commit 6702243ea2332b566d8e8b871cc9db0906d835ad
author Mathieu Chartier <mathieuc@google.com> Thu Nov 29 18:04:50 2012 -0800
committer Ian Rogers <irogers@google.com> Tue Dec 11 11:35:41 2012 -0800
tree dc530339fa07de6028c0771edb082f58ea3686f9
parent a169e1d8d968800380245cda450505d969ebff76

Support for SetVReg and add SetGPR.

These changes are useful for debugging and are required for being able
to change all GC roots.

MIPS is untested.

Change-Id: I2ba055de64264098bffe869a4fb192d0975f1c8f

src/stack.h

diff --git a/src/stack.h b/src/stack.h
index ce84807..ecfa846 100644
--- a/src/stack.h
+++ b/src/stack.h
@@ -51,9 +51,10 @@
   kUndefined,
 };
 
-// ShadowFrame has 3 possible layouts: portable (VRegs & references overlap),
-// interpreter (VRegs and separate references array), JNI (just VRegs, but where
-// VRegs really => references).
+// ShadowFrame has 3 possible layouts:
+//  - portable - a unified array of VRegs and references. Precise references need GC maps.
+//  - interpreter - separate VRegs and reference arrays. References are in the reference array.
+//  - JNI - just VRegs, but where every VReg holds a reference.
 class ShadowFrame {
  public:
   // Create ShadowFrame for interpreter.
@@ -77,7 +78,6 @@
   }
 
   void SetNumberOfVRegs(uint32_t number_of_vregs) {
-    DCHECK(number_of_vregs < kHasReferenceArray);
     number_of_vregs_ = number_of_vregs | (number_of_vregs_ & kHasReferenceArray);
   }
 
@@ -207,18 +207,21 @@
   ShadowFrame(uint32_t num_vregs, ShadowFrame* link, AbstractMethod* method, uint32_t dex_pc,
               bool has_reference_array)
       : number_of_vregs_(num_vregs), link_(link), method_(method), dex_pc_(dex_pc) {
+    CHECK_LT(num_vregs, static_cast<uint32_t>(kHasReferenceArray));
     if (has_reference_array) {
       number_of_vregs_ |= kHasReferenceArray;
       for (size_t i = 0; i < num_vregs; ++i) {
         SetVRegReference(i, NULL);
       }
-    }
-    for (size_t i = 0; i < num_vregs; ++i) {
-      SetVReg(i, 0);
+    } else {
+      for (size_t i = 0; i < num_vregs; ++i) {
+        SetVReg(i, 0);
+      }
     }
   }
 
   Object* const* References() const {
+    DCHECK(HasReferenceArray());
     const uint32_t* vreg_end = &vregs_[NumberOfVRegs()];
     return reinterpret_cast<Object* const*>(vreg_end);
   }
@@ -362,16 +365,15 @@
 
   size_t GetNativePcOffset() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
-  uintptr_t LoadCalleeSave(int num, size_t frame_size) const {
+  uintptr_t* CalleeSaveAddress(int num, size_t frame_size) const {
     // Callee saves are held at the top of the frame
-    AbstractMethod* method = GetMethod();
-    DCHECK(method != NULL);
+    DCHECK(GetMethod() != NULL);
     byte* save_addr =
         reinterpret_cast<byte*>(cur_quick_frame_) + frame_size - ((num + 1) * kPointerSize);
 #if defined(__i386__)
     save_addr -= kPointerSize;  // account for return address
 #endif
-    return *reinterpret_cast<uintptr_t*>(save_addr);
+    return reinterpret_cast<uintptr_t*>(save_addr);
   }
 
   // Returns the height of the stack in the managed stack frames, including transitions.
@@ -398,6 +400,7 @@
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   uintptr_t GetGPR(uint32_t reg) const;
+  void SetGPR(uint32_t reg, uintptr_t value);
 
   uint32_t GetVReg(AbstractMethod** cur_quick_frame, const DexFile::CodeItem* code_item,
                    uint32_t core_spills, uint32_t fp_spills, size_t frame_size,