[PATCH v2 0/1] MR3587: mshtml: Define skip_prefix without using a magic number.

[Alex Henrie (＠alexhenrie)]

--
  v2: mshtml: Define skip_prefix without using a magic number.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/3587

[PATCH v2 1/1] mshtml: Define skip_prefix without using a magic number.

[Alex Henrie]

From: Alex Henrie <alexhenrie24(a)gmail.com>

---
 dlls/mshtml/omnavigator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/mshtml/omnavigator.c b/dlls/mshtml/omnavigator.c
index 646017aee9e..cfabd22cf29 100644
--- a/dlls/mshtml/omnavigator.c
+++ b/dlls/mshtml/omnavigator.c
@@ -1261,7 +1261,7 @@ static HRESULT WINAPI OmNavigator_get_appVersion(IOmNavigator *iface, BSTR *p)
     WCHAR *user_agent;
     unsigned len;
     HRESULT hres;
-    const unsigned skip_prefix = 8; /* strlen("Mozilla/") */
+    const unsigned skip_prefix = strlen("Mozilla/");
 
     TRACE("(%p)->(%p)\n", This, p);
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/3587

[Alex Henrie (＠alexhenrie)]

On Thu Aug 17 15:54:00 2023 +0000, Gabriel Ivăncescu wrote:
> In terms of optimization, as long as the address isn't taken, a const
> local variable will literally get replaced by the direct constant, as if
> using a #define macro or an enum, how is static better?
> The compiler actually has to do *more* work to optimize out a static
> constant like this, since it has to actually remove the variable
> (because it's not addressed from anything via its address and not
> visible outside the compilation unit, so it can be removed, but still
> that's an extra effort it has to do).
> const local variables aren't even allocated as variables when
> optimizing. Even if they did, it's because they're caching some
> expensive calculation, which is actually good.
> static const makes sense when you want to have one pre-allocated
> instance of the variable, when you need to actually read it via its
> address. This is not the case here.
> All good points, thanks for the explanation. I've pushed a new patch that uses strlen. The function call is optimized out on GCC and Clang, so the final machine code is identical. Still waiting to hear Jacek's opinion.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/3587#note_42673

[PATCH v2 0/1] MR3587: mshtml: Define skip_prefix without using a magic number. - approved

[Jacek Caban (＠jacek)]

This merge request was approved by Jacek Caban.
-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/3587