Bug 567707 - Crash in [@ nsThread::ProcessNextEvent] on x64 build with VC10 + --enable-optimize. r=timeless

xpcom/reflect/xptcall/src/md/win32/xptcinvoke_asm_x86_64.asm

@@ -46,106 +46,90 @@ extrn invoke_copy_to_stack:PROC
 
 XPTC__InvokebyIndex PROC FRAME
 
-   ;
    ; store register parameters
-   ;
 
     mov     qword ptr [rsp+32], r9        ; params
     mov     dword ptr [rsp+24], r8d       ; paramCount
     mov     dword ptr [rsp+16], edx       ; methodIndex
     mov     qword ptr [rsp+8], rcx        ; that
 
-    ;
-    ; store RBX/RBP register for backup
-    ;
-
-    mov     qword ptr [rsp-16], rbp
-
+    push    rbp
+    .PUSHREG rbp
     mov     rbp, rsp            ; store current RSP to RBP
     .SETFRAME rbp, 0
     .ENDPROLOG
 
     sub     rsp, 32
 
-    ;
     ; maybe we don't have any parameters to copy
-    ;
 
     test    r8d, r8d
     jz      noparams
 
     ;
-    ; make space for 1st parameter
+    ; Build stack for stdcall
+    ;
+
+    ; 1st parameter is space for parameters
 
     mov     eax, r8d
-    and     eax, 1              ; AMD64 must be alignment to 16 bytes
-    add     eax, r8d
+    or      eax, 1
     shl     rax, 3              ; *= 8
     sub     rsp, rax
     mov     rcx, rsp
 
-    ;
     ; 2nd parameter is parameter count
-    ;
 
     mov     edx, r8d
 
-    ;
     ; 3rd parameter is params
-    ;
 
     mov     r8, r9
 
-    sub     rsp, 32
-
+    sub     rsp, 40
     call    invoke_copy_to_stack ; rcx = d
                                  ; edx = paramCount
                                  ; r8  = s
-
     add     rsp, 32
 
+    ; Current stack is the following.
     ;
-    ; Build parameters
+    ;  0h: [space (for this)]
+    ;  8h: [1st parameter]
+    ; 10h: [2nd parameter]
+    ; 18h: [3rd parameter]
+    ; 20h: [4th parameter]
+    ; ...
     ;
+    ; On Win64 ABI, the first 4 parameters are passed using registers,
+    ; and others are on stack. 
 
-    mov     rdx, qword ptr [rsp] ; 1st parameter
-    movsd   xmm1, qword ptr [rsp] ; for double
+    ; 1st, 2nd and 3rd arguments are passed via registers
 
-    mov     r8, qword ptr [rsp+8] ; 2nd parameter
-    movsd   xmm2, qword ptr [rsp+8] ; for double
+    mov     rdx, qword ptr [rsp+8] ; 1st parameter
+    movsd   xmm1, qword ptr [rsp+8] ; for double
 
-    mov     r9, qword ptr [rsp+16] ; 3rd parameter
-    movsd   xmm3, qword ptr [rsp+16] ; for double
+    mov     r8, qword ptr [rsp+16] ; 2nd parameter
+    movsd   xmm2, qword ptr [rsp+16] ; for double
 
-    ;
-    ; 1st parameter (this)
-    ;
+    mov     r9, qword ptr [rsp+24] ; 3rd parameter
+    movsd   xmm3, qword ptr [rsp+24] ; for double
 
-    mov     rcx, qword ptr [rbp+8] ; that
+    ; rcx register is this
+
+    mov     rcx, qword ptr [rbp+8+8] ; that
 
 noparams:
 
-    ;
     ; calculate call address
-    ;
 
     mov     r11, qword ptr [rcx]
-    mov     eax, dword ptr [rbp+16] ; methodIndex
-
-    ;
-    ; Now current stack has parameter list
-    ; But, since callee function backups parameters, make space into stack.
-
-    sub     rsp, 8
+    mov     eax, dword ptr [rbp+16+8] ; methodIndex
 
     call    qword ptr [r11+rax*8]      ; stdcall, i.e. callee cleans up stack.
 
-    ;
-    ; restore registers
-    ;
-
     mov     rsp, rbp
-    mov     rbp, qword ptr [rsp-16]
+    pop     rbp
 
     ret