From 75969963213c39a029e01c3b9440fb388d793afb Mon Sep 17 00:00:00 2001
From: Goran Jakovljevic <Goran.Jakovljevic@imgtec.com>
Date: Tue, 27 Oct 2015 12:29:07 +0100
Subject: [PATCH] MIPS32: Move code from RA to T9 in longjump

Do not use the return address. It should not be clobbered as we
may need it, e.g., for single-frame deopt.

This fixes following tests:
* 449-checker-bce
* 534-checker-bce-deoptimization
* 535-deopt-and-inlining

Change-Id: Ic94a2897c7336da094a8937ab1bc4a02a680de53
---
 runtime/arch/mips/context_mips.cc          | 4 ++--
 runtime/arch/mips/context_mips.h           | 9 +++++----
 runtime/arch/mips/quick_entrypoints_mips.S | 2 +-
 test/Android.run-test.mk                   | 3 ---
 4 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/runtime/arch/mips/context_mips.cc b/runtime/arch/mips/context_mips.cc
index 4dedb3339..375a03ace 100644
--- a/runtime/arch/mips/context_mips.cc
+++ b/runtime/arch/mips/context_mips.cc
@@ -28,11 +28,11 @@ void MipsContext::Reset() {
   std::fill_n(gprs_, arraysize(gprs_), nullptr);
   std::fill_n(fprs_, arraysize(fprs_), nullptr);
   gprs_[SP] = &sp_;
-  gprs_[RA] = &ra_;
+  gprs_[T9] = &t9_;
   gprs_[A0] = &arg0_;
   // Initialize registers with easy to spot debug values.
   sp_ = MipsContext::kBadGprBase + SP;
-  ra_ = MipsContext::kBadGprBase + RA;
+  t9_ = MipsContext::kBadGprBase + T9;
   arg0_ = 0;
 }
 
diff --git a/runtime/arch/mips/context_mips.h b/runtime/arch/mips/context_mips.h
index f1e290559..7dcff630d 100644
--- a/runtime/arch/mips/context_mips.h
+++ b/runtime/arch/mips/context_mips.h
@@ -41,7 +41,7 @@ class MipsContext : public Context {
   }
 
   void SetPC(uintptr_t new_pc) OVERRIDE {
-    SetGPR(RA, new_pc);
+    SetGPR(T9, new_pc);
   }
 
   bool IsAccessibleGPR(uint32_t reg) OVERRIDE {
@@ -86,9 +86,10 @@ class MipsContext : public Context {
   // Pointers to registers in the stack, initialized to null except for the special cases below.
   uintptr_t* gprs_[kNumberOfCoreRegisters];
   uint32_t* fprs_[kNumberOfFRegisters];
-  // Hold values for sp and ra (return address) if they are not located within a stack frame, as
-  // well as the first argument.
-  uintptr_t sp_, ra_, arg0_;
+  // Hold values for sp and t9 if they are not located within a stack frame. We use t9 for the
+  // PC (as ra is required to be valid for single-frame deopt and must not be clobbered). We
+  // also need the first argument for single-frame deopt.
+  uintptr_t sp_, t9_, arg0_;
 };
 }  // namespace mips
 }  // namespace art
diff --git a/runtime/arch/mips/quick_entrypoints_mips.S b/runtime/arch/mips/quick_entrypoints_mips.S
index ba58c3fcc..0691f2a62 100644
--- a/runtime/arch/mips/quick_entrypoints_mips.S
+++ b/runtime/arch/mips/quick_entrypoints_mips.S
@@ -374,7 +374,7 @@ ENTRY art_quick_do_long_jump
     lw      $ra, 124($a0)
     lw      $a0, 16($a0)
     move    $v0, $zero          # clear result registers r0 and r1
-    jalr    $zero, $ra          # do long jump
+    jalr    $zero, $t9          # do long jump
     move    $v1, $zero
 END art_quick_do_long_jump
 
diff --git a/test/Android.run-test.mk b/test/Android.run-test.mk
index 5bbbbc1f5..6ce3d9472 100644
--- a/test/Android.run-test.mk
+++ b/test/Android.run-test.mk
@@ -441,11 +441,8 @@ TEST_ART_BROKEN_DEFAULT_RUN_TESTS :=
 # Known broken tests for the mips32 optimizing compiler backend.
 TEST_ART_BROKEN_OPTIMIZING_MIPS_RUN_TESTS := \
     441-checker-inliner \
-    449-checker-bce \
     510-checker-try-catch \
     521-checker-array-set-null \
-    529-checker-unresolved \
-    534-checker-bce-deoptimization \
     536-checker-intrinsic-optimization \
 
 ifeq (mips,$(TARGET_ARCH))
-- 
2.11.0