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/arm/utility_arm.cc b/compiler/dex/quick/arm/utility_arm.cc
index 1ec0a2c..8df5b25 100644
--- a/compiler/dex/quick/arm/utility_arm.cc
+++ b/compiler/dex/quick/arm/utility_arm.cc
@@ -828,6 +828,7 @@
int encoded_disp = displacement;
bool already_generated = false;
int dest_low_reg = r_dest.IsPair() ? r_dest.GetLowReg() : r_dest.GetReg();
+ bool null_pointer_safepoint = false;
switch (size) {
case kDouble:
case kLong:
@@ -848,6 +849,7 @@
displacement >> 2);
} else {
load = LoadBaseDispBody(r_base, displacement, r_dest.GetLow(), kWord, s_reg);
+ null_pointer_safepoint = true;
LoadBaseDispBody(r_base, displacement + 4, r_dest.GetHigh(), kWord, INVALID_SREG);
}
already_generated = true;
@@ -939,6 +941,11 @@
// TODO: in future may need to differentiate Dalvik accesses w/ spills
if (r_base == rs_rARM_SP) {
AnnotateDalvikRegAccess(load, displacement >> 2, true /* is_load */, r_dest.Is64Bit());
+ } else {
+ // We might need to generate a safepoint if we have two store instructions (wide or double).
+ if (!Runtime::Current()->ExplicitNullChecks() && null_pointer_safepoint) {
+ MarkSafepointPC(load);
+ }
}
return load;
}
@@ -965,6 +972,7 @@
int encoded_disp = displacement;
bool already_generated = false;
int src_low_reg = r_src.IsPair() ? r_src.GetLowReg() : r_src.GetReg();
+ bool null_pointer_safepoint = false;
switch (size) {
case kLong:
case kDouble:
@@ -974,6 +982,7 @@
displacement >> 2);
} else {
store = StoreBaseDispBody(r_base, displacement, r_src.GetLow(), kWord);
+ null_pointer_safepoint = true;
StoreBaseDispBody(r_base, displacement + 4, r_src.GetHigh(), kWord);
}
already_generated = true;
@@ -1061,6 +1070,11 @@
// TODO: In future, may need to differentiate Dalvik & spill accesses
if (r_base == rs_rARM_SP) {
AnnotateDalvikRegAccess(store, displacement >> 2, false /* is_load */, r_src.Is64Bit());
+ } else {
+ // We might need to generate a safepoint if we have two store instructions (wide or double).
+ if (!Runtime::Current()->ExplicitNullChecks() && null_pointer_safepoint) {
+ MarkSafepointPC(store);
+ }
}
return store;
}