Add explicit "-mfpu=" for AArch32 commands

CMakeLists.txt

@@ -941,7 +941,6 @@ endfunction()
 set(multilib_yaml_content "")
 
 # Define which library variants to build and which flags to use.
-# The order is <arch> <name suffix> <compile flags> <multilib selection flags> <qemu params>
 add_library_variant(
     aarch64
     COMPILE_FLAGS "-march=armv8-a"
@@ -956,9 +955,12 @@ add_library_variant(
     RAM_SIZE 2M
     STACK_SIZE 8K
 )
+# For AArch32, clang uses different defaults for FPU selection than GCC, both
+# when "+fp" or "+fp.dp" are used and when no FPU specifier is provided in
+# "-march=". Using "-mfpu=" explicitly.
 add_library_variant(
     armv4t
-    COMPILE_FLAGS "-march=armv4t"
+    COMPILE_FLAGS "-march=armv4t -mfpu=none"
     MULTILIB_FLAGS "--target=armv4t-none-unknown-eabi -mfpu=none"
     QEMU_MACHINE "none"
     QEMU_CPU "ti925t"
@@ -973,7 +975,7 @@ add_library_variant(
 )
 add_library_variant(
     armv5te
-    COMPILE_FLAGS "-march=armv5te"
+    COMPILE_FLAGS "-march=armv5te -mfpu=none"
     MULTILIB_FLAGS "--target=armv5e-none-unknown-eabi -mfpu=none"
     QEMU_MACHINE "none"
     QEMU_CPU "arm926"
@@ -989,7 +991,7 @@ add_library_variant(
 add_library_variant(
     armv6m
     SUFFIX soft_nofp
-    COMPILE_FLAGS "-mfloat-abi=soft -march=armv6m"
+    COMPILE_FLAGS "-mfloat-abi=soft -march=armv6m -mfpu=none"
     MULTILIB_FLAGS "--target=thumbv6m-none-unknown-eabi -mfpu=none"
     QEMU_MACHINE "mps2-an385"
     BOOT_FLASH_ADDRESS 0x00000000
@@ -1000,8 +1002,6 @@ add_library_variant(
     RAM_SIZE 2M
     STACK_SIZE 4K
 )
-# clang does not correctly handle +nofp and +fp for armv7a and armv7r in march.
-# Using mfpu as a workaround.
 add_library_variant(
     armv7a
     SUFFIX soft_nofp
@@ -1069,7 +1069,7 @@ add_library_variant(
 add_library_variant(
     armv7m
     SUFFIX soft_nofp
-    COMPILE_FLAGS "-mfloat-abi=soft -march=armv7m+nofp"
+    COMPILE_FLAGS "-mfloat-abi=soft -march=armv7m -mfpu=none"
     MULTILIB_FLAGS "--target=thumbv7m-none-unknown-eabi -mfpu=none"
     QEMU_MACHINE "mps2-an385"
     QEMU_CPU "cortex-m3"
@@ -1144,7 +1144,7 @@ add_library_variant(
 add_library_variant(
     armv8m.main
     SUFFIX soft_nofp
-    COMPILE_FLAGS "-mfloat-abi=soft -march=armv8m.main+nofp"
+    COMPILE_FLAGS "-mfloat-abi=soft -march=armv8m.main -mfpu=none"
     MULTILIB_FLAGS "--target=thumbv8m.main-none-unknown-eabi -mfpu=none"
     QEMU_MACHINE "mps2-an505"
     QEMU_CPU "cortex-m33"
@@ -1159,8 +1159,8 @@ add_library_variant(
 add_library_variant(
     armv8m.main
     SUFFIX hard_fp
-    COMPILE_FLAGS "-mfloat-abi=hard -march=armv8m.main+fp"
-    MULTILIB_FLAGS "--target=thumbv8m.main-none-unknown-eabihf -mfpu=fpv5-d16"
+    COMPILE_FLAGS "-mfloat-abi=hard -march=armv8m.main -mfpu=fpv5-sp-d16"
+    MULTILIB_FLAGS "--target=thumbv8m.main-none-unknown-eabihf -mfpu=fpv5-sp-d16"
     QEMU_MACHINE "mps2-an505"
     QEMU_CPU "cortex-m33"
     BOOT_FLASH_ADDRESS 0x10000000
@@ -1174,7 +1174,7 @@ add_library_variant(
 add_library_variant(
     armv8.1m.main
     SUFFIX soft_nofp_nomve
-    COMPILE_FLAGS "-mfloat-abi=soft -march=armv8.1m.main+nofp+nomve"
+    COMPILE_FLAGS "-mfloat-abi=soft -march=armv8.1m.main+nomve -mfpu=none"
     MULTILIB_FLAGS "--target=thumbv8.1m.main-none-unknown-eabi -mfpu=none"
     QEMU_MACHINE "mps3-an547"
     QEMU_CPU "cortex-m55"
@@ -1188,8 +1188,8 @@ add_library_variant(
 )
 add_library_variant(
     armv8.1m.main
-    SUFFIX hard_fp
-    COMPILE_FLAGS "-mfloat-abi=hard -march=armv8.1m.main+fp"
+    SUFFIX hard_fp_nomve
+    COMPILE_FLAGS "-mfloat-abi=hard -march=armv8.1m.main+nomve -mfpu=fp-armv8-fullfp16-sp-d16"
     MULTILIB_FLAGS "--target=thumbv8.1m.main-none-unknown-eabihf -march=thumbv8.1m.main+fp16 -mfpu=fp-armv8-fullfp16-sp-d16"
     QEMU_MACHINE "mps3-an547"
     QEMU_CPU "cortex-m55"
@@ -1201,10 +1201,25 @@ add_library_variant(
     RAM_SIZE 2M
     STACK_SIZE 4K
 )
+add_library_variant(
+    armv8.1m.main
+    SUFFIX hard_fpdp_nomve
+    COMPILE_FLAGS "-mfloat-abi=hard -march=armv8.1m.main+nomve -mfpu=fp-armv8-fullfp16-d16"
+    MULTILIB_FLAGS "--target=thumbv8.1m.main-none-unknown-eabihf -march=thumbv8.1m.main+fp16 -mfpu=fp-armv8-fullfp16-d16"
+    QEMU_MACHINE "mps3-an547"
+    QEMU_CPU "cortex-m55"
+    BOOT_FLASH_ADDRESS 0x00000000
+    BOOT_FLASH_SIZE 512K
+    FLASH_ADDRESS 0x01000000
+    FLASH_SIZE 2M
+    RAM_ADDRESS 0x60000000
+    RAM_SIZE 2M
+    STACK_SIZE 4K
+)
 add_library_variant(
     armv8.1m.main
     SUFFIX hard_nofp_mve
-    COMPILE_FLAGS "-mfloat-abi=hard -march=armv8.1m.main+nofp+mve"
+    COMPILE_FLAGS "-mfloat-abi=hard -march=armv8.1m.main+mve -mfpu=none"
     MULTILIB_FLAGS "--target=thumbv8.1m.main-none-unknown-eabihf -march=thumbv8.1m.main+dsp+mve -mfpu=none"
     QEMU_MACHINE "mps3-an547"
     QEMU_CPU "cortex-m55"

README.md

@@ -93,6 +93,7 @@ find . -type f -perm +0111 | xargs xattr -d com.apple.quarantine
 
 To use the toolchain, on the command line you need to provide the following options:
 * The target triple.
+* The FPU to use.
 * Disabling C++ exceptions and RTTI that are not supported by the standard library provided yet.
 * The C runtime library: either `crt0` or `crt0-semihost`.
 * The semihosting library, if using `crt0-semihost`.
@@ -107,6 +108,7 @@ For example:
 $ PATH=<install-dir>/LLVMEmbeddedToolchainForArm-<revision>/bin:$PATH
 $ clang \
 --target=armv6m-none-eabi \
+-mfpu=none \
 -fno-exceptions \
 -fno-rtti \
 -lcrt0-semihost \
@@ -134,6 +136,7 @@ directories of the libraries you want to use. For example:
 $ clang \
 --sysroot=<install-dir>/LLVMEmbeddedToolchainForArm-<revision>/lib/clang-runtimes/arm-none-eabi/armv6m_soft_nofp \
 --target=armv6m-none-eabi \
+-mfpu=none \
 -fno-exceptions \
 -fno-rtti \
 -lcrt0-semihost \
@@ -142,6 +145,9 @@ $ clang \
 -o example example.c
 ```
 
+The FPU selection can be skipped, but it is not recommended to as the defaults
+are different to GCC ones.
+
 Binary releases of the LLVM Embedded Toolchain for Arm are based on release
 branches of the upstream LLVM Project, thus can safely be used with all tools
 provided by LLVM [releases|https://github.com/llvm/llvm-project/releases]

packagetest/hello.c

@@ -1,4 +1,4 @@
-// RUN: %clang --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -T %S/Inputs/microbit.ld %s -o %t.out
+// RUN: %clang --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -T %S/Inputs/microbit.ld %s -o %t.out
 // RUN: qemu-system-arm -M microbit -semihosting -nographic -device loader,file=%t.out 2>&1 | FileCheck %s
 
 #include <stdio.h>

packagetest/hello.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -T %S/Inputs/microbit.ld %s -o %t.out
+// RUN: %clangxx --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -T %S/Inputs/microbit.ld %s -o %t.out
 // RUN: qemu-system-arm -M microbit -semihosting -nographic -device loader,file=%t.out 2>&1 | FileCheck %s
 
 // Include as many C++17 headers as possible.

samples/Makefile.conf

@@ -19,7 +19,7 @@ ifndef BIN_PATH
 BIN_PATH=../../../bin
 endif
 
-MICROBIT_TARGET=--target=armv6m-none-eabi -march=armv6m -mfloat-abi=soft 
+MICROBIT_TARGET=--target=armv6m-none-eabi -march=armv6m -mfpu=none -mfloat-abi=soft
 AARCH64_TARGET=--target=aarch64-none-elf
 
 CRT=-lcrt0

samples/src/baremetal-semihosting/make.bat

@@ -49,6 +49,6 @@ if exist hello.hex del /q hello.hex
 @exit /B 1
 
 :build_fn
-%BIN_PATH%\clang.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -g -T ..\..\ldscripts\microbit.ld -o hello.elf hello.c
+%BIN_PATH%\clang.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -g -T ..\..\ldscripts\microbit.ld -o hello.elf hello.c
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B

samples/src/baremetal-uart/make.bat

@@ -49,6 +49,6 @@ if exist hello.hex del /q hello.hex
 @exit /B 1
 
 :build_fn
-%BIN_PATH%\clang.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0 -g -T ..\..\ldscripts\microbit.ld -o hello.elf hello.c
+%BIN_PATH%\clang.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0 -g -T ..\..\ldscripts\microbit.ld -o hello.elf hello.c
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B

samples/src/cpp-baremetal-semihosting-cfi/make.bat

@@ -56,13 +56,13 @@ if exist hello.hex del /q hello.hex
 @exit /B 1
 
 :build_fn
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -fno-exceptions -fno-rtti -flto -fsanitize=cfi -fvisibility=hidden -fno-sanitize-ignorelist -g -c hello.cpp
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -flto -T ..\..\ldscripts\microbit.ld -g -o hello.elf hello.o
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -fno-exceptions -fno-rtti -flto -fsanitize=cfi -fvisibility=hidden -fno-sanitize-ignorelist -g -c hello.cpp
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -flto -T ..\..\ldscripts\microbit.ld -g -o hello.elf hello.o
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B
 
 :build_no_cfi_fn
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -fno-exceptions -fno-rtti -flto -g -c hello.cpp
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -flto -T ..\..\ldscripts\microbit.ld -g -o hello.elf hello.o
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -fno-exceptions -fno-rtti -flto -g -c hello.cpp
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -flto -T ..\..\ldscripts\microbit.ld -g -o hello.elf hello.o
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B

samples/src/cpp-baremetal-semihosting-prof/make.bat

@@ -58,7 +58,7 @@ if exist proflib.o del /q proflib.o
 @exit /B 1
 
 :build_fn
-%BIN_PATH%\clang.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -g -c proflib.c
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -g -T ..\..\ldscripts\microbit.ld -fprofile-instr-generate -fcoverage-mapping -o hello.elf hello.cpp proflib.o
+%BIN_PATH%\clang.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -g -c proflib.c
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -g -T ..\..\ldscripts\microbit.ld -fprofile-instr-generate -fcoverage-mapping -o hello.elf hello.cpp proflib.o
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B

samples/src/cpp-baremetal-semihosting-ubsan/make.bat

@@ -55,11 +55,11 @@ if exist hello.hex del /q hello.hex
 @exit /B 1
 
 :build_fn
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti --std=c++17 -fsanitize=undefined -fsanitize-minimal-runtime -g -T ../../ldscripts/microbit.ld -o hello.elf *.cpp
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti --std=c++17 -fsanitize=undefined -fsanitize-minimal-runtime -g -T ../../ldscripts/microbit.ld -o hello.elf *.cpp
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B
 
 :build_trap_fn
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti --std=c++17 -fsanitize=undefined -fsanitize-trap=all -g -T ../../ldscripts/microbit.ld -o hello.elf *.cpp
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti --std=c++17 -fsanitize=undefined -fsanitize-trap=all -g -T ../../ldscripts/microbit.ld -o hello.elf *.cpp
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B

samples/src/cpp-baremetal-semihosting/make.bat

@@ -49,6 +49,6 @@ if exist hello.hex del /q hello.hex
 @exit /B 1
 
 :build_fn
-%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -g -T ..\..\ldscripts\microbit.ld -o hello.elf hello.cpp
+%BIN_PATH%\clang++.exe --target=armv6m-none-eabi -mfloat-abi=soft -march=armv6m -mfpu=none -lcrt0-semihost -lsemihost -fno-exceptions -fno-rtti -g -T ..\..\ldscripts\microbit.ld -o hello.elf hello.cpp
 %BIN_PATH%\llvm-objcopy.exe -O ihex hello.elf hello.hex
 @exit /B

test-support/picolibc-test-wrapper.py

@@ -18,9 +18,9 @@
     # https://github.com/picolibc/picolibc/pull/500
     "picolibc_aarch64-build/test/math_errhandling",
     "picolibc_aarch64-build/test/test-fma",
-    "picolibc_armv7em_hard_fpv4_sp_d16-build/test/math_errhandling",
     "picolibc_armv7m_soft_fpv4_sp_d16-build/test/math_errhandling",
-    "picolibc_armv8.1m.main_hard_fp-build/test/math_errhandling",
+    "picolibc_armv7em_hard_fpv4_sp_d16-build/test/math_errhandling",
+    "picolibc_armv8.1m.main_hard_fp_nomve-build/test/math_errhandling",
     "picolibc_armv8.1m.main_hard_nofp_mve-build/test/fenv",
     "picolibc_armv8.1m.main_hard_nofp_mve-build/test/math_errhandling",
 

test/multilib/armv4t.test

@@ -1,2 +1,2 @@
-# RUN: %clang -print-multi-directory --target=arm-none-eabi | FileCheck %s
+# RUN: %clang -print-multi-directory --target=arm-none-eabi -mfpu=none | FileCheck %s
 # CHECK: arm-none-eabi/armv4t

test/multilib/armv5e.test

@@ -1,2 +1,2 @@
-# RUN: %clang -print-multi-directory --target=armv5e-none-eabi | FileCheck %s
+# RUN: %clang -print-multi-directory --target=armv5e-none-eabi -mfpu=none | FileCheck %s
 # CHECK: arm-none-eabi/armv5te

test/multilib/armv6m.test

@@ -1,2 +1,2 @@
-# RUN: %clang -print-multi-directory --target=armv6m-none-eabi | FileCheck %s
+# RUN: %clang -print-multi-directory --target=armv6m-none-eabi -mfpu=none | FileCheck %s
 # CHECK: arm-none-eabi/armv6m_soft_nofp

test/multilib/armv7m.test

@@ -1,5 +1,5 @@
-# RUN: %clang -print-multi-directory --target=armv7m-none-eabi | FileCheck %s
+# RUN: %clang -print-multi-directory --target=armv7m-none-eabi -mfpu=none | FileCheck %s
 # CHECK: arm-none-eabi/armv7m_soft_nofp
 
-# RUN: %clang -print-multi-directory --target=armv7m-none-eabi -mfloat-abi=softfp | FileCheck --check-prefix=SOFT_FPV4 %s
+# RUN: %clang -print-multi-directory --target=armv7m-none-eabi -mfpu=none -mfloat-abi=softfp | FileCheck --check-prefix=SOFT_FPV4 %s
 # SOFT_FPV4: arm-none-eabi/armv7m_soft_fpv4_sp_d16

test/multilib/armv8.1m.main.test

@@ -1,10 +1,13 @@
 # RUN: %clang -print-multi-directory --target=armv8.1m.main-none-eabi -mfpu=none | FileCheck %s
 # CHECK: arm-none-eabi/armv8.1m.main_soft_nofp
 
-# RUN: %clang -print-multi-directory --target=armv8.1m.main-none-eabihf -march=armv8.1m.main+fp | FileCheck --check-prefix=HARD %s
-# HARD: arm-none-eabi/armv8.1m.main_hard_fp
+# RUN: %clang -print-multi-directory --target=armv8.1m.main-none-eabihf -march=armv8.1m.main -mfpu=fp-armv8-fullfp16-sp-d16 | FileCheck --check-prefix=HARD_FP %s
+# HARD_FP: arm-none-eabi/armv8.1m.main_hard_fp_nomve
 
-# RUN: %clang -print-multi-directory --target=armv8.1m.main-none-eabihf -march=armv8.1m.main+nofp+mve | FileCheck --check-prefix=MVE %s
+# RUN: %clang -print-multi-directory --target=armv8.1m.main-none-eabihf -march=armv8.1m.main -mfpu=fp-armv8-fullfp16-d16 | FileCheck --check-prefix=HARD_FPDP %s
+# HARD_FPDP: arm-none-eabi/armv8.1m.main_hard_fpdp_nomve
+
+# RUN: %clang -print-multi-directory --target=armv8.1m.main-none-eabihf -march=armv8.1m.main+mve -mfpu=none | FileCheck --check-prefix=MVE %s
 # MVE: arm-none-eabi/armv8.1m.main_hard_nofp_mve
 
 # RUN: %clang -print-multi-flags-experimental --target=arm-none-eabihf -mcpu=cortex-m55 | FileCheck --check-prefix=CORTEXM55 %s

test/multilib/armv8m.main.test

@@ -1,5 +1,5 @@
 # RUN: %clang -print-multi-directory --target=armv8m.main-none-eabi -mfpu=none | FileCheck %s
 # CHECK: arm-none-eabi/armv8m.main_soft_nofp
 
-# RUN: %clang -print-multi-directory --target=armv8m.main-none-eabihf | FileCheck --check-prefix=HARD %s
+# RUN: %clang -print-multi-directory --target=armv8m.main-none-eabihf -mfpu=fpv5-sp-d16 | FileCheck --check-prefix=HARD %s
 # HARD: arm-none-eabi/armv8m.main_hard_fp