msvcrt: Simplify stack layout in __crtCapturePreviousContext().

Signed-off-by: Alexandre Julliard <julliard@winehq.org>

msvcrt: Simplify stack layout in __crtCapturePreviousContext().
ed6aa17d · Alexandre Julliard · 451c8592 · ed6aa17d
Commit ed6aa17d authored Aug 21, 2019 by Alexandre Julliard
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Showing with 8 additions and 13 deletions

except_x86_64.c dlls/msvcrt/except_x86_64.c +8 -13

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--- a/dlls/msvcrt/except_x86_64.c
+++ b/dlls/msvcrt/except_x86_64.c
@@ -732,9 +732,6 @@ void __cdecl get_prev_context(CONTEXT *ctx, DWORD64 rip)

    TRACE("(%p)\n", ctx);

-    ctx->Rip = rip;
-    ctx->Rsp += 3*8; /* Rip, Rcx, return address */
-
    rf = RtlLookupFunctionEntry(ctx->Rip, &image_base, NULL);
    if(!rf) {
        FIXME("RtlLookupFunctionEntry failed\n");
@@ -746,16 +743,14 @@ void __cdecl get_prev_context(CONTEXT *ctx, DWORD64 rip)
 }

 __ASM_GLOBAL_FUNC( __crtCapturePreviousContext,
-        "pushq (%rsp)\n\t" /* save Rip */
-        __ASM_CFI(".cfi_adjust_cfa_offset 8\n\t")
-        "pushq %rcx\n\t"
-        __ASM_CFI(".cfi_adjust_cfa_offset 8\n\t")
-        "call " __ASM_NAME("RtlCaptureContext") "\n\t"
-        "popq %rcx\n\t"
-        __ASM_CFI(".cfi_adjust_cfa_offset -8\n\t")
-        "popq %rdx\n\t"
-        __ASM_CFI(".cfi_adjust_cfa_offset -8\n\t")
-        "jmp " __ASM_NAME("get_prev_context") );
+                   "movq %rcx,8(%rsp)\n\t"
+                   "call " __ASM_NAME("RtlCaptureContext") "\n\t"
+                   "movq 8(%rsp),%rcx\n\t"     /* context */
+                   "leaq 8(%rsp),%rax\n\t"
+                   "movq %rax,0x98(%rcx)\n\t"  /* context->Rsp */
+                   "movq (%rsp),%rax\n\t"
+                   "movq %rax,0xf8(%rcx)\n\t"  /* context->Rip */
+                   "jmp " __ASM_NAME("get_prev_context") )
 #endif

 #endif  /* __x86_64__ */