commit d4750f202170a448119c1813a964574bfea0dded
author Bill Buzbee <buzbee@android.com> Fri May 23 23:00:22 2014 +0000
committer Bill Buzbee <buzbee@android.com> Fri May 23 23:00:22 2014 +0000
tree b324f2a3ce4b216e98084d0a586fdbea806cd1ce
parent cb73fb35e5f7c575ed491c0c8e2d2b1a0a22ea2e

Revert "ART: Better SSA Allocation when recreating SSA"

Temporarily reverting until memory footprint cost of adding a vreg to ssa entrance map on every applicable MIR node can be assessed..

This reverts commit cb73fb35e5f7c575ed491c0c8e2d2b1a0a22ea2e.

Change-Id: Ia9c03bfc5d365ad8d8b949e870f1e3bcda7f9a54

compiler/dex/mir_dataflow.cc

diff --git a/compiler/dex/mir_dataflow.cc b/compiler/dex/mir_dataflow.cc
index cd41d0f..36f1be7 100644
--- a/compiler/dex/mir_dataflow.cc
+++ b/compiler/dex/mir_dataflow.cc
@@ -947,34 +947,18 @@
   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;
 
-  AllocateSSAUseData(mir, num_uses);
+  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));
 
   for (i = 0; i < num_uses; i++) {
     HandleSSAUse(mir->ssa_rep->uses, d_insn->arg[i], i);
@@ -987,7 +971,12 @@
   int num_uses = d_insn->vA;
   int i;
 
-  AllocateSSAUseData(mir, num_uses);
+  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));
 
   for (i = 0; i < num_uses; i++) {
     HandleSSAUse(mir->ssa_rep->uses, d_insn->vC+i, i);
@@ -1000,17 +989,10 @@
 
   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];
 
@@ -1057,7 +1039,13 @@
       }
     }
 
-    AllocateSSAUseData(mir, num_uses);
+    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));
+    }
 
     int num_defs = 0;
 
@@ -1068,7 +1056,13 @@
       }
     }
 
-    AllocateSSADefData(mir, num_defs);
+    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));
+    }
 
     DecodedInstruction *d_insn = &mir->dalvikInsn;
 
@@ -1114,11 +1108,11 @@
    * input to PHI nodes can be derived from the snapshot of all
    * predecessor blocks.
    */
-  bb->data_flow_info->vreg_to_ssa_map_exit =
+  bb->data_flow_info->vreg_to_ssa_map =
       static_cast<int*>(arena_->Alloc(sizeof(int) * cu_->num_dalvik_registers,
                                       kArenaAllocDFInfo));
 
-  memcpy(bb->data_flow_info->vreg_to_ssa_map_exit, vreg_to_ssa_map_,
+  memcpy(bb->data_flow_info->vreg_to_ssa_map, vreg_to_ssa_map_,
          sizeof(int) * cu_->num_dalvik_registers);
   return true;
 }