Build failed when optimization -O2 is used

[kasjer]

Operating System

Windows 10

Board

pca10056, fomu,

Firmware

examples/device/cdc_msc or any other device build

What happened ?

Build fails when optimization is changed from -Os to -O2. In several places get_driver() (which can return NULL) is used without checking for NULL dereference.

It could be that it is false positive but maybe not. I'm using other compiler (xc32-gcc for microchip) that allows to have -Os only in PRO version (not free) so I'm stuck with -O2, which for arm/riscv/pic32 produces same warning about NULL dereference which is promoted to error.

How to reproduce ?

change -Os to -O2 in make.mk

Debug Log

arm

LINK _build/pca10056/cdc_msc.elf
............./tinyusb/src/device/usbd.c: In function 'configuration_reset':
............./tinyusb/src/device/usbd.c:454:18: error: potential null pointer dereference [-Werror=null-dereference]
  454 |     get_driver(i)->reset(rhport);
      |                  ^
compilation terminated due to -Wfatal-errors.
lto1.exe: all warnings being treated as errors

riscv

$ make BOARD=fomu V=1
CFLAGS  -flto -march=rv32i -mabi=ilp32 -nostdlib -DCFG_TUSB_MCU=OPT_MCU_VALENTYUSB_EPTRI -ggdb -fdata-sections -ffunction-sections -fsingle-precision-constant -fno-strict-aliasing -Wdouble-promotion -Wstrict-prototypes -Wstrict-overflow -Wall -Wextra -Werror -Wfatal-errors -Werror-implicit-function-declaration -Wfloat-equal -Wundef -Wshadow -Wwrite-strings -Wsign-compare -Wmissing-format-attribute -Wunreachable-code -Wcast-align -Wcast-function-type -Wcast-qual -Wnull-dereference -O2 -Itinyusb/hw/bsp/fomu/include -Itinyusb/hw/bsp/fomu -Isrc -Itinyusb/hw -Itinyusb/src

LDFLAGS -flto -march=rv32i -mabi=ilp32 -nostdlib -DCFG_TUSB_MCU=OPT_MCU_VALENTYUSB_EPTRI -ggdb -fdata-sections -ffunction-sections -fsingle-precision-constant -fno-strict-aliasing -Wdouble-promotion -Wstrict-prototypes -Wstrict-overflow -Wall -Wextra -Werror -Wfatal-errors -Werror-implicit-function-declaration -Wfloat-equal -Wundef -Wshadow -Wwrite-strings -Wsign-compare -Wmissing-format-attribute -Wunreachable-code -Wcast-align -Wcast-function-type -Wcast-qual -Wnull-dereference -O2 -Itinyusb/hw/bsp/fomu/include -Itinyusb/hw/bsp/fomu -Isrc -Itinyusb/hw -Itinyusb/src -Wl,-T,tinyusb/hw/bsp/fomu/fomu.ld -Wl,-Map=.map -Wl,-cref -Wl,-gc-sections -specs=nosys.specs -specs=nano.specs

ASFLAGS -flto -march=rv32i -mabi=ilp32 -nostdlib -DCFG_TUSB_MCU=OPT_MCU_VALENTYUSB_EPTRI -ggdb -fdata-sections -ffunction-sections -fsingle-precision-constant -fno-strict-aliasing -Wdouble-promotion -Wstrict-prototypes -Wstrict-overflow -Wall -Wextra -Werror -Wfatal-errors -Werror-implicit-function-declaration -Wfloat-equal -Wundef -Wshadow -Wwrite-strings -Wsign-compare -Wmissing-format-attribute -Wunreachable-code -Wcast-align -Wcast-function-type -Wcast-qual -Wnull-dereference -O2 -Itinyusb/hw/bsp/fomu/include -Itinyusb/hw/bsp/fomu -Isrc -Itinyusb/hw -Itinyusb/src


AS crt0-vexriscv_asm.o
CC dcd_eptri.o
CC fomu.o
CC board.o
CC main.o
CC msc_disk.o
CC usb_descriptors.o
CC tusb.o
CC tusb_fifo.o
CC usbd.o
.........../tinyusb/src/device/usbd.c: In function 'configuration_reset':
.........../tinyusb/src/device/usbd.c:454:18: error: potential null pointer dereference [-Werror=null-dereference]
     get_driver(i)->reset(rhport);
     ~~~~~~~~~~~~~^~~~~~~
compilation terminated due to -Wfatal-errors.
cc1.exe: all warnings being treated as errors
make: *** [../../rules.mk:130: _build/fomu/obj/src/device/usbd.o] Error 1

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