Add implicit null pointer and stack overflow checks for Mips.
Bug: 21555893
Change-Id: I2a995be128a5603d08753c14956dd8c8240ac63c
diff --git a/compiler/dex/quick/mips/call_mips.cc b/compiler/dex/quick/mips/call_mips.cc
index da12d8e..853980d 100644
--- a/compiler/dex/quick/mips/call_mips.cc
+++ b/compiler/dex/quick/mips/call_mips.cc
@@ -24,6 +24,7 @@
#include "dex/quick/dex_file_to_method_inliner_map.h"
#include "dex/quick/mir_to_lir-inl.h"
#include "driver/compiler_driver.h"
+#include "driver/compiler_options.h"
#include "entrypoints/quick/quick_entrypoints.h"
#include "gc/accounting/card_table.h"
#include "mips_lir.h"
@@ -285,12 +286,25 @@
RegStorage check_reg = AllocPtrSizeTemp();
RegStorage new_sp = AllocPtrSizeTemp();
const RegStorage rs_sp = TargetPtrReg(kSp);
+ const size_t kStackOverflowReservedUsableBytes = GetStackOverflowReservedBytes(target);
+ const bool large_frame = static_cast<size_t>(frame_size_) > kStackOverflowReservedUsableBytes;
+ bool generate_explicit_stack_overflow_check = large_frame ||
+ !cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks();
+
if (!skip_overflow_check) {
- // Load stack limit.
- if (cu_->target64) {
- LoadWordDisp(TargetPtrReg(kSelf), Thread::StackEndOffset<8>().Int32Value(), check_reg);
+ if (generate_explicit_stack_overflow_check) {
+ // Load stack limit.
+ if (cu_->target64) {
+ LoadWordDisp(TargetPtrReg(kSelf), Thread::StackEndOffset<8>().Int32Value(), check_reg);
+ } else {
+ Load32Disp(TargetPtrReg(kSelf), Thread::StackEndOffset<4>().Int32Value(), check_reg);
+ }
} else {
- Load32Disp(TargetPtrReg(kSelf), Thread::StackEndOffset<4>().Int32Value(), check_reg);
+ // Implicit stack overflow check.
+ // Generate a load from [sp, #-overflowsize]. If this is in the stack
+ // redzone we will get a segmentation fault.
+ Load32Disp(rs_sp, -kStackOverflowReservedUsableBytes, rs_rZERO);
+ MarkPossibleStackOverflowException();
}
}
// Spill core callee saves.
@@ -298,7 +312,7 @@
// NOTE: promotion of FP regs currently unsupported, thus no FP spill.
DCHECK_EQ(num_fp_spills_, 0);
const int frame_sub = frame_size_ - spill_count * ptr_size;
- if (!skip_overflow_check) {
+ if (!skip_overflow_check && generate_explicit_stack_overflow_check) {
class StackOverflowSlowPath : public LIRSlowPath {
public:
StackOverflowSlowPath(Mir2Lir* m2l, LIR* branch, size_t sp_displace)
@@ -329,6 +343,8 @@
OpRegCopy(rs_sp, new_sp); // Establish stack.
cfi_.AdjustCFAOffset(frame_sub);
} else {
+ // Here if skip_overflow_check or doing implicit stack overflow check.
+ // Just make room on the stack for the frame now.
OpRegImm(kOpSub, rs_sp, frame_sub);
cfi_.AdjustCFAOffset(frame_sub);
}
diff --git a/compiler/dex/quick/mips/codegen_mips.h b/compiler/dex/quick/mips/codegen_mips.h
index 713264e..43fbcbd 100644
--- a/compiler/dex/quick/mips/codegen_mips.h
+++ b/compiler/dex/quick/mips/codegen_mips.h
@@ -79,6 +79,7 @@
OVERRIDE;
LIR* CheckSuspendUsingLoad() OVERRIDE;
RegStorage LoadHelper(QuickEntrypointEnum trampoline) OVERRIDE;
+ void ForceImplicitNullCheck(RegStorage reg, int opt_flags, bool is_wide);
LIR* LoadBaseDisp(RegStorage r_base, int displacement, RegStorage r_dest, OpSize size,
VolatileKind is_volatile) OVERRIDE;
LIR* LoadBaseIndexed(RegStorage r_base, RegStorage r_index, RegStorage r_dest, int scale,
diff --git a/compiler/dex/quick/mips/int_mips.cc b/compiler/dex/quick/mips/int_mips.cc
index f5ad7c7..1099303 100644
--- a/compiler/dex/quick/mips/int_mips.cc
+++ b/compiler/dex/quick/mips/int_mips.cc
@@ -691,6 +691,9 @@
reg_len = AllocTemp();
// Get len.
Load32Disp(rl_array.reg, len_offset, reg_len);
+ MarkPossibleNullPointerException(opt_flags);
+ } else {
+ ForceImplicitNullCheck(rl_array.reg, opt_flags, false);
}
// reg_ptr -> array data.
OpRegRegImm(kOpAdd, reg_ptr, rl_array.reg, data_offset);
@@ -781,6 +784,9 @@
// NOTE: max live temps(4) here.
// Get len.
Load32Disp(rl_array.reg, len_offset, reg_len);
+ MarkPossibleNullPointerException(opt_flags);
+ } else {
+ ForceImplicitNullCheck(rl_array.reg, opt_flags, false);
}
// reg_ptr -> array data.
OpRegImm(kOpAdd, reg_ptr, data_offset);
diff --git a/compiler/dex/quick/mips/target_mips.cc b/compiler/dex/quick/mips/target_mips.cc
index 4c0bd83..b098bc2 100644
--- a/compiler/dex/quick/mips/target_mips.cc
+++ b/compiler/dex/quick/mips/target_mips.cc
@@ -791,6 +791,7 @@
RegStorage reg_ptr = TargetReg(kArg0);
OpRegRegImm(kOpAdd, reg_ptr, r_base, displacement);
RegStorage r_tgt = LoadHelper(kQuickA64Load);
+ ForceImplicitNullCheck(reg_ptr, 0, true); // is_wide = true
LIR *ret = OpReg(kOpBlx, r_tgt);
RegStorage reg_ret;
if (cu_->target64) {
@@ -813,6 +814,7 @@
LockCallTemps(); // Using fixed registers.
RegStorage temp_ptr = AllocTemp();
OpRegRegImm(kOpAdd, temp_ptr, r_base, displacement);
+ ForceImplicitNullCheck(temp_ptr, 0, true); // is_wide = true
RegStorage temp_value = AllocTempWide();
OpRegCopyWide(temp_value, r_src);
if (cu_->target64) {
diff --git a/compiler/dex/quick/mips/utility_mips.cc b/compiler/dex/quick/mips/utility_mips.cc
index 95c61cd..37e5804 100644
--- a/compiler/dex/quick/mips/utility_mips.cc
+++ b/compiler/dex/quick/mips/utility_mips.cc
@@ -21,7 +21,9 @@
#include "base/logging.h"
#include "dex/quick/mir_to_lir-inl.h"
#include "dex/reg_storage_eq.h"
+#include "dex/mir_graph.h"
#include "driver/compiler_driver.h"
+#include "driver/compiler_options.h"
#include "mips_lir.h"
namespace art {
@@ -830,6 +832,22 @@
return res;
}
+void MipsMir2Lir::ForceImplicitNullCheck(RegStorage reg, int opt_flags, bool is_wide) {
+ if (cu_->compiler_driver->GetCompilerOptions().GetImplicitNullChecks()) {
+ if (!(cu_->disable_opt & (1 << kNullCheckElimination)) && (opt_flags & MIR_IGNORE_NULL_CHECK)) {
+ return;
+ }
+ // Force an implicit null check by performing a memory operation (load) from the given
+ // register with offset 0. This will cause a signal if the register contains 0 (null).
+ LIR* load = Load32Disp(reg, LOWORD_OFFSET, rs_rZERO);
+ MarkSafepointPC(load);
+ if (is_wide) {
+ load = Load32Disp(reg, HIWORD_OFFSET, rs_rZERO);
+ MarkSafepointPC(load);
+ }
+ }
+}
+
LIR* MipsMir2Lir::LoadBaseDisp(RegStorage r_base, int displacement, RegStorage r_dest, OpSize size,
VolatileKind is_volatile) {
if (UNLIKELY(is_volatile == kVolatile && (size == k64 || size == kDouble))