link time optimisations tried, but cant use debugger

Makefile

@@ -13,6 +13,7 @@ TARGET = ODriveFirmware
 # debug build?
 DEBUG = 1
 # optimization
+# OPT = -O3 -ffast-math -flto
 OPT = -O0 -ffast-math
 
 #######################################
@@ -116,7 +117,7 @@ LDSCRIPT = STM32F405RGTx_FLASH.ld
 # libraries
 LIBS = -lc -lm -lnosys
 LIBDIR =
-LDFLAGS = -mthumb -mcpu=cortex-m4 -mfpu=fpv4-sp-d16 -mfloat-abi=hard -specs=nano.specs -T$(LDSCRIPT) $(LIBDIR) $(LIBS) -Wl,-Map=$(BUILD_DIR)/$(TARGET).map,--cref -Wl,--gc-sections
+LDFLAGS = -mthumb -mcpu=cortex-m4 -mfpu=fpv4-sp-d16 -mfloat-abi=hard -specs=nano.specs $(OPT) -T$(LDSCRIPT) $(LIBDIR) $(LIBS) -Wl,-Map=$(BUILD_DIR)/$(TARGET).map,--cref -Wl,--gc-sections
 
 # default action: build all
 all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin

Middlewares/Third_Party/FreeRTOS/Source/include/task.h

@@ -1931,7 +1931,7 @@ BaseType_t xTaskRemoveFromUnorderedEventList( ListItem_t * pxEventListItem, cons
  * Sets the pointer to the current TCB to the TCB of the highest priority task
  * that is ready to run.
  */
-void vTaskSwitchContext( void ) PRIVILEGED_FUNCTION;
+void vTaskSwitchContext( void ) PRIVILEGED_FUNCTION __attribute__((used));
 
 /*
  * THESE FUNCTIONS MUST NOT BE USED FROM APPLICATION CODE.  THEY ARE USED BY

MotorControl/low_level.c

@@ -293,7 +293,7 @@ void pwm_trig_adc_cb(ADC_HandleTypeDef* hadc) {
 
 static bool check_timing() {
 #define log_size 32
-    static uint16_t timings[log_size];
+    static volatile uint16_t timings[log_size];
     static int idx = 0;
 
     uint16_t timing = htim1.Instance->CNT;