Reviewed-by: Liming Gao <[email protected]>
>-----Original Message----- >From: edk2-devel [mailto:[email protected]] On Behalf Of >Thomas Lamprecht >Sent: Friday, September 08, 2017 3:02 PM >To: [email protected] >Cc: Laszlo Ersek <[email protected]>; Gao, Liming <[email protected]>; >Ard Biesheuvel <[email protected]> >Subject: [edk2] [PATCH v2] BaseTools/GCC: set -Wno-unused-const-variables >on RELEASE builds > >TianoCore BZ#700 [1] > >Set the '-Wno-unused-const-variables' in RELEASE builds with the >GGC49 and GCC5 toolchain. > >This fixes the RELEASE build of OVMF with GCC in version 6 or newer. >GCC 6 added the '-Wunused-const-variable' warning, which gets >activated by '-Wunused-variable' and has the following behavior: >"Warn whenever a constant static variable is unused aside from its >declaration" [2] > >Commit 2ad6ba80a1bd58382bde6b994070f7c01d2fb48d introduced a case >where exactly this happens on a RELEASE build. All uses of the static >const variable are located in debug code only, which gets thrown out >by the compiler on RELEASE builds and thus triggers the >unused-const-variable warning. > >There is currently no GCC 6 toolchain target defined and doing so >would add a lot of boilerplate code. Instead, use the fact that GCC >ignores unknown '-Wno-*' options: > >"[...] if the -Wno- form is used [...] no diagnostic is produced for >-Wno-unknown-warning unless other diagnostics are being produced" > >This behavior is available in GCC 4.9 [3] (and also earlier, for that >matter), so add the flag to the GCC49 and GCC5 toolchain, even if >both GCC versions do not supports it. >GCC49 doesn't enables LTO whereas GCC5 does. As GCC 6.0 through 6.2 >had bugs relating to LTO there can be desire to use the GCC49 target >even if compiling with GCC 6, see 432f1d83f77a. > >Orient the changes on 20d00edf21d2 which moved the >'-Wno-unused-but-set-variable' flag to RELEASE builds only, as there >it ensure that it does not gets raised if the only usage of a >variable is in (then collapsed) debug code. > >[1] https://bugzilla.tianocore.org/show_bug.cgi?id=700 >[2] https://gcc.gnu.org/onlinedocs/gcc-6.4.0/gcc/Warning- >Options.html#index-Wunused-const-variable >[3] https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Warning-Options.html > >Cc: Yonghong Zhu <[email protected]> >Cc: Liming Gao <[email protected]> >Cc: Laszlo Ersek <[email protected]> >Cc: Ard Biesheuvel <[email protected]> >Contributed-under: TianoCore Contribution Agreement 1.1 >Signed-off-by: Thomas Lamprecht <[email protected]> >--- > >changes v1 -> v2: > * add the flag also to the GCC49 toolchain to allow using GCC 6 with > LTO disabled builds, thanks for the hints Laszlo and Liming! > * adapt commit message slightly, especially to the fact that GCC49 > gets the flag now too. > * CC Ard > > BaseTools/Conf/tools_def.template | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > >diff --git a/BaseTools/Conf/tools_def.template >b/BaseTools/Conf/tools_def.template >index ba1d1a16de..cbb5024c1b 100755 >--- a/BaseTools/Conf/tools_def.template >+++ b/BaseTools/Conf/tools_def.template >@@ -5179,7 +5179,7 @@ RELEASE_GCC48_AARCH64_CC_FLAGS = >DEF(GCC48_AARCH64_CC_FLAGS) -Wno-unused-but-s > *_GCC49_IA32_NASM_FLAGS = -f elf32 > > DEBUG_GCC49_IA32_CC_FLAGS = DEF(GCC49_IA32_CC_FLAGS) -Os >-RELEASE_GCC49_IA32_CC_FLAGS = DEF(GCC49_IA32_CC_FLAGS) -Os - >Wno-unused-but-set-variable >+RELEASE_GCC49_IA32_CC_FLAGS = DEF(GCC49_IA32_CC_FLAGS) -Os - >Wno-unused-but-set-variable -Wno-unused-const-variable > NOOPT_GCC49_IA32_CC_FLAGS = DEF(GCC49_IA32_CC_FLAGS) -O0 > > ################## >@@ -5207,7 +5207,7 @@ RELEASE_GCC49_IA32_CC_FLAGS = >DEF(GCC49_IA32_CC_FLAGS) -Os -Wno-unused-but > *_GCC49_X64_NASM_FLAGS = -f elf64 > > DEBUG_GCC49_X64_CC_FLAGS = DEF(GCC49_X64_CC_FLAGS) -Os >-RELEASE_GCC49_X64_CC_FLAGS = DEF(GCC49_X64_CC_FLAGS) -Os - >Wno-unused-but-set-variable >+RELEASE_GCC49_X64_CC_FLAGS = DEF(GCC49_X64_CC_FLAGS) -Os - >Wno-unused-but-set-variable -Wno-unused-const-variable > NOOPT_GCC49_X64_CC_FLAGS = DEF(GCC49_X64_CC_FLAGS) -O0 > > ################## >@@ -5240,7 +5240,7 @@ RELEASE_GCC49_X64_CC_FLAGS = >DEF(GCC49_X64_CC_FLAGS) -Os -Wno-unused-but-s > *_GCC49_ARM_CC_XIPFLAGS = DEF(GCC49_ARM_CC_XIPFLAGS) > > DEBUG_GCC49_ARM_CC_FLAGS = DEF(GCC49_ARM_CC_FLAGS) -O0 >-RELEASE_GCC49_ARM_CC_FLAGS = DEF(GCC49_ARM_CC_FLAGS) -Wno- >unused-but-set-variable >+RELEASE_GCC49_ARM_CC_FLAGS = DEF(GCC49_ARM_CC_FLAGS) -Wno- >unused-but-set-variable -Wno-unused-const-variable > NOOPT_GCC49_ARM_CC_FLAGS = DEF(GCC49_ARM_CC_FLAGS) -O0 > > ################## >@@ -5272,7 +5272,7 @@ RELEASE_GCC49_ARM_CC_FLAGS = >DEF(GCC49_ARM_CC_FLAGS) -Wno-unused-but-set-v > DEBUG_GCC49_AARCH64_DLINK_FLAGS = >DEF(GCC49_AARCH64_DLINK_FLAGS) -z common-page-size=0x1000 > DEBUG_GCC49_AARCH64_DLINK_XIPFLAGS = -z common-page-size=0x20 > >-RELEASE_GCC49_AARCH64_CC_FLAGS = DEF(GCC49_AARCH64_CC_FLAGS) >-Wno-unused-but-set-variable -mcmodel=tiny -fomit-frame-pointer >+RELEASE_GCC49_AARCH64_CC_FLAGS = DEF(GCC49_AARCH64_CC_FLAGS) >-Wno-unused-but-set-variable -Wno-unused-const-variable -mcmodel=tiny - >fomit-frame-pointer > RELEASE_GCC49_AARCH64_DLINK_FLAGS = >DEF(GCC49_AARCH64_DLINK_FLAGS) > > NOOPT_GCC49_AARCH64_CC_FLAGS = DEF(GCC49_AARCH64_CC_FLAGS) >-O0 -mcmodel=small >@@ -5326,7 +5326,7 @@ RELEASE_GCC49_AARCH64_DLINK_FLAGS = >DEF(GCC49_AARCH64_DLINK_FLAGS) > DEBUG_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) -flto -Os > DEBUG_GCC5_IA32_DLINK_FLAGS = DEF(GCC5_IA32_X64_DLINK_FLAGS) - >flto -Os -Wl,-m,elf_i386,--oformat=elf32-i386 > >-RELEASE_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) -flto -Os - >Wno-unused-but-set-variable >+RELEASE_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) -flto -Os - >Wno-unused-but-set-variable -Wno-unused-const-variable > RELEASE_GCC5_IA32_DLINK_FLAGS = DEF(GCC5_IA32_X64_DLINK_FLAGS) - >flto -Os -Wl,-m,elf_i386,--oformat=elf32-i386 > > NOOPT_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) -O0 >@@ -5358,7 +5358,7 @@ RELEASE_GCC5_IA32_DLINK_FLAGS = >DEF(GCC5_IA32_X64_DLINK_FLAGS) -flto -Os -Wl, > DEBUG_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) -flto - >DUSING_LTO -Os > DEBUG_GCC5_X64_DLINK_FLAGS = DEF(GCC5_X64_DLINK_FLAGS) -flto - >Os > >-RELEASE_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) -flto - >DUSING_LTO -Os -Wno-unused-but-set-variable >+RELEASE_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) -flto - >DUSING_LTO -Os -Wno-unused-but-set-variable -Wno-unused-const-variable > RELEASE_GCC5_X64_DLINK_FLAGS = DEF(GCC5_X64_DLINK_FLAGS) -flto - >Os > > NOOPT_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) -O0 >@@ -5393,7 +5393,7 @@ RELEASE_GCC5_X64_DLINK_FLAGS = >DEF(GCC5_X64_DLINK_FLAGS) -flto -Os > DEBUG_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) -O0 > DEBUG_GCC5_ARM_DLINK_FLAGS = DEF(GCC5_ARM_DLINK_FLAGS) > >-RELEASE_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) -flto - >Wno-unused-but-set-variable >+RELEASE_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) -flto - >Wno-unused-but-set-variable -Wno-unused-const-variable > RELEASE_GCC5_ARM_DLINK_FLAGS = DEF(GCC5_ARM_DLINK_FLAGS) -flto >-Os -L$(WORKSPACE)/ArmPkg/Library/GccLto -llto-arm -Wl,-plugin-opt=-pass- >through=-llto-arm > > NOOPT_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) -O0 >@@ -5428,7 +5428,7 @@ RELEASE_GCC5_ARM_DLINK_FLAGS = >DEF(GCC5_ARM_DLINK_FLAGS) -flto -Os -L$(WORKS > DEBUG_GCC5_AARCH64_DLINK_FLAGS = >DEF(GCC5_AARCH64_DLINK_FLAGS) -z common-page-size=0x1000 > DEBUG_GCC5_AARCH64_DLINK_XIPFLAGS = -z common-page-size=0x20 > >-RELEASE_GCC5_AARCH64_CC_FLAGS = DEF(GCC5_AARCH64_CC_FLAGS) - >flto -Wno-unused-but-set-variable -mcmodel=tiny -fomit-frame-pointer >+RELEASE_GCC5_AARCH64_CC_FLAGS = DEF(GCC5_AARCH64_CC_FLAGS) - >flto -Wno-unused-but-set-variable -Wno-unused-const-variable - >mcmodel=tiny -fomit-frame-pointer > RELEASE_GCC5_AARCH64_DLINK_FLAGS = >DEF(GCC5_AARCH64_DLINK_FLAGS) -flto -Os - >L$(WORKSPACE)/ArmPkg/Library/GccLto -llto-aarch64 -Wl,-plugin-opt=-pass- >through=-llto-aarch64 -Wno-lto-type-mismatch > > NOOPT_GCC5_AARCH64_CC_FLAGS = DEF(GCC5_AARCH64_CC_FLAGS) - >O0 -mcmodel=small >-- >2.11.0 > > >_______________________________________________ >edk2-devel mailing list >[email protected] >https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
