[PATCH 0/2] MR4088: Fix WineDbg backtrace on macOS.

[eric pouech (＠epo)]

Fix winedbg's backtrace command on macos for a 64 bit debugger on a
32 bit debuggee.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/4088

[PATCH 1/2] winedbg: Set first LDT entry value as ntdll does.

[Eric Pouech]

From: Eric Pouech <epouech(a)codeweavers.com>

Signed-off-by: Eric Pouech <epouech(a)codeweavers.com>
---
 programs/winedbg/be_i386.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/programs/winedbg/be_i386.c b/programs/winedbg/be_i386.c
index 503a182641d..9f22dd5f3d4 100644
--- a/programs/winedbg/be_i386.c
+++ b/programs/winedbg/be_i386.c
@@ -30,13 +30,15 @@ WINE_DEFAULT_DEBUG_CHANNEL(winedbg);
 
 #define IS_VM86_MODE(ctx) (ctx->EFlags & V86_FLAG)
 
+static const unsigned first_ldt_entry = 32;
+
 static ADDRESS_MODE get_selector_type(HANDLE hThread, const WOW64_CONTEXT *ctx, WORD sel)
 {
     LDT_ENTRY	le;
 
     if (IS_VM86_MODE(ctx)) return AddrModeReal;
     /* null or system selector */
-    if (!(sel & 4) || ((sel >> 3) < 17)) return AddrModeFlat;
+    if (!(sel & 4) || ((sel >> 3) < first_ldt_entry)) return AddrModeFlat;
     if (dbg_curr_process->process_io->get_selector(hThread, sel, &le))
         return le.HighWord.Bits.Default_Big ? AddrMode1632 : AddrMode1616;
     /* selector doesn't exist */
@@ -52,7 +54,7 @@ static void* be_i386_linearize(HANDLE hThread, const ADDRESS64* addr)
     case AddrModeReal:
         return (void*)((DWORD_PTR)(LOWORD(addr->Segment) << 4) + (DWORD_PTR)addr->Offset);
     case AddrMode1632:
-        if (!(addr->Segment & 4) || ((addr->Segment >> 3) < 17))
+        if (!(addr->Segment & 4) || ((addr->Segment >> 3) < first_ldt_entry))
             return (void*)(DWORD_PTR)addr->Offset;
         /* fall through */
     case AddrMode1616:
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/4088

[PATCH 2/2] winedbg: Correctly read LDT entries for wow64 debuggee.

[Eric Pouech]

From: Eric Pouech <epouech(a)codeweavers.com>

This mostly matters for Mac as segment CS is handled as a real LDT
entry.

Signed-off-by: Eric Pouech <epouech(a)codeweavers.com>
---
 programs/winedbg/be_i386.c    |  7 ++++++-
 programs/winedbg/tgt_active.c | 10 ++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/programs/winedbg/be_i386.c b/programs/winedbg/be_i386.c
index 9f22dd5f3d4..1bac5f382b2 100644
--- a/programs/winedbg/be_i386.c
+++ b/programs/winedbg/be_i386.c
@@ -40,7 +40,12 @@ static ADDRESS_MODE get_selector_type(HANDLE hThread, const WOW64_CONTEXT *ctx,
     /* null or system selector */
     if (!(sel & 4) || ((sel >> 3) < first_ldt_entry)) return AddrModeFlat;
     if (dbg_curr_process->process_io->get_selector(hThread, sel, &le))
-        return le.HighWord.Bits.Default_Big ? AddrMode1632 : AddrMode1616;
+    {
+        ULONG base = (le.HighWord.Bits.BaseHi << 24) + (le.HighWord.Bits.BaseMid << 16) + le.BaseLow;
+        if (le.HighWord.Bits.Default_Big)
+            return base == 0 ? AddrModeFlat : AddrMode1632;
+        return AddrMode1616;
+    }
     /* selector doesn't exist */
     return -1;
 }
diff --git a/programs/winedbg/tgt_active.c b/programs/winedbg/tgt_active.c
index 5ac9a4d1229..17578857133 100644
--- a/programs/winedbg/tgt_active.c
+++ b/programs/winedbg/tgt_active.c
@@ -1067,7 +1067,17 @@ static BOOL tgt_process_active_write(HANDLE hProcess, void* addr,
 
 static BOOL tgt_process_active_get_selector(HANDLE hThread, DWORD sel, LDT_ENTRY* le)
 {
+#ifdef _WIN64
+    THREAD_DESCRIPTOR_INFORMATION desc = { .Selector = sel };
+    ULONG retlen;
+
+    if (RtlWow64GetThreadSelectorEntry( hThread, &desc, sizeof(desc), &retlen ))
+        return FALSE;
+    *le = desc.Entry;
+    return TRUE;
+#else
     return GetThreadSelectorEntry( hThread, sel, le );
+#endif
 }
 
 static struct be_process_io be_process_active_io =
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/4088

[eric pouech (＠epo)]

all pipeline failures are present before the MR

domdoc: https://bugs.winehq.org/show_bug.cgi?id=55720 

filtergraph: https://bugs.winehq.org/show_bug.cgi?id=55758 

d2d1: https://bugs.winehq.org/show_bug.cgi?id=55765

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/4088#note_48626