[aarch64-port-dev ] Generate the self-patching vtable methods for shared metaspace

[Andrew Haley]

Another jtreg bug fix.  We had the code to do this for more than a year, but
it had never been tested and was nonsense.

Andrew.



# HG changeset patch
# User aph
# Date 1386954641 0
# Node ID 9d35c95768d0535479a54bcbac567aee9f091a0c
# Parent  3c620760454c2c4ea1f871d178e7ca8700bf92d3
Generate the self-patching vtable methods for shared metaspaces.

diff -r 3c620760454c -r 9d35c95768d0 src/cpu/aarch64/vm/metaspaceShared_aarch64.cpp
--- a/src/cpu/aarch64/vm/metaspaceShared_aarch64.cpp	Wed Dec 11 09:06:48 2013 +0000
+++ b/src/cpu/aarch64/vm/metaspaceShared_aarch64.cpp	Fri Dec 13 17:10:41 2013 +0000
@@ -76,6 +76,9 @@
     for (int j = 0; j < num_virtuals; ++j) {
       dummy_vtable[num_virtuals * i + j] = (void*)masm->pc();

+      // We're called directly from C code.
+      __ c_stub_prolog(8, 0, MacroAssembler::ret_type_integral);
+
       // Load rscratch1 with a value indicating vtable/offset pair.
       // -- bits[ 7..0]  (8 bits) which virtual method in table?
       // -- bits[12..8]  (5 bits) which virtual method table?
@@ -87,29 +90,17 @@

   __ bind(common_code);

-  // Expecting to be called with "thiscall" convections -- the arguments
-  // are on the stack and the "this" pointer is in c_rarg0. In addition, rscratch1
-  // was set (above) to the offset of the method in the table.
-
-  __ push(c_rarg1);                     // save & free register
-  __ push(c_rarg0);                     // save "this"
-  __ mov(c_rarg0, rscratch1);
-  __ lsr(c_rarg0, c_rarg0, 8);          // isolate vtable identifier.
-  __ lsl(c_rarg0, c_rarg0, LogBytesPerWord);
-  __ lea(c_rarg1, (address)vtbl_list);  // ptr to correct vtable list.
-  __ add(c_rarg1, c_rarg1, c_rarg0);    // ptr to list entry.
-  __ ldr(c_rarg1, Address(c_rarg1, 0)); // get correct vtable address.
-  __ pop(c_rarg0);                      // restore "this"
-  __ str(c_rarg1, Address(c_rarg0, 0)); // update vtable pointer.
-
-  __ andr(rscratch1, rscratch1, 0x00ff); // isolate vtable method index
-  __ lsl(rscratch1, rscratch1, LogBytesPerWord);
-  __ add(rscratch1, rscratch1, c_rarg1); // address of real method pointer.
-  __ pop(c_rarg1);                       // restore register.
-  __ ldr(rscratch1, Address(rscratch1, 0)); // get real method pointer.
-  __ br(rscratch1);                         // jump to the real method.
-
-  __ flush();
+  Register tmp0 = r10, tmp1 = r11;       // AAPCS64 temporary registers
+  __ enter();
+  __ lsr(tmp0, rscratch1, 8);            // isolate vtable identifier.
+  __ lea(tmp1, (address)vtbl_list);      // address of list of vtable pointers.
+  __ ldr(tmp1, Address(tmp1, tmp0, Address::lsl(LogBytesPerWord))); // get correct vtable pointer.
+  __ str(tmp1, Address(c_rarg0));        // update vtable pointer in obj.
+  __ add(rscratch1, tmp1, rscratch1, ext::uxtb, LogBytesPerWord); // address of real method pointer.
+  __ ldr(rscratch1, Address(rscratch1)); // get real method pointer.
+  __ blrt(rscratch1, 8, 0, 1);           // jump to the real method.
+  __ leave();
+  __ ret(lr);

   *mc_top = (char*)__ pc();
 }
diff -r 3c620760454c -r 9d35c95768d0 src/share/vm/runtime/globals.hpp
--- a/src/share/vm/runtime/globals.hpp	Wed Dec 11 09:06:48 2013 +0000
+++ b/src/share/vm/runtime/globals.hpp	Fri Dec 13 17:10:41 2013 +0000
@@ -3677,7 +3677,7 @@
   product(uintx, SharedMiscDataSize,    NOT_LP64(2*M) LP64_ONLY(4*M),       \
           "Size of the shared miscellaneous data area (in bytes)")          \
                                                                             \
-  product(uintx, SharedMiscCodeSize,    120*K,                              \
+  product(uintx, SharedMiscCodeSize,    192*K,                              \
           "Size of the shared miscellaneous code area (in bytes)")          \
                                                                             \
   product(uintx, SharedBaseAddress, LP64_ONLY(32*G)                         \