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From: Laszlo Ersek <lersek@redhat.com>
To: edk2-devel-01 <edk2-devel@lists.01.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Cole Robinson <crobinso@redhat.com>,
	Liming Gao <liming.gao@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Yonghong Zhu <yonghong.zhu@intel.com>
Subject: [PATCH 1/3] BaseTools/header.makefile: add "-Wno-stringop-truncation"
Date: Fri,  2 Mar 2018 19:09:22 +0100	[thread overview]
Message-ID: <20180302180924.4312-2-lersek@redhat.com> (raw)
In-Reply-To: <20180302180924.4312-1-lersek@redhat.com>

gcc-8 (which is part of Fedora 28) enables the new warning
"-Wstringop-truncation" in "-Wall". This warning is documented in detail
at <https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html>; the
introduction says

> Warn for calls to bounded string manipulation functions such as strncat,
> strncpy, and stpncpy that may either truncate the copied string or leave
> the destination unchanged.

It breaks the BaseTools build with:

> EfiUtilityMsgs.c: In function 'PrintMessage':
> EfiUtilityMsgs.c:484:9: error: 'strncat' output may be truncated copying
> between 0 and 511 bytes from a string of length 511
> [-Werror=stringop-truncation]
>          strncat (Line, Line2, MAX_LINE_LEN - strlen (Line) - 1);
>          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> EfiUtilityMsgs.c:469:9: error: 'strncat' output may be truncated copying
> between 0 and 511 bytes from a string of length 511
> [-Werror=stringop-truncation]
>          strncat (Line, Line2, MAX_LINE_LEN - strlen (Line) - 1);
>          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> EfiUtilityMsgs.c:511:5: error: 'strncat' output may be truncated copying
> between 0 and 511 bytes from a string of length 511
> [-Werror=stringop-truncation]
>      strncat (Line, Line2, MAX_LINE_LEN - strlen (Line) - 1);
>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The right way to fix the warning would be to implement string concat with
snprintf(). However, Microsoft does not appear to support snprintf()
before VS2015
<https://stackoverflow.com/questions/2915672/snprintf-and-visual-studio-2010>,
so we just have to shut up the warning. The strncat() calls flagged above
are valid BTW.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Cole Robinson <crobinso@redhat.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 BaseTools/Source/C/Makefiles/header.makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/BaseTools/Source/C/Makefiles/header.makefile b/BaseTools/Source/C/Makefiles/header.makefile
index 0976973bdd7b..550f8b35bce2 100644
--- a/BaseTools/Source/C/Makefiles/header.makefile
+++ b/BaseTools/Source/C/Makefiles/header.makefile
@@ -71,9 +71,9 @@ INCLUDE = $(TOOL_INCLUDE) -I $(MAKEROOT) -I $(MAKEROOT)/Include/Common -I $(MAKE
 BUILD_CPPFLAGS = $(INCLUDE) -O2
 ifeq ($(DARWIN),Darwin)
 # assume clang or clang compatible flags on OS X
-BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-self-assign -Wno-unused-result -nostdlib -c -g
+BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-stringop-truncation -Wno-self-assign -Wno-unused-result -nostdlib -c -g
 else
-BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-unused-result -nostdlib -c -g
+BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-deprecated-declarations -Wno-stringop-truncation -Wno-unused-result -nostdlib -c -g
 endif
 BUILD_LFLAGS =
 BUILD_CXXFLAGS = -Wno-unused-result
-- 
2.14.1.3.gb7cf6e02401b




  reply	other threads:[~2018-03-02 18:03 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-02 18:09 [PATCH 0/3] BaseTools: let the C-language build utils compile with gcc-8 Laszlo Ersek
2018-03-02 18:09 ` Laszlo Ersek [this message]
2018-03-02 18:09 ` [PATCH 2/3] BaseTools/header.makefile: add "-Wno-restrict" Laszlo Ersek
2018-03-02 18:09 ` [PATCH 3/3] BaseTools/GenVtf: silence false "stringop-overflow" warning with memcpy() Laszlo Ersek
2018-03-05 14:13 ` [PATCH 0/3] BaseTools: let the C-language build utils compile with gcc-8 Gao, Liming
2018-03-05 21:41   ` Laszlo Ersek
2018-03-07  6:43   ` Gao, Liming
2018-03-07  9:11     ` Laszlo Ersek
2018-03-07  9:12       ` Ard Biesheuvel
2018-03-07 20:26         ` Laszlo Ersek

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