From a16a330da54afd392252d7ea04139fd4702f48f8 Mon Sep 17 00:00:00 2001
From: Angus Gratton <angus@redyak.com.au>
Date: Mon, 15 Aug 2022 16:07:00 +1000
Subject: [PATCH] nrf,stm32: Don't enable debug info by default if LTO is on.

It seems sometimes gcc with LTO will generate otherwise valid assembly
listings that cause 'as' to error out when generating DWARF debug info; see
https://sourceware.org/bugzilla/show_bug.cgi?id=29494

Therefore, don't enable -g by default if LTO is on.

Enabling LTO=1 DEBUG=1 is still possible but may result in random errors
at link time due to 'as' (the error in this case is "Error: unaligned
opcodes detected in executable segment", and the only other easy workaround
is CFLAGS+=-fno-jump-tables which may increase code size significantly).

Follows on from fdfe4eca745dce5f20fb65a3c197006b9053999a
---
 ports/nrf/Makefile   | 6 ++++--
 ports/stm32/Makefile | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 23be4430f3..bc295cac80 100644
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -138,12 +138,14 @@ LDFLAGS += -Wl,'--defsym=_fs_size=$(FS_SIZE)'
 endif
 
 #Debugging/Optimization
-CFLAGS += -g  # always include debug info in the ELF
 ifeq ($(DEBUG), 1)
 #ASMFLAGS += -g -gtabs+
-CFLAGS += -O0
+CFLAGS += -g -O0
 LDFLAGS += -O0
 else
+ifneq ($(LTO), 1)
+CFLAGS += -g  # always include debug info in the ELF, unless LTO is on
+endif
 CFLAGS += -Os -DNDEBUG
 LDFLAGS += -Os
 endif
diff --git a/ports/stm32/Makefile b/ports/stm32/Makefile
index 657524798c..14a93a5aa7 100644
--- a/ports/stm32/Makefile
+++ b/ports/stm32/Makefile
@@ -114,13 +114,15 @@ $(BUILD)/stm32_it.o $(BUILD)/pendsv.o: CFLAGS += -fno-lto
 endif
 
 # Debugging/Optimization
-CFLAGS += -g  # always include debug info in the ELF
 ifeq ($(DEBUG), 1)
-CFLAGS += -DPENDSV_DEBUG
+CFLAGS += -g -DPENDSV_DEBUG
 COPT ?= -Og
 # Disable text compression in debug builds
 MICROPY_ROM_TEXT_COMPRESSION = 0
 else
+ifneq ($(LTO), 1)
+CFLAGS += -g  # always include debug info in the ELF, unless LTO is on
+endif
 COPT ?= -Os -DNDEBUG
 endif