t df_attributes = oat_data_flow_attributes_[mir->dalvikInsn.opcode];
 
@@ -1039,13 +1057,7 @@
       }
     }
 
-    if (num_uses) {
-      mir->ssa_rep->num_uses = num_uses;
-      mir->ssa_rep->uses = static_cast<int*>(arena_->Alloc(sizeof(int) * num_uses,
-                                                           kArenaAllocDFInfo));
-      mir->ssa_rep->fp_use = static_cast<bool*>(arena_->Alloc(sizeof(bool) * num_uses,
-                                                              kArenaAllocDFInfo));
-    }
+    AllocateSSAUseData(mir, num_uses);
 
     int num_defs = 0;
 
@@ -1056,13 +1068,7 @@
       }
     }
 
-    if (num_defs) {
-      mir->ssa_rep->num_defs = num_defs;
-      mir->ssa_rep->defs = static_cast<int*>(arena_->Alloc(sizeof(int) * num_defs,
-                                                           kArenaAllocDFInfo));
-      mir->ssa_rep->fp_def = static_cast<bool*>(arena_->Alloc(sizeof(bool) * num_defs,
-                                                              kArenaAllocDFInfo));
-    }
+    AllocateSSADefData(mir, num_defs);
 
     DecodedInstruction *d_insn = &mir->dalvikInsn;
 
@@ -1108,11 +1114,11 @@
    * input to PHI nodes can be derived from the snapshot of all
    * predecessor blocks.
    */
-  bb->data_flow_info->vreg_to_ssa_map =
+  bb->data_flow_info->vreg_to_ssa_map_exit =
       static_cast<int*>(arena_->Alloc(sizeof(int) * cu_->num_dalvik_registers,
                                       kArenaAllocDFInfo));
 
-  memcpy(bb->data_flow_info->vreg_to_ssa_map, vreg_to_ssa_map_,
+  memcpy(bb->data_flow_info->vreg_to_ssa_map_exit, vreg_to_ssa_map_,
          sizeof(int) * cu_->num_dalvik_registers);
   return true;
 }