TianoCore BZ#700 <https://bugzilla.tianocore.org/show_bug.cgi?id=700>
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" [1] 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 unkown '-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 5 [2] (and also earlier, for that matter), so add the flag to the GCC5 toolchain, even if GCC 5 itself does not supports it. 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://gcc.gnu.org/onlinedocs/gcc-6.4.0/gcc/Warning-Options.html#index-Wunused-const-variable [2] https://gcc.gnu.org/onlinedocs/gcc-5.4.0/gcc/Warning-Options.html Cc: Yonghong Zhu <yonghong....@intel.com> Cc: Liming Gao <liming....@intel.com> Cc: Laszlo Ersek <ler...@redhat.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Thomas Lamprecht <t.lampre...@proxmox.com> --- I hope I CCed the correct people and got the style right :) BaseTools/Conf/tools_def.template | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/BaseTools/Conf/tools_def.template b/BaseTools/Conf/tools_def.template index ba1d1a16de..7db7a174c3 100755 --- a/BaseTools/Conf/tools_def.template +++ b/BaseTools/Conf/tools_def.template @@ -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 edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
