+GOCFLAGS = $(CFLAGS)
+
+# Pass additional PGO and LTO compiler options to the PGO build.
+BUILD_CFLAGS = $(PGO_BUILD_CFLAGS) $(PGO_BUILD_LTO_CFLAGS)
+override CFLAGS += $(BUILD_CFLAGS)
+override CXXFLAGS += $(BUILD_CFLAGS)
+
+# Additional PGO and LTO compiler options to generate profiling data
+# for the PGO build.
+PGO_BUILD_GEN_FLAGS_TO_PASS = \
+ PGO_BUILD_CFLAGS="@PGO_BUILD_GEN_CFLAGS@" \
+ PGO_BUILD_LTO_CFLAGS="@PGO_BUILD_LTO_CFLAGS@"
+
+# NB: Filter out any compiler options which may fail PGO training runs.
+PGO_BUILD_TRAINING_CFLAGS:= \
+ $(filter-out -Werror=%,$(CFLAGS))
+PGO_BUILD_TRAINING_CXXFLAGS:=\
+ $(filter-out -Werror=%,$(CXXFLAGS))
+PGO_BUILD_TRAINING_CFLAGS:= \
+ $(filter-out -Wall,$(PGO_BUILD_TRAINING_CFLAGS))
+PGO_BUILD_TRAINING_CXXFLAGS:= \
+ $(filter-out -Wall,$(PGO_BUILD_TRAINING_CXXFLAGS))
+PGO_BUILD_TRAINING_CFLAGS:= \
+ $(filter-out -specs=%,$(PGO_BUILD_TRAINING_CFLAGS))
+PGO_BUILD_TRAINING_CXXFLAGS:= \
+ $(filter-out -specs=%,$(PGO_BUILD_TRAINING_CXXFLAGS))
+PGO_BUILD_TRAINING_FLAGS_TO_PASS = \
+ PGO_BUILD_TRAINING=yes \
+ CFLAGS_FOR_TARGET="$(PGO_BUILD_TRAINING_CFLAGS)" \
+ CXXFLAGS_FOR_TARGET="$(PGO_BUILD_TRAINING_CXXFLAGS)"
+
+# Ignore "make check" errors in PGO training runs.
+PGO_BUILD_TRAINING_MFLAGS = -i
+
+# Additional PGO and LTO compiler options to use profiling data for the
+# PGO build.
+PGO_BUILD_USE_FLAGS_TO_PASS = \
+ PGO_BUILD_CFLAGS="@PGO_BUILD_USE_CFLAGS@" \
+ PGO_BUILD_LTO_CFLAGS="@PGO_BUILD_LTO_CFLAGS@"
+
+# PGO training targets for the PGO build. FIXME: Add gold tests to
+# training.
+PGO-TRAINING-TARGETS = binutils gas gdb ld sim
+PGO_BUILD_TRAINING = $(addprefix maybe-check-,$(PGO-TRAINING-TARGETS))
+
+CREATE_GCOV = create_gcov
+
+TFLAGS =
+
+# Defaults for all stages; some are overridden below.
+
+STAGE_CFLAGS = $(BOOT_CFLAGS)
+STAGE_TFLAGS = $(TFLAGS)
+STAGE_CONFIGURE_FLAGS=@stage2_werror_flag@