Changeset 98151 in vbox for trunk/src/VBox/Runtime/common/compiler/vcc/stack-vcc.asm

Timestamp:

Jan 20, 2023 9:16:34 AM (2 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

155324

Message:

IPRT/vcc: Split out the stack probing code (_chkstk) from stack-vcc.asm. bugref:10348 bugref:10261

File:

• trunk/src/VBox/Runtime/common/compiler/vcc/stack-vcc.asm (modified) (1 diff)

trunk/src/VBox/Runtime/common/compiler/vcc/stack-vcc.asm

@@ -124 +124 @@
 %endif
 
-
-
-;;
-; Probe stack to trigger guard faults, and for x86 to allocate stack space.
-;
-; @param    xAX     Frame size.
-; @uses     AMD64:  Probably nothing. EAX is certainly not supposed to change.
-;           x86:    ESP = ESP - EAX; EFLAGS, nothing else
-;
-ALIGNCODE(64)
-GLOBALNAME_RAW  __alloca_probe, __alloca_probe, function
-BEGINPROC_RAW   __chkstk
-        push    xBP
-        SEH64_PUSH_xBP
-        mov     xBP, xSP
-        SEH64_SET_FRAME_xBP 0
-        push    xAX
-        SEH64_PUSH_GREG xAX
-        push    xBX
-        SEH64_PUSH_GREG xBX
-        SEH64_END_PROLOGUE
-
-        ;
-        ; Adjust eax so we're relative to [xBP - xCB*2].
-        ;
-        sub     xAX, xCB * 4
-        jle     .touch_loop_done            ; jump if rax < xCB*4, very unlikely
-
-        ;
-        ; Subtract what's left of the current page from eax and only engage
-        ; the touch loop if (int)xAX > 0.
-        ;
-        lea     ebx, [ebp - xCB * 2]
-        and     ebx, PAGE_SIZE - 1
-        sub     xAX, xBX
-        jnl     .touch_loop                 ; jump if pages to touch.
-
-.touch_loop_done:
-        pop     xBX
-        pop     xAX
-        leave
-%ifndef RT_ARCH_X86
-        ret
-%else
-        ;
-        ; Do the stack space allocation and jump to the return location.
-        ;
-        sub     esp, eax
-        add     esp, 4
-        jmp     dword [esp + eax - 4]
-%endif
-
-        ;
-        ; The touch loop.
-        ;
-.touch_loop:
-        sub     xBX, PAGE_SIZE
-%if 1
-        mov     [xBP + xBX - xCB * 2], bl
-%else
-        or      byte [xBP + xBX - xCB * 2], 0   ; non-destructive variant...
-%endif
-        sub     xAX, PAGE_SIZE
-        jnl     .touch_loop
-        jmp     .touch_loop_done
-ENDPROC_RAW     __chkstk
-
-
-%ifdef RT_ARCH_X86
-;;
-; 8 and 16 byte aligned alloca w/ probing.
-;
-; This routine adjusts the allocation size so __chkstk will return a
-; correctly aligned allocation.
-;
-; @param    xAX     Unaligned allocation size.
-;
-%macro __alloc_probe_xxx 1
-ALIGNCODE(16)
-BEGINPROC_RAW   __alloca_probe_ %+ %1
-        push    ecx
-
-        ;
-        ; Calc the ESP address after the allocation and adjust EAX so that it
-        ; will be aligned as desired.
-        ;
-        lea     ecx, [esp + 8]
-        sub     ecx, eax
-        and     ecx, %1 - 1
-        add     eax, ecx
-        jc      .bad_alloc_size
-.continue:
-
-        pop     ecx
-        jmp     __alloca_probe
-
-.bad_alloc_size:
-  %ifdef RT_STRICT
-        int3
-  %endif
-        or      eax, 0xfffffff0
-        jmp     .continue
-ENDPROC_RAW     __alloca_probe_ %+ %1
-%endmacro
-
-__alloc_probe_xxx 16
-__alloc_probe_xxx 8
-%endif ; RT_ARCH_X86