Minor suspend check tweak

Rearrange the suspend check branch for unconditional backwards
branches.  Now, the conditional branch on rSUSPEND will go directly
to the target in the common case, and fallthrough to an
unconditional branch to the suspend launchpad in the uncommon case.

Change-Id: Ie1a2b2fe720efde6e131a8d5274b7487fb644881

1 files changed, 30 insertions, 0 deletions

diff --git a/src/compiler/codegen/GenCommon.cc b/src/compiler/codegen/GenCommon.cc
index 54b8e5f95a..3cc594cc25 100644
--- a/src/compiler/codegen/GenCommon.cc
+++ b/src/compiler/codegen/GenCommon.cc
@@ -2503,4 +2503,34 @@ void genSuspendTest(CompilationUnit* cUnit, MIR* mir)
     }
 }
 
+/* Check if we need to check for pending suspend request */
+void genSuspendTestAndBranch(CompilationUnit* cUnit, MIR* mir, LIR* target)
+{
+    if (NO_SUSPEND || (mir->optimizationFlags & MIR_IGNORE_SUSPEND_CHECK)) {
+        opUnconditionalBranch(cUnit, target);
+        return;
+    }
+    if (cUnit->genDebugger) {
+        genSuspendTest(cUnit, mir);
+        opUnconditionalBranch(cUnit, target);
+    } else {
+#if defined(TARGET_ARM)
+        // In non-debug case, only check periodically
+        newLIR2(cUnit, kThumbSubRI8, rSUSPEND, 1);
+        opCondBranch(cUnit, kCondNe, target);
+#elif defined(TARGET_X86)
+        newLIR2(cUnit, kX86Cmp32TI, Thread::SuspendCountOffset().Int32Value(), 0);
+        opCondBranch(cUnit, kCondEq, target);
+#else
+        opRegImm(cUnit, kOpSub, rSUSPEND, 1);
+        opCmpImmBranch(cUnit, kCondNe, rSUSPEND, 0, target);
+#endif
+        LIR* launchPad = rawLIR(cUnit, cUnit->currentDalvikOffset,
+                                kPseudoSuspendTarget, (intptr_t)target, mir->offset);
+        oatFlushAllRegs(cUnit);
+        opUnconditionalBranch(cUnit, launchPad);
+        oatInsertGrowableList(cUnit, &cUnit->suspendLaunchpads, (intptr_t)launchPad);
+    }
+}
+
 }  // namespace art