Implement implicit stack overflow checks
This also fixes some failing run tests due to missing
null pointer markers.
The implementation of the implicit stack overflow checks introduces
the ability to have a gap in the stack that is skipped during
stack walk backs. This gap is protected against read/write and
is used to trigger a SIGSEGV at function entry if the stack
will overflow.
Change-Id: I0c3e214c8b87dc250cf886472c6d327b5d58653e
diff --git a/compiler/dex/quick/gen_common.cc b/compiler/dex/quick/gen_common.cc
index 2afa5ca..866ce5f 100644
--- a/compiler/dex/quick/gen_common.cc
+++ b/compiler/dex/quick/gen_common.cc
@@ -74,14 +74,19 @@
/* Perform null-check on a register. */
LIR* Mir2Lir::GenNullCheck(RegStorage m_reg, int opt_flags) {
if (Runtime::Current()->ExplicitNullChecks()) {
- if (!(cu_->disable_opt & (1 << kNullCheckElimination)) && (opt_flags & MIR_IGNORE_NULL_CHECK)) {
- return NULL;
- }
- return GenImmedCheck(kCondEq, m_reg, 0, kThrowNullPointer);
+ return GenExplicitNullCheck(m_reg, opt_flags);
}
return nullptr;
}
+/* Perform an explicit null-check on a register. */
+LIR* Mir2Lir::GenExplicitNullCheck(RegStorage m_reg, int opt_flags) {
+ if (!(cu_->disable_opt & (1 << kNullCheckElimination)) && (opt_flags & MIR_IGNORE_NULL_CHECK)) {
+ return NULL;
+ }
+ return GenImmedCheck(kCondEq, m_reg, 0, kThrowNullPointer);
+}
+
void Mir2Lir::MarkPossibleNullPointerException(int opt_flags) {
if (!Runtime::Current()->ExplicitNullChecks()) {
if (!(cu_->disable_opt & (1 << kNullCheckElimination)) && (opt_flags & MIR_IGNORE_NULL_CHECK)) {
@@ -732,6 +737,7 @@
OpRegRegImm(kOpAdd, reg_ptr, rl_obj.reg, field_info.FieldOffset().Int32Value());
rl_result = EvalLoc(rl_dest, reg_class, true);
LoadBaseDispWide(reg_ptr, 0, rl_result.reg, INVALID_SREG);
+ MarkPossibleNullPointerException(opt_flags);
if (field_info.IsVolatile()) {
// Without context sensitive analysis, we must issue the most conservative barriers.
// In this case, either a load or store may follow so we issue both barriers.