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-rw-r--r--platforms/avr/platform.mk18
1 files changed, 17 insertions, 1 deletions
diff --git a/platforms/avr/platform.mk b/platforms/avr/platform.mk
index 4d9cafaeef..0374e2e058 100644
--- a/platforms/avr/platform.mk
+++ b/platforms/avr/platform.mk
@@ -18,6 +18,13 @@ COMPILEFLAGS += -ffunction-sections
COMPILEFLAGS += -fdata-sections
COMPILEFLAGS += -fpack-struct
COMPILEFLAGS += -fshort-enums
+COMPILEFLAGS += -mcall-prologues
+
+# Linker relaxation is only possible if
+# link time optimizations are not enabled.
+ifeq ($(strip $(LTO_ENABLE)), no)
+ COMPILEFLAGS += -mrelax
+endif
ASFLAGS += $(AVR_ASFLAGS)
@@ -28,7 +35,16 @@ CFLAGS += -fno-strict-aliasing
CXXFLAGS += $(COMPILEFLAGS)
CXXFLAGS += -fno-exceptions -std=c++11
-LDFLAGS +=-Wl,--gc-sections
+LDFLAGS += -Wl,--gc-sections
+
+# Use AVR's libc minimal printf implementation which has less features
+# and thus can shave ~400 bytes. Usually we use the xprintf
+# implementation but keyboards that use s(n)printf automatically
+# pull in the AVR libc implementation, which is ~900 bytes heavy.
+AVR_USE_MINIMAL_PRINTF ?= no
+ifeq ($(strip $(AVR_USE_MINIMAL_PRINTF)), yes)
+ LDFLAGS += -Wl,--whole-archive -lprintf_min -Wl,--no-whole-archive
+endif
OPT_DEFS += -DF_CPU=$(F_CPU)UL