ntdll: Fix more corner cases for arm64 packed info unwinding.

Make sure to restore sp from fp for CR == 3. Fix unwinding of partial prologues/epilogues - the previous logic had an off-by-one for the pos/skip handling; fix a few more corner cases with odd number of saved registers. Functions with the H flag set (saving x0-x7 on the stack) should be considred having 4 nops (for the instructions saving the registers) in the prologue for unwind purposes. When unwinding through a partial epilogue, the same 4 nops should also be considered to be there (even though no sane epilogue would restore the registers there) based on how windows handles partial epilogue unwinding in those cases. Uncomment prologue/epilogue cases in an existing test and add tests for many more cases. Signed-off-by: Martin Storsjo <martin@martin.st> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

ntdll: Fix more corner cases for arm64 packed info unwinding.
3395ee36 · Martin Storsjo · Alexandre Julliard · 578aae07 · 3395ee36 · 3395ee36
Commit 3395ee36 authored Sep 07, 2020 by Martin Storsjo Committed by Alexandre Julliard Sep 07, 2020
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Showing with 24 additions and 17 deletions

signal_arm64.c dlls/ntdll/signal_arm64.c +24 -17

exception.c dlls/ntdll/tests/exception.c +0 -0

No files found.
--- a/dlls/ntdll/signal_arm64.c
+++ b/dlls/ntdll/signal_arm64.c
@@ -708,6 +708,7 @@ static void *unwind_packed_data( ULONG_PTR base, ULONG_PTR pc, RUNTIME_FUNCTION 
            switch (func->u.s.CR)
            {
            case 3:
+                len++; /* mov x29,sp */
                len++; /* stp x29,lr,[sp,0] */
                if (local_size <= 512) break;
                /* fall through */
@@ -717,9 +718,10 @@ static void *unwind_packed_data( ULONG_PTR base, ULONG_PTR pc, RUNTIME_FUNCTION 
                if (local_size > 4088) len++;  /* sub sp,sp,#4088 */
                break;
            }
-            if (offset < len + 4 * func->u.s.H)  /* prolog */
+            len += 4 * func->u.s.H;
+            if (offset < len)  /* prolog */
            {
-                skip = len + 4 * func->u.s.H - offset;
+                skip = len - offset;
            }
            else if (offset >= func->u.s.FunctionLength - (len + 1))  /* epilog */
            {
@@ -733,6 +735,7 @@ static void *unwind_packed_data( ULONG_PTR base, ULONG_PTR pc, RUNTIME_FUNCTION 
        if (func->u.s.CR == 3)
        {
            DWORD64 *fp = (DWORD64 *) context->u.s.Fp; /* u.X[29] */
+            context->Sp = context->u.s.Fp;
            context->u.X[29] = fp[0];
            context->u.X[30] = fp[1];
        }
@@ -748,34 +751,36 @@ static void *unwind_packed_data( ULONG_PTR base, ULONG_PTR pc, RUNTIME_FUNCTION 
        switch (func->u.s.CR)
        {
        case 3:
+            /* mov x29,sp */
+            if (pos++ >= skip) context->Sp = context->u.s.Fp;
            if (local_size <= 512)
            {
                /* stp x29,lr,[sp,-#local_size]! */
-                if (pos++ > skip) restore_regs( 29, 2, -local_size_regs, context, ptrs );
+                if (pos++ >= skip) restore_regs( 29, 2, -local_size_regs, context, ptrs );
                break;
            }
            /* stp x29,lr,[sp,0] */
-            if (pos++ > skip) restore_regs( 29, 2, 0, context, ptrs );
+            if (pos++ >= skip) restore_regs( 29, 2, 0, context, ptrs );
            /* fall through */
        case 0:
        case 1:
            if (!local_size) break;
            /* sub sp,sp,#local_size */
-            if (pos++ > skip) context->Sp += (local_size - 1) % 4088 + 1;
-            if (local_size > 4088 && pos++ > skip) context->Sp += 4088;
+            if (pos++ >= skip) context->Sp += (local_size - 1) % 4088 + 1;
+            if (local_size > 4088 && pos++ >= skip) context->Sp += 4088;
            break;
        }

-        if (func->u.s.H && offset < len + 4) pos += 4;
+        if (func->u.s.H) pos += 4;

        if (fp_size)
        {
-            if (func->u.s.RegF % 2 == 0 && pos++ > skip)
+            if (func->u.s.RegF % 2 == 0 && pos++ >= skip)
                /* str d%u,[sp,#fp_size] */
                restore_fpregs( 8 + func->u.s.RegF, 1, int_regs + fp_regs - 1, context, ptrs );
-            for (i = func->u.s.RegF / 2 - 1; i >= 0; i--)
+            for (i = (func->u.s.RegF + 1) / 2 - 1; i >= 0; i--)
            {
-                if (pos++ <= skip) continue;
+                if (pos++ < skip) continue;
                if (!i && !int_size)
                     /* stp d8,d9,[sp,-#regsave]! */
                    restore_fpregs( 8, 2, -saved_regs, context, ptrs );
@@ -785,9 +790,9 @@ static void *unwind_packed_data( ULONG_PTR base, ULONG_PTR pc, RUNTIME_FUNCTION 
            }
        }

-        if (pos++ > skip)
+        if (func->u.s.RegI % 2)
        {
-            if (func->u.s.RegI % 2)
+            if (pos++ >= skip)
            {
                /* stp xn,lr,[sp,#offset] */
                if (func->u.s.CR == 1) restore_regs( 30, 1, int_regs - 1, context, ptrs );
@@ -796,14 +801,16 @@ static void *unwind_packed_data( ULONG_PTR base, ULONG_PTR pc, RUNTIME_FUNCTION 
                              (func->u.s.RegI > 1) ? func->u.s.RegI - 1 : -saved_regs,
                              context, ptrs );
            }
-            else if (func->u.s.CR == 1)
-                /* str lr,[sp,#offset] */
-                restore_regs( 30, 1, func->u.s.RegI ? int_regs - 1 : -saved_regs, context, ptrs );
+        }
+        else if (func->u.s.CR == 1)
+        {
+            /* str lr,[sp,#offset] */
+            if (pos++ >= skip) restore_regs( 30, 1, func->u.s.RegI ? int_regs - 1 : -saved_regs, context, ptrs );
        }

-        for (i = func->u.s.RegI / 2 - 1; i >= 0; i--)
+        for (i = func->u.s.RegI/ 2 - 1; i >= 0; i--)
        {
-            if (pos++ <= skip) continue;
+            if (pos++ < skip) continue;
            if (i)
                /* stp xn,xn+1,[sp,#offset] */
                restore_regs( 19 + 2 * i, 2, 2 * i, context, ptrs );

--- a/dlls/ntdll/tests/exception.c
+++ b/dlls/ntdll/tests/exception.c