On 09/08/17 09:01, Thomas Lamprecht wrote: > 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 >
I added the R-b tags from Liming, Ard, and myself. I also fixed up the subject line: -BaseTools/GCC: set -Wno-unused-const-variables on RELEASE builds +BaseTools/GCC: set -Wno-unused-const-variable on RELEASE builds Pushed as commit 8b6366f87584. Thanks! Laszlo _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
