commit 4896d7b6fb75add25f2d6ba84346ac83d8ba9d51
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> Tue May 27 08:58:39 2014 -0700
tree b3e2da5fa23c984d4ed1f2f83429350edb67f929
parent 1b1aea22c0cc5567b5967590cb3f949cc45c3a9a

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.

Change-Id: Icd5586b7e2fefae8e1535975ab400b1ca95b500f
Signed-off-by: Jean Christophe Beyler <jean.christophe.beyler@intel.com>

compiler/dex/mir_dataflow.cc

diff --git a/compiler/dex/mir_dataflow.cc b/compiler/dex/mir_dataflow.cc
index ed7e1f5..47b233b 100644
--- a/compiler/dex/mir_dataflow.cc
+++ b/compiler/dex/mir_dataflow.cc
@@ -953,18 +953,34 @@
   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) {
   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);
@@ -977,12 +993,7 @@
   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);
@@ -999,6 +1010,7 @@
     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 = GetDataFlowAttributes(mir);
 
@@ -1045,13 +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;
 
@@ -1062,13 +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);
 
     MIR::DecodedInstruction* d_insn = &mir->dalvikInsn;
 
@@ -1114,11 +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;
 }