nterp: Address old x86-64 comments.

Follow-up to
    https://android-review.googlesource.com/1185416 ,
    https://android-review.googlesource.com/1180627 .

Test: testrunner.py --host --interpreter
Change-Id: I4ee8825593cf11d673fcaf8e1172d00405cc7abc

2 files changed, 47 insertions, 39 deletions

diff --git a/runtime/interpreter/mterp/x86_64ng/main.S b/runtime/interpreter/mterp/x86_64ng/main.S
index 4eaf95e549..aeacec4daf 100644
--- a/runtime/interpreter/mterp/x86_64ng/main.S
+++ b/runtime/interpreter/mterp/x86_64ng/main.S
@@ -606,19 +606,19 @@ END_FUNCTION \name
     je 2f
     cmpb MACRO_LITERAL(70), %al             // if (al == 'F') goto FOUND_FLOAT
     je 3f
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     //  Handle extra argument in arg array taken by a long.
     cmpb MACRO_LITERAL(74), %al   // if (al != 'J') goto LOOP
     jne 1b
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 1b                        // goto LOOP
 2:  // FOUND_DOUBLE
-    movsd REG_VAR(xmm_reg),(REG_VAR(fp), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(8), REG_VAR(arg_index)
+    movsd REG_VAR(xmm_reg),(REG_VAR(fp), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(2), REG_VAR(arg_index)
     jmp 4f
 3:  // FOUND_FLOAT
-    movss REG_VAR(xmm_reg), (REG_VAR(fp), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    movss REG_VAR(xmm_reg), (REG_VAR(fp), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
 4:
 .endm
 
@@ -638,22 +638,22 @@ END_FUNCTION \name
     je 3f
     cmpb MACRO_LITERAL(68), %al   // if (al == 'D') goto SKIP_DOUBLE
     je 4f
-    movl REG_VAR(gpr_reg32), (REG_VAR(regs), REG_VAR(arg_index), 1)
+    movl REG_VAR(gpr_reg32), (REG_VAR(regs), REG_VAR(arg_index), 4)
     cmpb MACRO_LITERAL(76), %al   // if (al != 'L') goto NOT_REFERENCE
     jne 6f
-    movl REG_VAR(gpr_reg32), (REG_VAR(refs), REG_VAR(arg_index), 1)
+    movl REG_VAR(gpr_reg32), (REG_VAR(refs), REG_VAR(arg_index), 4)
 6:  // NOT_REFERENCE
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 5f
 2:  // FOUND_LONG
-    movq REG_VAR(gpr_reg64), (REG_VAR(regs), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(8), REG_VAR(arg_index)
+    movq REG_VAR(gpr_reg64), (REG_VAR(regs), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(2), REG_VAR(arg_index)
     jmp 5f
 3:  // SKIP_FLOAT
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 1b
 4:  // SKIP_DOUBLE
-    addq MACRO_LITERAL(8), REG_VAR(arg_index)
+    addq MACRO_LITERAL(2), REG_VAR(arg_index)
     jmp 1b
 5:
 .endm
@@ -676,21 +676,21 @@ END_FUNCTION \name
     je 2f
     cmpb MACRO_LITERAL(70), %al             // if (al == 'F') goto FOUND_FLOAT
     je 3f
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     //  Handle extra argument in arg array taken by a long.
     cmpb MACRO_LITERAL(74), %al   // if (al != 'J') goto LOOP
     jne 1b
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 1b                        // goto LOOP
 2:  // FOUND_DOUBLE
-    movq OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 1), %rax
-    movq %rax, (REG_VAR(regs), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(8), REG_VAR(arg_index)
+    movq OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 4), %rax
+    movq %rax, (REG_VAR(regs), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(2), REG_VAR(arg_index)
     jmp 1b
 3:  // FOUND_FLOAT
-    movl OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 1), %eax
-    movl %eax, (REG_VAR(regs), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    movl OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 4), %eax
+    movl %eax, (REG_VAR(regs), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 1b
 .endm
 
@@ -712,26 +712,26 @@ END_FUNCTION \name
     je 3f
     cmpb MACRO_LITERAL(68), %al   // if (al == 'D') goto SKIP_DOUBLE
     je 4f
-    movl OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 1), %eax
-    movl %eax, (REG_VAR(regs), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    movl OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 4), %eax
+    movl %eax, (REG_VAR(regs), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 1b
 6:  // FOUND_REFERENCE
-    movl OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 1), %eax
-    movl %eax, (REG_VAR(regs), REG_VAR(arg_index), 1)
-    movl %eax, (REG_VAR(refs), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    movl OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 4), %eax
+    movl %eax, (REG_VAR(regs), REG_VAR(arg_index), 4)
+    movl %eax, (REG_VAR(refs), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 1b
 2:  // FOUND_LONG
-    movq OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 1), %rax
-    movq %rax, (REG_VAR(regs), REG_VAR(arg_index), 1)
-    addq MACRO_LITERAL(8), REG_VAR(arg_index)
+    movq OFFSET_TO_FIRST_ARGUMENT_IN_STACK(REG_VAR(stack_ptr), REG_VAR(arg_index), 4), %rax
+    movq %rax, (REG_VAR(regs), REG_VAR(arg_index), 4)
+    addq MACRO_LITERAL(2), REG_VAR(arg_index)
     jmp 1b
 3:  // SKIP_FLOAT
-    addq MACRO_LITERAL(4), REG_VAR(arg_index)
+    addq MACRO_LITERAL(1), REG_VAR(arg_index)
     jmp 1b
 4:  // SKIP_DOUBLE
-    addq MACRO_LITERAL(8), REG_VAR(arg_index)
+    addq MACRO_LITERAL(2), REG_VAR(arg_index)
     jmp 1b
 .endm
 
diff --git a/runtime/oat_quick_method_header.cc b/runtime/oat_quick_method_header.cc
index ebb868b11f..bbc3bfaf32 100644
--- a/runtime/oat_quick_method_header.cc
+++ b/runtime/oat_quick_method_header.cc
@@ -16,6 +16,7 @@
 
 #include "oat_quick_method_header.h"
 
+#include "arch/instruction_set.h"
 #include "art_method.h"
 #include "dex/dex_file_types.h"
 #include "interpreter/interpreter_mterp_impl.h"
@@ -88,12 +89,19 @@ uintptr_t OatQuickMethodHeader::ToNativeQuickPc(ArtMethod* method,
   return UINTPTR_MAX;
 }
 
-OatQuickMethodHeader* OatQuickMethodHeader::NterpMethodHeader =
-    (interpreter::IsNterpSupported()
-        ? reinterpret_cast<OatQuickMethodHeader*>(
-              reinterpret_cast<uintptr_t>(interpreter::GetNterpEntryPoint()) -
-                  sizeof(OatQuickMethodHeader))
-        : nullptr);
+static inline OatQuickMethodHeader* GetNterpMethodHeader() {
+  if (!interpreter::IsNterpSupported()) {
+    return nullptr;
+  }
+  uintptr_t nterp_entrypoint = reinterpret_cast<uintptr_t>(interpreter::GetNterpEntryPoint());
+  uintptr_t nterp_code_pointer = (kRuntimeISA == InstructionSet::kArm)
+      // Remove the Thumb mode bit if present on ARM.
+      ? nterp_entrypoint & ~static_cast<uintptr_t>(1)
+      : nterp_entrypoint;
+  return reinterpret_cast<OatQuickMethodHeader*>(nterp_code_pointer - sizeof(OatQuickMethodHeader));
+}
+
+OatQuickMethodHeader* OatQuickMethodHeader::NterpMethodHeader = GetNterpMethodHeader();
 
 bool OatQuickMethodHeader::IsNterpMethodHeader() const {
   return interpreter::IsNterpSupported() ? (this == NterpMethodHeader) : false;