Change deoptimize entrypoint to save everything.

And implement FPU register retrieval from stack on x86.

On Nexus 9, AOSP ToT, the boot.oat size reduction is
  prebuilt multi-part boot image:
    - 32-bit boot.oat: -20KiB (-0.03%)
    - 64-bit boot.oat: -45KiB (-0.06%)
  on-device built single boot image:
    - 32-bit boot.oat: -24KiB (-0.04%)
    - 64-bit boot.oat: -36KiB (-0.05%)

Test: Run ART test suite on host and Nexus 9.
Bug: 30212852
Change-Id: I5d98e2a24363136d73dfec6100ab02f8eb101911

1 files changed, 5 insertions, 2 deletions

diff --git a/runtime/stack.cc b/runtime/stack.cc
index ec492edc4e..4678ac6e50 100644
--- a/runtime/stack.cc
+++ b/runtime/stack.cc
@@ -319,8 +319,11 @@ bool StackVisitor::GetVRegFromOptimizedCode(ArtMethod* m, uint16_t vreg, VRegKin
 bool StackVisitor::GetRegisterIfAccessible(uint32_t reg, VRegKind kind, uint32_t* val) const {
   const bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
 
-  // X86 float registers are 64-bit and the logic below does not apply.
-  DCHECK(!is_float || kRuntimeISA != InstructionSet::kX86);
+  if (kRuntimeISA == InstructionSet::kX86 && is_float) {
+    // X86 float registers are 64-bit and each XMM register is provided as two separate
+    // 32-bit registers by the context.
+    reg = (kind == kDoubleHiVReg) ? (2 * reg + 1) : (2 * reg);
+  }
 
   if (!IsAccessibleRegister(reg, is_float)) {
     return false;