Revert "VM: New calling convention for generated code."

runtime/vm/assembler_arm64.h

Index: runtime/vm/assembler_arm64.h
diff --git a/runtime/vm/assembler_arm64.h b/runtime/vm/assembler_arm64.h
index 9aff4ddf8e9a57825a2722a050cbfa7069a9d302..6a70ff884b8f2de210d5bd3b237e943235e6ef11 100644
--- a/runtime/vm/assembler_arm64.h
+++ b/runtime/vm/assembler_arm64.h
@@ -1152,11 +1152,11 @@ class Assembler : public ValueObject {
     add(TMP, PP, Operand(kHeapObjectTag));
     str(TMP, Address(SP, -1 * kWordSize, Address::PreIndex));
   }
-  void TagAndPushPPAndPcMarker() {
-    COMPILE_ASSERT(CODE_REG != TMP2);
+  void TagAndPushPPAndPcMarker(Register pc_marker_reg) {
+    ASSERT(pc_marker_reg != TMP2);
     // Add the heap object tag back to PP before putting it on the stack.
     add(TMP2, PP, Operand(kHeapObjectTag));
-    stp(TMP2, CODE_REG,
+    stp(TMP2, pc_marker_reg,
         Address(SP, -2 * kWordSize, Address::PairPreIndex));
   }
   void PopAndUntagPP() {
@@ -1198,14 +1198,14 @@ class Assembler : public ValueObject {
     LslImmediate(dst, src, kSmiTagSize);
   }
 
-  void Branch(const StubEntry& stub_entry,
-              Register pp,
-              Patchability patchable = kNotPatchable);
+  void Branch(const StubEntry& stub_entry);
   void BranchPatchable(const StubEntry& stub_entry);
 
-  void BranchLink(const StubEntry& stub_entry,
-                  Patchability patchable = kNotPatchable);
+  void BranchLink(const ExternalLabel* label);
+  void BranchLink(const StubEntry& stub_entry);
 
+  // BranchLinkPatchable must be a fixed-length sequence so we can patch it
+  // with the debugger.
   void BranchLinkPatchable(const StubEntry& stub_entry);
 
   // Macros accepting a pp Register argument may attempt to load values from
@@ -1283,6 +1283,8 @@ class Assembler : public ValueObject {
     constant_pool_allowed_ = b;
   }
 
+  void LoadWordFromPoolOffset(Register dst, uint32_t offset);
+  void LoadWordFromPoolOffsetFixed(Register dst, uint32_t offset);
   intptr_t FindImmediate(int64_t imm);
   bool CanLoadFromObjectPool(const Object& object) const;
   void LoadExternalLabel(Register dst, const ExternalLabel* label);
@@ -1338,12 +1340,9 @@ class Assembler : public ValueObject {
     sub(CSP, CSP, Operand(reserved_space));
   }
 
-  void CheckCodePointer();
-  void RestoreCodePointer();
-
   void EnterDartFrame(intptr_t frame_size, Register new_pp = kNoRegister);
   void EnterOsrFrame(intptr_t extra_size, Register new_pp);
-  void LeaveDartFrame(RestorePP restore_pp = kRestoreCallerPP);
+  void LeaveDartFrame();
 
   void EnterCallRuntimeFrame(intptr_t frame_size);
   void LeaveCallRuntimeFrame();
@@ -1427,8 +1426,9 @@ class Assembler : public ValueObject {
 
   bool constant_pool_allowed_;
 
-  void LoadWordFromPoolOffset(Register dst, uint32_t offset, Register pp = PP);
-  void LoadWordFromPoolOffsetFixed(Register dst, uint32_t offset);
+  void Branch(const ExternalLabel* label);
+  void BranchPatchable(const ExternalLabel* label);
+  void BranchLinkPatchable(const ExternalLabel* label);
 
   void LoadObjectHelper(Register dst, const Object& obj, bool is_unique);