8329331: Intrinsify Unsafe::setMemory

src/hotspot/cpu/x86/stubGenerator_x86_64_arraycopy.cpp

@@ -2585,6 +2585,7 @@ address StubGenerator::generate_unsafe_setmemory(const char *name,
   __ align(CodeEntryAlignment);
   StubCodeMark mark(this, "StubRoutines", name);
   address start = __ pc();
+  __ enter();   // required for proper stackwalking of RuntimeStub frame
 
   assert(unsafe_byte_fill != nullptr, "Invalid call");
 
@@ -2594,34 +2595,25 @@ address StubGenerator::generate_unsafe_setmemory(const char *name,
   {
     Label L_exit, L_fillQuadwords, L_fillDwords, L_fillBytes;
 
-    // setup_arg_regs only has an effect for Windows
-    // Windows argument registers are moved into Linux ABI-defined registers
-    // r9 and r10 are used to save rsi and rdi and are therefore unavailable
-    // as scratch registers for the routine.
-    setup_arg_regs(3);
-
-    const Register dest = rdi;
-    const Register size = rsi;
+    const Register dest = c_rarg0;
+    const Register size = c_rarg1;
+    const Register byteVal = c_rarg2;
     const Register wide_value = rax;
-    const Register rScratch1 = rcx;
+    const Register rScratch1 = r10;
 
     //     fill_to_memory_atomic(unsigned char*, unsigned long, unsigned char)
 
     __ testq(size, size);
     __ jcc(Assembler::zero, L_exit);
 
-    {
-      const Register byteVal = rdx;
-
-      // Propagate byte to full Register
-      __ movzbl(rScratch1, byteVal);
-      __ mov64(wide_value, 0x0101010101010101);
-      __ imulq(wide_value, rScratch1);
+    // Propagate byte to full Register
+    __ movzbl(rScratch1, byteVal);
+    __ mov64(wide_value, 0x0101010101010101);
+    __ imulq(wide_value, rScratch1);
 
-      // Check for pointer & size alignment
-      __ movq(rScratch1, dest);
-      __ orq(rScratch1, size);
-    }
+    // Check for pointer & size alignment
+    __ movq(rScratch1, dest);
+    __ orq(rScratch1, size);
 
     __ testb(rScratch1, 7);
     __ jcc(Assembler::equal, L_fillQuadwords);
@@ -2658,7 +2650,7 @@ address StubGenerator::generate_unsafe_setmemory(const char *name,
     }
     __ BIND(L_exit);
 
-    restore_arg_regs();
+    __ leave();   // required for proper stackwalking of RuntimeStub frame
     __ ret(0);
 
     __ BIND(L_fillDwords);
@@ -2676,22 +2668,11 @@ address StubGenerator::generate_unsafe_setmemory(const char *name,
     __ jmp(L_exit);
 
     __ BIND(L_fillBytes);
-    {
-      const Register byteVal = rdx;
-#ifdef _WIN32
-      __ movq(rcx, rdi); // Restore c_rarg*
-      __ movq(r8, rdx);
-      __ movq(rdx, rsi);
-      restore_arg_regs();
-#endif
-      // rax has expanded byte value
-      __ movq(c_rarg2, rax);
-
-      // Set up for tail call to previously generated byte fill routine
-      // Parameter order is (ptr, byteVal, size)
-      __ xchgq(c_rarg1, c_rarg2);
-      __ jump(RuntimeAddress(unsafe_byte_fill));
-    }
+    // Set up for tail call to previously generated byte fill routine
+    // Parameter order is (ptr, byteVal, size)
+    __ xchgq(c_rarg1, c_rarg2);
+    __ pop(rbp);    // Clear effect of enter()
+    __ jump(RuntimeAddress(unsafe_byte_fill));
   }
 
   return start;