commit 4f0d07c783afef89703dce32c94440fc8621a29b
author Ian Rogers <irogers@google.com> Thu Oct 06 23:38:47 2011 -0700
committer Ian Rogers <irogers@google.com> Fri Oct 07 11:40:56 2011 -0700
tree f6f4b68d5afc6551c61d3e86153878d9891ea13a
parent 3ddac99d4dc6a036fac59d8f0bdc664ef619fb04

Spill possibly reference holding registers for runtime calls.

Live references may be in registers when we crawl a stack for GC during
a runtime call. Whilst an exception won't occur we need to save the
callee save registers into the frame so the stack crawl can find their
values. Create variants of the callee save method to save just the
registers that are necessary.

Change-Id: I6fa479bffcbc333fe846f9bd3ef2e626e0209ed9

src/compiler/codegen/arm/Thumb2/Gen.cc

diff --git a/src/compiler/codegen/arm/Thumb2/Gen.cc b/src/compiler/codegen/arm/Thumb2/Gen.cc
index b63c37f..c136660 100644
--- a/src/compiler/codegen/arm/Thumb2/Gen.cc
+++ b/src/compiler/codegen/arm/Thumb2/Gen.cc
@@ -981,22 +981,22 @@
 
     oatFlushAllRegs(cUnit);
     DCHECK_EQ(LW_SHAPE_THIN, 0);
-    loadValueDirectFixed(cUnit, rlSrc, r1);  // Get obj
+    loadValueDirectFixed(cUnit, rlSrc, r0);  // Get obj
     oatLockCallTemps(cUnit);  // Prepare for explicit register usage
-    genNullCheck(cUnit, rlSrc.sRegLow, r1, mir);
-    loadWordDisp(cUnit, rSELF, Thread::ThinLockIdOffset().Int32Value(), r3);
-    newLIR3(cUnit, kThumb2Ldrex, r2, r1,
+    genNullCheck(cUnit, rlSrc.sRegLow, r0, mir);
+    loadWordDisp(cUnit, rSELF, Thread::ThinLockIdOffset().Int32Value(), r2);
+    newLIR3(cUnit, kThumb2Ldrex, r1, r0,
             Object::MonitorOffset().Int32Value() >> 2); // Get object->lock
     // Align owner
-    opRegImm(cUnit, kOpLsl, r3, LW_LOCK_OWNER_SHIFT);
+    opRegImm(cUnit, kOpLsl, r2, LW_LOCK_OWNER_SHIFT);
     // Is lock unheld on lock or held by us (==threadId) on unlock?
-    newLIR4(cUnit, kThumb2Bfi, r3, r2, 0, LW_LOCK_OWNER_SHIFT - 1);
-    newLIR3(cUnit, kThumb2Bfc, r2, LW_HASH_STATE_SHIFT, LW_LOCK_OWNER_SHIFT - 1);
-    hopBranch = newLIR2(cUnit, kThumb2Cbnz, r2, 0);
-    newLIR4(cUnit, kThumb2Strex, r2, r3, r1,
+    newLIR4(cUnit, kThumb2Bfi, r2, r1, 0, LW_LOCK_OWNER_SHIFT - 1);
+    newLIR3(cUnit, kThumb2Bfc, r1, LW_HASH_STATE_SHIFT, LW_LOCK_OWNER_SHIFT - 1);
+    hopBranch = newLIR2(cUnit, kThumb2Cbnz, r1, 0);
+    newLIR4(cUnit, kThumb2Strex, r1, r2, r0,
             Object::MonitorOffset().Int32Value() >> 2);
     oatGenMemBarrier(cUnit, kSY);
-    branch = newLIR2(cUnit, kThumb2Cbz, r2, 0);
+    branch = newLIR2(cUnit, kThumb2Cbz, r1, 0);
 
     hopTarget = newLIR0(cUnit, kArmPseudoTargetLabel);
     hopTarget->defMask = ENCODE_ALL;
@@ -1005,7 +1005,6 @@
     // Go expensive route - artLockObjectFromCode(self, obj);
     loadWordDisp(cUnit, rSELF, OFFSETOF_MEMBER(Thread, pLockObjectFromCode),
                  rLR);
-    genRegCopy(cUnit, r0, rSELF);
     callRuntimeHelper(cUnit, rLR);
 
     // Resume here
@@ -1030,30 +1029,29 @@
 
     DCHECK_EQ(LW_SHAPE_THIN, 0);
     oatFlushAllRegs(cUnit);
-    loadValueDirectFixed(cUnit, rlSrc, r1);  // Get obj
+    loadValueDirectFixed(cUnit, rlSrc, r0);  // Get obj
     oatLockCallTemps(cUnit);  // Prepare for explicit register usage
-    genNullCheck(cUnit, rlSrc.sRegLow, r1, mir);
-    loadWordDisp(cUnit, r1, Object::MonitorOffset().Int32Value(), r2); // Get lock
-    loadWordDisp(cUnit, rSELF, Thread::ThinLockIdOffset().Int32Value(), r3);
+    genNullCheck(cUnit, rlSrc.sRegLow, r0, mir);
+    loadWordDisp(cUnit, r0, Object::MonitorOffset().Int32Value(), r1); // Get lock
+    loadWordDisp(cUnit, rSELF, Thread::ThinLockIdOffset().Int32Value(), r2);
     // Is lock unheld on lock or held by us (==threadId) on unlock?
-    opRegRegImm(cUnit, kOpAnd, r12, r2, (LW_HASH_STATE_MASK << LW_HASH_STATE_SHIFT));
+    opRegRegImm(cUnit, kOpAnd, r3, r1, (LW_HASH_STATE_MASK << LW_HASH_STATE_SHIFT));
     // Align owner
-    opRegImm(cUnit, kOpLsl, r3, LW_LOCK_OWNER_SHIFT);
-    newLIR3(cUnit, kThumb2Bfc, r2, LW_HASH_STATE_SHIFT, LW_LOCK_OWNER_SHIFT - 1);
-    opRegReg(cUnit, kOpSub, r2, r3);
+    opRegImm(cUnit, kOpLsl, r2, LW_LOCK_OWNER_SHIFT);
+    newLIR3(cUnit, kThumb2Bfc, r1, LW_HASH_STATE_SHIFT, LW_LOCK_OWNER_SHIFT - 1);
+    opRegReg(cUnit, kOpSub, r1, r2);
     hopBranch = opCondBranch(cUnit, kArmCondNe);
     oatGenMemBarrier(cUnit, kSY);
-    storeWordDisp(cUnit, r1, Object::MonitorOffset().Int32Value(), r12);
+    storeWordDisp(cUnit, r0, Object::MonitorOffset().Int32Value(), r3);
     branch = opNone(cUnit, kOpUncondBr);
 
     hopTarget = newLIR0(cUnit, kArmPseudoTargetLabel);
     hopTarget->defMask = ENCODE_ALL;
     hopBranch->generic.target = (LIR*)hopTarget;
 
-    // Go expensive route - UnlockObjectFromCode(self, obj);
+    // Go expensive route - UnlockObjectFromCode(obj);
     loadWordDisp(cUnit, rSELF, OFFSETOF_MEMBER(Thread, pUnlockObjectFromCode),
                  rLR);
-    genRegCopy(cUnit, r0, rSELF);
     callRuntimeHelper(cUnit, rLR);
 
     // Resume here