patch 9.0.2186: LTCG compile error ARM64 for write_chars
Problem: LTCG compile error on Win/ARM64 for `write_chars()`
Solution: Explicitly initialise the storage to use data rather than BSS
(Saleem Abdulrasool)
win32: add a workaround for a LTCG issue on Windows ARM64
It appears that the implicit initialisation which would push `g_coords`
into BSS causes an aliasing issue with LTCG on ARM64. By explicitly
initialising the value, we use usual data storage but prevent the
aliasing. This allows the console version of VIM to run on Windows
ARM64 again.
fixes: #13453
closes: #13775
Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/os_win32.c b/src/os_win32.c
index 2bf0fe7..e5cfac7 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -156,7 +156,10 @@
// Win32 Screen buffer,coordinate,console I/O information
static SMALL_RECT g_srScrollRegion;
-static COORD g_coord; // 0-based, but external coords are 1-based
+// This is explicitly initialised to work around a LTCG issue on Windows ARM64
+// (at least of 19.39.33321). This pushes this into the `.data` rather than
+// `.bss` which corrects code generation in `write_chars` (#13453).
+static COORD g_coord = {0, 0}; // 0-based, but external coords are 1-based
// The attribute of the screen when the editor was started
static WORD g_attrDefault = 7; // lightgray text on black background