From adc3f61912ec10e714a02a06fd2e04a9b4907cf9 Mon Sep 17 00:00:00 2001 From: Udit Jain Date: Fri, 24 Jul 2026 05:31:18 +0530 Subject: [PATCH] libs/libbuiltin/compiler-rt: skip unsupported Arm VFP builtins asm The compiler-rt builtins build globs every arm/*.S source, but several of those hand-written assembly files require FPU features the target may not have. Upstream compiler-rt selects them conditionally; NuttX did not, so BUILTIN_COMPILER_RT builds for single-precision-FPU Arm targets (e.g. Cortex-M33, -mfpu=fpv5-sp-d16) failed to assemble with errors such as "selected FPU does not support instruction -- vadd.f64". Filter the source list to match the configured FPU, in both the Makefile and CMake builds: - chkstk.S / chkstk2.S are Windows/MinGW-only stack probes, always dropped; - with no hardware FPU (!CONFIG_ARCH_FPU) all arm/*vfp.S are dropped; - with a single-precision FPU (!CONFIG_ARCH_DPFPU) the double-precision *df*vfp.S routines are dropped. Reproduced against compiler-rt 17.0.1 with arm-none-eabi-gcc 14.2 using the Cortex-M33 single-precision flags: 18 of 86 arm/*.S files failed to assemble (17 double-precision *df*vfp.S plus chkstk.S); after the filter all remaining 68 files assemble cleanly. Fixes: https://github.com/apache/nuttx/issues/17386 Generated-by: Claude (Anthropic) Signed-off-by: Udit Jain --- libs/libbuiltin/compiler-rt/CMakeLists.txt | 39 ++++++++++++++++++++++ libs/libbuiltin/compiler-rt/Make.defs | 27 +++++++++++++++ 2 files changed, 66 insertions(+) diff --git a/libs/libbuiltin/compiler-rt/CMakeLists.txt b/libs/libbuiltin/compiler-rt/CMakeLists.txt index d1fa3f444fcf5..81d3e6d4e0149 100644 --- a/libs/libbuiltin/compiler-rt/CMakeLists.txt +++ b/libs/libbuiltin/compiler-rt/CMakeLists.txt @@ -114,6 +114,45 @@ if(CONFIG_BUILTIN_COMPILER_RT) list(REMOVE_ITEM RT_BUILTINS_SRCS ${x86_80_BIT_SOURCES}) endif() + # The Arm builtins ship hand-written VFP assembly whose FPU requirements the + # globs above ignore, so assemble only the files the configured FPU supports + # (upstream compiler-rt selects them conditionally). chkstk.S and chkstk2.S + # are Windows/MinGW-only stack probes; every *vfp.S needs a hardware FPU; and + # the double-precision *df*vfp.S routines additionally need a double-precision + # FPU. Without this, single-precision-FPU targets such as Cortex-M33 + # (fpv5-sp-d16) fail with "selected FPU does not support instruction". See + # apache/nuttx#17386. + if(CONFIG_ARCH_ARM) + set(RT_BUILTINS_ARM_EXCLUDE ${BUILTINS_DIR}/arm/chkstk.S + ${BUILTINS_DIR}/arm/chkstk2.S) + if(NOT CONFIG_ARCH_FPU) + file(GLOB RT_BUILTINS_ARM_VFP ${BUILTINS_DIR}/arm/*vfp.S) + list(APPEND RT_BUILTINS_ARM_EXCLUDE ${RT_BUILTINS_ARM_VFP}) + elseif(NOT CONFIG_ARCH_DPFPU) + list( + APPEND + RT_BUILTINS_ARM_EXCLUDE + ${BUILTINS_DIR}/arm/adddf3vfp.S + ${BUILTINS_DIR}/arm/divdf3vfp.S + ${BUILTINS_DIR}/arm/eqdf2vfp.S + ${BUILTINS_DIR}/arm/extendsfdf2vfp.S + ${BUILTINS_DIR}/arm/fixdfsivfp.S + ${BUILTINS_DIR}/arm/fixunsdfsivfp.S + ${BUILTINS_DIR}/arm/floatsidfvfp.S + ${BUILTINS_DIR}/arm/floatunssidfvfp.S + ${BUILTINS_DIR}/arm/gedf2vfp.S + ${BUILTINS_DIR}/arm/gtdf2vfp.S + ${BUILTINS_DIR}/arm/ledf2vfp.S + ${BUILTINS_DIR}/arm/ltdf2vfp.S + ${BUILTINS_DIR}/arm/muldf3vfp.S + ${BUILTINS_DIR}/arm/nedf2vfp.S + ${BUILTINS_DIR}/arm/subdf3vfp.S + ${BUILTINS_DIR}/arm/truncdfsf2vfp.S + ${BUILTINS_DIR}/arm/unorddf2vfp.S) + endif() + list(REMOVE_ITEM RT_BUILTINS_SRCS ${RT_BUILTINS_ARM_EXCLUDE}) + endif() + if(NOT CONFIG_COVERAGE_NONE) target_compile_options(rt.builtins PRIVATE -fno-profile-instr-generate -fno-coverage-mapping) diff --git a/libs/libbuiltin/compiler-rt/Make.defs b/libs/libbuiltin/compiler-rt/Make.defs index d5b66a294b2b9..fbee147b0a0e9 100644 --- a/libs/libbuiltin/compiler-rt/Make.defs +++ b/libs/libbuiltin/compiler-rt/Make.defs @@ -108,6 +108,33 @@ ifeq ($(CONFIG_ARCH_X86_64),) CSRCS := $(filter-out $(x86_80_BIT_SOURCES), $(CSRCS)) endif +# The Arm builtins ship hand-written VFP assembly whose FPU requirements the +# wildcard glob above ignores. Upstream compiler-rt selects these files +# conditionally, so assemble only the ones the configured FPU supports; +# otherwise single-precision-FPU targets (e.g. Cortex-M33, fpv5-sp-d16) fail +# with "selected FPU does not support instruction". See apache/nuttx#17386. +# - chkstk.S / chkstk2.S are Windows/MinGW-only stack probes; +# - every *vfp.S needs a hardware FPU; +# - the double-precision *df*vfp.S routines additionally need a +# double-precision FPU. + +ifeq ($(CONFIG_ARCH_ARM),y) + COMPILER_RT_ARM_EXCLUDE := chkstk.S chkstk2.S +ifneq ($(CONFIG_ARCH_FPU),y) + COMPILER_RT_ARM_EXCLUDE += $(notdir \ + $(wildcard compiler-rt/compiler-rt/lib/builtins/arm/*vfp.S)) +else ifneq ($(CONFIG_ARCH_DPFPU),y) + COMPILER_RT_ARM_EXCLUDE += adddf3vfp.S divdf3vfp.S eqdf2vfp.S extendsfdf2vfp.S + COMPILER_RT_ARM_EXCLUDE += fixdfsivfp.S fixunsdfsivfp.S floatsidfvfp.S + COMPILER_RT_ARM_EXCLUDE += floatunssidfvfp.S gedf2vfp.S gtdf2vfp.S ledf2vfp.S + COMPILER_RT_ARM_EXCLUDE += ltdf2vfp.S muldf3vfp.S nedf2vfp.S subdf3vfp.S + COMPILER_RT_ARM_EXCLUDE += truncdfsf2vfp.S unorddf2vfp.S +endif + ASRCS := $(filter-out $(addprefix \ + compiler-rt/compiler-rt/lib/builtins/arm/, $(COMPILER_RT_ARM_EXCLUDE)), \ + $(ASRCS)) +endif + endif ################# Profile Library #################