Jiewen: When CLANG9 is used, CLANG compiler always removes _fltused symbol, and cause the linker issue. __attribute__((used)) variable attribute informs the compiler that a static variable is to be retained in the object file, even if it is unreferenced.
So, I add this attribute for _fltused symbol and let compiler keep this symbol for linker. I find GCC and CLANG both supports this attribute. Then, I add it for GCC and CLANG both. Thanks Liming >-----Original Message----- >From: Yao, Jiewen >Sent: Friday, September 27, 2019 4:34 PM >To: devel@edk2.groups.io; Gao, Liming <liming....@intel.com> >Subject: RE: [edk2-devel] [Patch 09/12] CryptoPkg IntrinsicLib: Make _fltused >always be used > >Hi > >+int GLOBAL_USED _fltused = 1; > >May I know what is the use of GLOBAL_USED? Only for compiler stub symbol? > >If so, why we add __GNUC__ here? Any other usage? > >+#if defined(__GNUC__) || defined(__clang__) >+ #define GLOBAL_USED __attribute__((used)) >+#else >+ #define GLOBAL_USED >+#endif > >> -----Original Message----- >> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Liming >Gao >> Sent: Friday, September 27, 2019 3:47 PM >> To: devel@edk2.groups.io >> Subject: [edk2-devel] [Patch 09/12] CryptoPkg IntrinsicLib: Make _fltused >always >> be used >> >> With this change, global variable _fltused will not be removed by LTO >> >> Signed-off-by: Liming Gao <liming....@intel.com> >> --- >> CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c | 10 ++++++++-- >> 1 file changed, 8 insertions(+), 2 deletions(-) >> >> diff --git a/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c >> b/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c >> index 6e4d4a68cc..94fe341bec 100644 >> --- a/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c >> +++ b/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c >> @@ -2,7 +2,7 @@ >> Intrinsic Memory Routines Wrapper Implementation for OpenSSL-based >> Cryptographic Library. >> >> -Copyright (c) 2010 - 2018, Intel Corporation. All rights reserved.<BR> >> +Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR> >> SPDX-License-Identifier: BSD-2-Clause-Patent >> >> **/ >> @@ -13,9 +13,15 @@ SPDX-License-Identifier: BSD-2-Clause-Patent >> >> typedef UINTN size_t; >> >> +#if defined(__GNUC__) || defined(__clang__) >> + #define GLOBAL_USED __attribute__((used)) >> +#else >> + #define GLOBAL_USED >> +#endif >> + >> /* OpenSSL will use floating point support, and C compiler produces the >_fltused >> symbol by default. Simply define this symbol here to satisfy the linker. >> */ >> -int _fltused = 1; >> +int GLOBAL_USED _fltused = 1; >> >> /* Sets buffers to a specified character */ >> void * memset (void *dest, int ch, size_t count) >> -- >> 2.13.0.windows.1 >> >> >> -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#48263): https://edk2.groups.io/g/devel/message/48263 Mute This Topic: https://groups.io/mt/34309062/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
