Work in the direction of hard float quick ABIs.

Pass a shorty to ArtMethod::Invoke so that register setup can use it.
Document x86-64 ABI.
Add extra debug output for one JNI native method registration fails, namely a
dump of the Class and its dex file's location.
Add hack to get testing of OatMethod's without GC maps working in 64bit.

Change-Id: Ic06b68e18eac33637df2caf5e7e775ff95ae70f3
diff --git a/runtime/arch/x86/quick_entrypoints_x86.S b/runtime/arch/x86/quick_entrypoints_x86.S
index 9c3eb30..c76c6b2 100644
--- a/runtime/arch/x86/quick_entrypoints_x86.S
+++ b/runtime/arch/x86/quick_entrypoints_x86.S
@@ -251,7 +251,7 @@
      *   [sp + 12] = size of argument array in bytes
      *   [sp + 16] = (managed) thread pointer
      *   [sp + 20] = JValue* result
-     *   [sp + 24] = result type char
+     *   [sp + 24] = shorty
      */
 DEFINE_FUNCTION art_quick_invoke_stub
     PUSH ebp                      // save ebp
@@ -281,17 +281,20 @@
     POP ebx                       // pop ebx
     POP ebp                       // pop ebp
     mov 20(%esp), %ecx            // get result pointer
-    cmpl LITERAL(68), 24(%esp)    // test if result type char == 'D'
-    je return_double_quick
-    cmpl LITERAL(70), 24(%esp)    // test if result type char == 'F'
-    je return_float_quick
-    mov %eax, (%ecx)              // store the result
+    mov %eax, (%ecx)              // store the result assuming its a long, int or Object*
     mov %edx, 4(%ecx)             // store the other half of the result
+    mov 24(%esp), %edx            // get the shorty
+    cmpb LITERAL(68), (%edx)      // test if result type char == 'D'
+    je return_double_quick
+    cmpb LITERAL(70), (%edx)      // test if result type char == 'F'
+    je return_float_quick
     ret
 return_double_quick:
-return_float_quick:
     movsd %xmm0, (%ecx)           // store the floating point result
     ret
+return_float_quick:
+    movss %xmm0, (%ecx)           // store the floating point result
+    ret
 END_FUNCTION art_quick_invoke_stub
 
 MACRO3(NO_ARG_DOWNCALL, c_name, cxx_name, return_macro)