src/share/vm/oops/methodData.cpp

rev 5903 : 8031752: Failed speculative optimizations should be reattempted when root of compilation is different
Summary: support for speculative traps that keep track of the root of the compilation in which a trap occurs.
Reviewed-by:
rev 5904 : imported patch spectrap-chris
rev 5906 : [mq]: spectrapunloading

*** 1515,1535 ****
  
    assert(profile_parameters_jsr292_only(), "inconsistent");
    return m->is_compiled_lambda_form();
  }
  
! void MethodData::clean_method_data(BoolObjectClosure* is_alive) {
!   for (ProfileData* data = first_data();
!        is_valid(data);
!        data = next_data(data)) {
!     data->clean_weak_klass_links(is_alive);
    }
!   ParametersTypeData* parameters = parameters_type_data();
!   if (parameters != NULL) {
!     parameters->clean_weak_klass_links(is_alive);
    }
  
  #ifdef ASSERT
    DataLayout* dp  = extra_data_base();
    DataLayout* end = extra_data_limit();
  
    for (; dp < end; dp = next_extra(dp)) {
--- 1515,1592 ----
  
    assert(profile_parameters_jsr292_only(), "inconsistent");
    return m->is_compiled_lambda_form();
  }
  
! void MethodData::clean_extra_data_helper(DataLayout* dp, int shift, bool reset) {
!   if (shift == 0) {
!     return;
    }
!   if (!reset) {
!     // Move all cells of trap entry at dp left by "shift" cells
!     intptr_t* start = (intptr_t*)dp;
!     intptr_t* end = (intptr_t*)next_extra(dp);
!     for (intptr_t* ptr = start; ptr < end; ptr++) {
!       *(ptr-shift) = *ptr;
      }
+   } else {
+     // Reset "shift" cells stopping at dp
+     intptr_t* start = ((intptr_t*)dp) - shift;
+     intptr_t* end = (intptr_t*)dp;
+     for (intptr_t* ptr = start; ptr < end; ptr++) {
+       *ptr = 0;
+     }
+   }
+ }
  
+ // Remove SpeculativeTrapData entries that reference an unloaded
+ // method
+ void MethodData::clean_extra_data(BoolObjectClosure* is_alive) {
+   DataLayout* dp  = extra_data_base();
+   DataLayout* end = extra_data_limit();
+ 
+   int shift = 0;
+   for (; dp < end; dp = next_extra(dp)) {
+     switch(dp->tag()) {
+     case DataLayout::speculative_trap_data_tag: {
+       SpeculativeTrapData* data = new SpeculativeTrapData(dp);
+       Method* m = data->method();
+       assert(m != NULL, "should have a method");
+       if (!m->method_holder()->is_loader_alive(is_alive)) {
+         // "shift" accumulates the number of cells for dead
+         // SpeculativeTrapData entries that have been seen so
+         // far. Following entries must be shifted left by that many
+         // cells to remove the dead SpeculativeTrapData entries.
+         shift += (int)((intptr_t*)next_extra(dp) - (intptr_t*)dp); 
+       } else {
+         // Shift this entry left if it follows dead
+         // SpeculativeTrapData entries
+         clean_extra_data_helper(dp, shift);
+       }
+       break;
+     }
+     case dp->DataLayout::bit_data_tag:
+       // Shift this entry left if it follows dead SpeculativeTrapData
+       // entries
+       clean_extra_data_helper(dp, shift);
+       continue;
+     case DataLayout::no_tag:
+     case DataLayout::arg_info_data_tag:
+       // We are at end of the live trap entries. The previous "shift"
+       // cells contain entries that are either dead or were shifted
+       // left. They need to be reset to no_tag
+       clean_extra_data_helper(dp, shift, true);
+       return;
+     default:
+       fatal(err_msg("unexpected tag %d", dp->tag()));
+     }
+   }
+ }
+ 
+ // Verify there's no unloaded method referenced by a
+ // SpeculativeTrapData entry
+ void MethodData::verify_extra_data_clean(BoolObjectClosure* is_alive) {
  #ifdef ASSERT
    DataLayout* dp  = extra_data_base();
    DataLayout* end = extra_data_limit();
  
    for (; dp < end; dp = next_extra(dp)) {
*** 1549,1553 ****
--- 1606,1625 ----
        fatal(err_msg("unexpected tag %d", dp->tag()));
      }
    }
  #endif
  }
+ 
+ void MethodData::clean_method_data(BoolObjectClosure* is_alive) {
+   for (ProfileData* data = first_data();
+        is_valid(data);
+        data = next_data(data)) {
+     data->clean_weak_klass_links(is_alive);
+   }
+   ParametersTypeData* parameters = parameters_type_data();
+   if (parameters != NULL) {
+     parameters->clean_weak_klass_links(is_alive);
+   }
+ 
+   clean_extra_data(is_alive);
+   verify_extra_data_clean(is_alive);
+ }