Add armclang support for target based on Arm Corstone-300 software

Armclang need to use -ffp-mode=full because quantization unit test is
using NaN and without this use of NaN is undefined behavior.
Because of a compiler defect which only occurs with -ffp-mode=full a
workaround is done in the lstm unit test. The workaround prevents
implicit conversion from double to float. Since many of those
conversions would be inexact, the compiler would not consider those
conversions as constant expressions with -ffp-mode=full.

BUG=https://github.com/tensorflow/tflite-micro/issues/1305

tensorflow/lite/experimental/microfrontend/lib/kiss_fft_int16.cc

+#include <cstdint>
+
 #include "tensorflow/lite/experimental/microfrontend/lib/kiss_fft_common.h"
 
 #define FIXED_POINT 16

tensorflow/lite/micro/examples/micro_speech/audio_provider_test.cc

-/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+/* Copyright 2022 The TensorFlow Authors. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -41,6 +41,7 @@ TF_LITE_MICRO_TEST(TestAudioProvider) {
   for (int i = 0; i < audio_samples_size; ++i) {
     total += audio_samples[i];
   }
+  (void)total;
 }
 
 TF_LITE_MICRO_TEST(TestTimer) {

tensorflow/lite/micro/examples/person_detection/image_provider_test.cc

-/* Copyright 2019 The TensorFlow Authors. All Rights Reserved.
+/* Copyright 2022 The TensorFlow Authors. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -37,6 +37,7 @@ TF_LITE_MICRO_TEST(TestImageProvider) {
   for (int i = 0; i < kMaxImageSize; ++i) {
     total += image_data[i];
   }
+  (void)total;
 }
 
 TF_LITE_MICRO_TESTS_END

tensorflow/lite/micro/tools/ci_build/test_cortex_m_corstone_300.sh

 #!/usr/bin/env bash
-# Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+# Copyright 2022 The TensorFlow Authors. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -27,11 +27,14 @@ source tensorflow/lite/micro/tools/ci_build/helper_functions.sh
 TARGET=cortex_m_corstone_300
 TARGET_ARCH=cortex-m55
 OPTIMIZED_KERNEL_DIR=cmsis_nn
+TOOLCHAINS=(gcc armclang)
 
 # TODO(b/143715361): downloading first to allow for parallel builds.
 readable_run make -f tensorflow/lite/micro/tools/make/Makefile CO_PROCESSOR=ethos_u OPTIMIZED_KERNEL_DIR=${OPTIMIZED_KERNEL_DIR} TARGET=${TARGET} TARGET_ARCH=${TARGET_ARCH} third_party_downloads
 
-# Avoid running tests in parallel.
-readable_run make -f tensorflow/lite/micro/tools/make/Makefile clean
-readable_run make -j$(nproc) -f tensorflow/lite/micro/tools/make/Makefile CO_PROCESSOR=ethos_u OPTIMIZED_KERNEL_DIR=${OPTIMIZED_KERNEL_DIR} TARGET=${TARGET} TARGET_ARCH=${TARGET_ARCH} build
-readable_run make -f tensorflow/lite/micro/tools/make/Makefile CO_PROCESSOR=ethos_u OPTIMIZED_KERNEL_DIR=${OPTIMIZED_KERNEL_DIR} TARGET=${TARGET} TARGET_ARCH=${TARGET_ARCH} test
+for TOOLCHAIN in "${TOOLCHAINS[@]}"; do
+  # Avoid running tests in parallel.
+  readable_run make -f tensorflow/lite/micro/tools/make/Makefile clean
+  readable_run make -j$(nproc) -f tensorflow/lite/micro/tools/make/Makefile TOOLCHAIN=${TOOLCHAIN} CO_PROCESSOR=ethos_u OPTIMIZED_KERNEL_DIR=${OPTIMIZED_KERNEL_DIR} TARGET=${TARGET} TARGET_ARCH=${TARGET_ARCH} build
+  readable_run make -f tensorflow/lite/micro/tools/make/Makefile TOOLCHAIN=${TOOLCHAIN} CO_PROCESSOR=ethos_u OPTIMIZED_KERNEL_DIR=${OPTIMIZED_KERNEL_DIR} TARGET=${TARGET} TARGET_ARCH=${TARGET_ARCH} test
+done

tensorflow/lite/micro/tools/make/ethos_u_core_platform_download.sh

@@ -66,10 +66,6 @@ else
 
   LINKER_PATH=${DOWNLOADED_ETHOS_U_CORE_PLATFORM_PATH}/targets/corstone-300
 
-  # Prepend #!cpp to scatter file.
-  SCATTER=${LINKER_PATH}/platform.scatter
-  echo -e "#!cpp\n$(cat ${SCATTER})" > ${SCATTER}
-
   # Run C preprocessor on linker file to get rid of ifdefs and make sure compiler is downloaded first.
   COMPILER=${DOWNLOADS_DIR}/gcc_embedded/bin/arm-none-eabi-gcc
   if [ ! -f ${COMPILER} ]; then
@@ -79,22 +75,8 @@ else
       exit 1
     fi
   fi
-
   ${COMPILER} -E -x c -P -o ${LINKER_PATH}/platform_parsed.ld ${LINKER_PATH}/platform.ld
 
-  # Patch retarget.c so that g++ can find exit symbol.
-  cat <<EOT >> ${DOWNLOADED_ETHOS_U_CORE_PLATFORM_PATH}/targets/corstone-300/retarget.c
-
-#if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6100100)
-#else
-void RETARGET(exit)(int return_code) {
-  RETARGET(_exit)(return_code);
-  while (1) {}
-}
-#endif
-
-EOT
-
 fi
 
 echo "SUCCESS"

tensorflow/lite/micro/tools/make/increase-stack-size-and-switch-DTCM-SRAM.patch

-From 6cd950c461ea56af59c68b15682e3d1e94ce7db8 Mon Sep 17 00:00:00 2001
-From: Hannes Mogensen <hannes.mogensen@arm.com>
-Date: Wed, 25 May 2022 09:30:09 +0200
-Subject: [PATCH] Increase stack size and and change memory allocation from
- DTCM to SRAM
+From 24a382db4fba684a9d6d320cb900eeac7b628837 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?M=C3=A5ns=20Nilsson?= <mans.nilsson@arm.com>
+Date: Wed, 15 Jun 2022 14:00:36 +0200
+Subject: [PATCH] TFLM patch
 
-Change-Id: If414fb875c0bff4940bf072e466068284579e5f6
 ---
- targets/corstone-300/platform.ld | 8 +++-----
- 1 file changed, 3 insertions(+), 5 deletions(-)
+ targets/corstone-300/platform.ld      | 8 +++-----
+ targets/corstone-300/platform.scatter | 5 +++--
+ targets/corstone-300/retarget.c       | 8 ++++++++
+ 3 files changed, 14 insertions(+), 7 deletions(-)
 
 diff --git a/targets/corstone-300/platform.ld b/targets/corstone-300/platform.ld
 index ec58acc..21316a4 100644
@@ -16,11 +16,11 @@ index ec58acc..21316a4 100644
 @@ -75,7 +75,7 @@
    #define ETHOSU_ARENA  1
  #endif
-
+ 
 -__STACK_SIZE = 0x00008000;
 +__STACK_SIZE = 0x00030000;
  __HEAP_SIZE  = 0x00008000;
-
+ 
  MEMORY
 @@ -150,9 +150,6 @@ SECTIONS
      *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
@@ -31,14 +31,14 @@ index ec58acc..21316a4 100644
 -
      KEEP(*(.eh_frame*))
    } > ITCM :rom_exec
-
+ 
 @@ -275,6 +272,7 @@ SECTIONS
      *(network_model_sec)
  #endif
      * (expected_output_data_sec)
 +    *(.rodata*)
    } > DDR :rom_dram
-
+ 
    __eddr_data = ALIGN (16) ;
 @@ -293,7 +291,7 @@ SECTIONS
      *(COMMON)
@@ -46,9 +46,59 @@ index ec58acc..21316a4 100644
      __bss_end__ = .;
 -  } > DTCM :null
 +  } > SRAM :null
-
+ 
    .heap (COPY) :
    {
---
-2.25.1
+diff --git a/targets/corstone-300/platform.scatter b/targets/corstone-300/platform.scatter
+index fab12d1..be5c227 100644
+--- a/targets/corstone-300/platform.scatter
++++ b/targets/corstone-300/platform.scatter
+@@ -1,3 +1,4 @@
++#!cpp
+ /*
+  * Copyright (c) 2019-2021 Arm Limited. All rights reserved.
+  *
+@@ -76,7 +77,7 @@
+ #endif
+ 
+ #ifndef STACK_SIZE
+-#define STACK_SIZE 0x8000
++#define STACK_SIZE 0x20000
+ #endif
+ 
+ #ifndef HEAP_SIZE
+@@ -136,7 +137,6 @@ APP_IMAGE LR_START LR_SIZE
+         ; Make sure reset_handler ends up in root segment, when split across
+         ; ITCM and DTCM
+         startup_ARMCM55.o
+-        .ANY (+RO)
+     }
+ 
+ #if defined(USE_TRUSTZONE) && defined(TRUSTZONE_SECURE)
+@@ -209,6 +209,7 @@ LOAD_REGION_1 DDR_START DDR_SIZE
+         * (input_data_sec)
+         * (expected_output_data_sec)
+         * (output_data_sec)
++        .ANY (+RO)
+     }
+ 
+     #if (ETHOSU_ARENA == 1)
+diff --git a/targets/corstone-300/retarget.c b/targets/corstone-300/retarget.c
+index 4bde44d..8b69295 100644
+--- a/targets/corstone-300/retarget.c
++++ b/targets/corstone-300/retarget.c
+@@ -274,3 +274,11 @@ int ferror(FILE *f) {
+     return EOF;
+ }
+ #endif
++
++#if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6100100)
++#else
++void RETARGET(exit)(int return_code) {
++  RETARGET(_exit)(return_code);
++  while (1) {}
++}
++#endif
+-- 
+2.17.1
 

tensorflow/lite/micro/tools/make/targets/cortex_m_corstone_300_makefile.inc

@@ -97,7 +97,8 @@ ifeq ($(TOOLCHAIN), armclang)
   FLAGS_ARMC = \
     --target=arm-arm-none-eabi \
     -Wno-unused-private-field \
-    -mcpu=$(MCPU_OPTION)
+    -mcpu=$(MCPU_OPTION) \
+    -ffp-mode=full
 
   # Pass comma separated linker options to armlink
   ARMC6_LDFLAGS += -Wl,--strict,--summary_stderr,--info,summarysizes,--map