am 9f54185b: Set "needFallThroughBranch" flag during block split.

* commit '9f54185b4186def90351903bb2e97090e06ab559':
  Set "needFallThroughBranch" flag during block split.

5 files changed, 32 insertions, 2 deletions

diff --git a/vm/compiler/Frontend.cpp b/vm/compiler/Frontend.cpp
index da693ea09..473f3d0d7 100644
--- a/vm/compiler/Frontend.cpp
+++ b/vm/compiler/Frontend.cpp
@@ -564,6 +564,7 @@ static BasicBlock *splitBlock(CompilationUnit *cUnit,
     }
 
     /* Handle the fallthrough path */
+    bottomBlock->needFallThroughBranch = origBlock->needFallThroughBranch;
     bottomBlock->fallThrough = origBlock->fallThrough;
     origBlock->fallThrough = bottomBlock;
     origBlock->needFallThroughBranch = true;
diff --git a/vm/compiler/Loop.cpp b/vm/compiler/Loop.cpp
index 89b8e0f14..90c97d767 100644
--- a/vm/compiler/Loop.cpp
+++ b/vm/compiler/Loop.cpp
@@ -552,7 +552,23 @@ bool dvmCompilerFilterLoopBlocks(CompilationUnit *cUnit)
      */
     while (true) {
         /* Loop formed */
-        if (bodyBB->taken == firstBB || bodyBB->fallThrough == firstBB) break;
+        if (bodyBB->taken == firstBB) {
+            /* Check if the fallThrough edge will cause a nested loop */
+            if (bodyBB->fallThrough &&
+                dvmIsBitSet(cUnit->tempBlockV, bodyBB->fallThrough->id)) {
+                return false;
+            }
+            /* Single loop formed */
+            break;
+        } else if (bodyBB->fallThrough == firstBB) {
+            /* Check if the taken edge will cause a nested loop */
+            if (bodyBB->taken &&
+                dvmIsBitSet(cUnit->tempBlockV, bodyBB->taken->id)) {
+                return false;
+            }
+            /* Single loop formed */
+            break;
+        }
 
         /* Inner loops formed first - quit */
         if (bodyBB->fallThrough &&
diff --git a/vm/compiler/codegen/arm/ArmLIR.h b/vm/compiler/codegen/arm/ArmLIR.h
index 864f5b63a..46316ff46 100644
--- a/vm/compiler/codegen/arm/ArmLIR.h
+++ b/vm/compiler/codegen/arm/ArmLIR.h
@@ -627,7 +627,7 @@ typedef enum ArmOpcode {
     kThumb2Dmb,          /* dmb [1111001110111111100011110101] option[3-0] */
     kThumb2LdrPcReln12,  /* ldr rd,[pc,-#imm12] [1111100011011111] rt[15-12]
                                   imm12[11-0] */
-
+    kThumbUndefined,     /* undefined [11011110xxxxxxxx] */
     kArmLast,
 } ArmOpcode;
 
diff --git a/vm/compiler/codegen/arm/Assemble.cpp b/vm/compiler/codegen/arm/Assemble.cpp
index 16804ba99..a433c31d4 100644
--- a/vm/compiler/codegen/arm/Assemble.cpp
+++ b/vm/compiler/codegen/arm/Assemble.cpp
@@ -881,6 +881,10 @@ ArmEncodingMap EncodingMap[kArmLast] = {
                  kFmtUnused, -1, -1,
                  IS_BINARY_OP | REG_DEF0 | REG_USE_PC | IS_LOAD,
                  "ldr", "r!0d, [r15pc, -#!1d]", 2),
+    ENCODING_MAP(kThumbUndefined,       0xde00,
+                 kFmtUnused, -1, -1, kFmtUnused, -1, -1, kFmtUnused, -1, -1,
+                 kFmtUnused, -1, -1, NO_OPERAND,
+                 "undefined", "", 1),
 };
 
 /*
diff --git a/vm/compiler/codegen/arm/CodegenDriver.cpp b/vm/compiler/codegen/arm/CodegenDriver.cpp
index c38b16a46..a722289eb 100644
--- a/vm/compiler/codegen/arm/CodegenDriver.cpp
+++ b/vm/compiler/codegen/arm/CodegenDriver.cpp
@@ -3896,6 +3896,15 @@ static void handlePCReconstruction(CompilationUnit *cUnit,
         (ArmLIR **) cUnit->pcReconstructionList.elemList;
     int numElems = cUnit->pcReconstructionList.numUsed;
     int i;
+
+    /*
+     * We should never reach here through fall-through code, so insert
+     * a bomb to signal troubles immediately.
+     */
+    if (numElems) {
+        newLIR0(cUnit, kThumbUndefined);
+    }
+
     for (i = 0; i < numElems; i++) {
         dvmCompilerAppendLIR(cUnit, (LIR *) pcrLabel[i]);
         /* r0 = dalvik PC */