Fix unaligned accesses in back_edge tables.

src/deoptimizer.cc

Index: src/deoptimizer.cc
diff --git a/src/deoptimizer.cc b/src/deoptimizer.cc
index 5f59fd9ab05584e96fec88e23ed8598ab5a0bc9b..ed8ce45c671e6419e9de01b565b994965f3756e8 100644
--- a/src/deoptimizer.cc
+++ b/src/deoptimizer.cc
@@ -2367,8 +2367,8 @@ void Deoptimizer::PatchInterruptCode(Code* unoptimized_code,
   uint32_t table_length = Memory::uint32_at(back_edge_cursor);
   back_edge_cursor += kIntSize;
   for (uint32_t i = 0; i < table_length; ++i) {
-    uint8_t loop_depth = Memory::uint8_at(back_edge_cursor + 2 * kIntSize);
-    if (loop_depth == loop_nesting_level) {
+    uint32_t loop_depth = Memory::uint32_at(back_edge_cursor + 2 * kIntSize);
+    if (static_cast<int>(loop_depth) == loop_nesting_level) {
       // Loop back edge has the loop depth that we want to patch.
       uint32_t pc_offset = Memory::uint32_at(back_edge_cursor + kIntSize);
       Address pc_after = unoptimized_code->instruction_start() + pc_offset;
@@ -2399,8 +2399,8 @@ void Deoptimizer::RevertInterruptCode(Code* unoptimized_code,
   uint32_t table_length = Memory::uint32_at(back_edge_cursor);
   back_edge_cursor += kIntSize;
   for (uint32_t i = 0; i < table_length; ++i) {
-    uint8_t loop_depth = Memory::uint8_at(back_edge_cursor + 2 * kIntSize);
-    if (loop_depth <= loop_nesting_level) {
+    uint32_t loop_depth = Memory::uint32_at(back_edge_cursor + 2 * kIntSize);
+    if (static_cast<int>(loop_depth) <= loop_nesting_level) {
       uint32_t pc_offset = Memory::uint32_at(back_edge_cursor + kIntSize);
       Address pc_after = unoptimized_code->instruction_start() + pc_offset;
       RevertInterruptCodeAt(unoptimized_code,
@@ -2431,7 +2431,7 @@ void Deoptimizer::VerifyInterruptCode(Code* unoptimized_code,
   uint32_t table_length = Memory::uint32_at(back_edge_cursor);
   back_edge_cursor += kIntSize;
   for (uint32_t i = 0; i < table_length; ++i) {
-    uint8_t loop_depth = Memory::uint8_at(back_edge_cursor + 2 * kIntSize);
+    int32_t loop_depth = Memory::int32_at(back_edge_cursor + 2 * kIntSize);

[kisg, 2013/07/18 15:46:52]

Instead of int32_t, use uint32_t and static_cast<int> in the CHECK to fix debug
builds

[kilvadyb, 2013/07/18 18:22:43]

Done.

     CHECK_LE(loop_depth, Code::kMaxLoopNestingMarker);
     // Assert that all back edges for shallower loops (and only those)
     // have already been patched.