Class Hierarchy Analysis (CHA)
The class linker now tracks whether a method has a single implementation
and if so, the JIT compiler will try to devirtualize a virtual call for
the method into a direct call. If the single-implementation assumption
is violated due to additional class linking, compiled code that makes the
assumption is invalidated. Deoptimization is triggered for compiled code
live on stack. Instead of patching return pc's on stack, a CHA guard is
added which checks a hidden should_deoptimize flag for deoptimization.
This approach limits the number of deoptimization points.
This CL does not devirtualize abstract/interface method invocation.
Slides on CHA:
https://docs.google.com/a/google.com/presentation/d/1Ax6cabP1vM44aLOaJU3B26n5fTE9w5YU-1CRevIDsBc/edit?usp=sharing
Change-Id: I18bf716a601b6413b46312e925a6ad9e4008efa4
Test: ART_TEST_JIT=true m test-art-host/target-run-test test-art-host-gtest
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 153aff4..a7a451f 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -793,7 +793,7 @@
// Update quick method header.
DCHECK_LT(method_offsets_index_, oat_class->method_headers_.size());
OatQuickMethodHeader* method_header = &oat_class->method_headers_[method_offsets_index_];
- uint32_t vmap_table_offset = method_header->vmap_table_offset_;
+ uint32_t vmap_table_offset = method_header->GetVmapTableOffset();
// The code offset was 0 when the mapping/vmap table offset was set, so it's set
// to 0-offset and we need to adjust it by code_offset.
uint32_t code_offset = quick_code_offset - thumb_offset;
@@ -935,7 +935,7 @@
// If vdex is enabled, we only emit the stack map of compiled code. The quickening info will
// be in the vdex file.
if (!compiled_method->GetQuickCode().empty() || !kIsVdexEnabled) {
- DCHECK_EQ(oat_class->method_headers_[method_offsets_index_].vmap_table_offset_, 0u);
+ DCHECK_EQ(oat_class->method_headers_[method_offsets_index_].GetVmapTableOffset(), 0u);
ArrayRef<const uint8_t> map = compiled_method->GetVmapTable();
uint32_t map_size = map.size() * sizeof(map[0]);
@@ -949,7 +949,7 @@
});
// Code offset is not initialized yet, so set the map offset to 0u-offset.
DCHECK_EQ(oat_class->method_offsets_[method_offsets_index_].code_offset_, 0u);
- oat_class->method_headers_[method_offsets_index_].vmap_table_offset_ = 0u - offset;
+ oat_class->method_headers_[method_offsets_index_].SetVmapTableOffset(0u - offset);
}
}
++method_offsets_index_;
@@ -1406,7 +1406,7 @@
size_t file_offset = file_offset_;
OutputStream* out = out_;
- uint32_t map_offset = oat_class->method_headers_[method_offsets_index_].vmap_table_offset_;
+ uint32_t map_offset = oat_class->method_headers_[method_offsets_index_].GetVmapTableOffset();
uint32_t code_offset = oat_class->method_offsets_[method_offsets_index_].code_offset_;
++method_offsets_index_;