ART: skip compilation of huge methods.
Besides not being worthwhile to compile, it huge methods could cause
overflow of some internal compiler structures.
internal b/17524219
(cherry picked from commit bf5d818f7e59ce33521ad81bbab68b1e7a09e0ba)
Change-Id: If99b47c3191c69feee319c9d73537e827ba0cc1d
diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index b267841..07f3033 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -82,11 +82,22 @@
jobject class_loader, const DexFile& dex_file,
void* llvm_compilation_unit) {
VLOG(compiler) << "Compiling " << PrettyMethod(method_idx, dex_file) << "...";
- if (code_item->insns_size_in_code_units_ >= 0x10000) {
- LOG(INFO) << "Method size exceeds compiler limits: " << code_item->insns_size_in_code_units_
+ /*
+ * Skip compilation for pathologically large methods - either by instruction count or num vregs.
+ * Dalvik uses 16-bit uints for instruction and register counts. We'll limit to a quarter
+ * of that, which also guarantees we cannot overflow our 16-bit internal SSA name space.
+ */
+ if (code_item->insns_size_in_code_units_ >= UINT16_MAX / 4) {
+ LOG(INFO) << "Method exceeds compiler instruction limit: "
+ << code_item->insns_size_in_code_units_
<< " in " << PrettyMethod(method_idx, dex_file);
return NULL;
}
+ if (code_item->registers_size_ >= UINT16_MAX / 4) {
+ LOG(INFO) << "Method exceeds compiler virtual register limit: "
+ << code_item->registers_size_ << " in " << PrettyMethod(method_idx, dex_file);
+ return NULL;
+ }
if (!driver.GetCompilerOptions().IsCompilationEnabled()) {
return nullptr;