lib picolib: add build scripts

Author: bradjc

picolib/.gitignore

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+libtock-picolib*
+picolib-*
+picolibc-*

picolib/Makefile

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+all: rebuild-picolib
+
+ifeq ($(PICOLIB_VERSION),)
+  $(error Need to set the PICOLIB_VERSION variable to choose which to build.)
+endif
+
+picolib-$(PICOLIB_VERSION).tar.xz:
+	@echo "Downloading picolib source $(@F)"
+	@wget -q -O $@ https://github.com/picolibc/picolibc/releases/download/$(PICOLIB_VERSION)/picolibc-$(PICOLIB_VERSION).tar.xz
+
+picolibc-$(PICOLIB_VERSION): picolib-$(PICOLIB_VERSION).tar.xz
+	@echo "Extracting $(<F)"
+	@tar -xzf $<
+	@touch $@ # Touch so directory appears newer than tarball
+
+rebuild-picolib: picolibc-$(PICOLIB_VERSION)
+	@rm -rf picolib-arm-$(PICOLIB_VERSION)-out
+	@rm -rf picolib-arm-$(PICOLIB_VERSION)-install
+	@rm -rf picolib-riscv-$(PICOLIB_VERSION)-out
+	@rm -rf picolib-riscv-$(PICOLIB_VERSION)-install
+	@rm -rf libtock-picolib-$(PICOLIB_VERSION).zip
+	@rm -rf libtock-picolib-$(PICOLIB_VERSION)
+	@echo ""
+	@echo "=== BEGINNING ARM BUILD =========================="
+	@echo ""
+	@mkdir -p picolib-arm-$(PICOLIB_VERSION)-out
+	@mkdir -p picolib-arm-$(PICOLIB_VERSION)-install
+	@echo "Entering directory picolib-arm-$(PICOLIB_VERSION)-out"
+	cd picolib-arm-$(PICOLIB_VERSION)-out; ../build-arm.sh ../$< ../picolib-arm-$(PICOLIB_VERSION)-install | tee build-arm.log
+	@echo ""
+	@echo "=== BEGINNING RISC-V BUILD ======================="
+	@echo ""
+	@mkdir -p picolib-riscv-$(PICOLIB_VERSION)-out
+	@mkdir -p picolib-riscv-$(PICOLIB_VERSION)-install
+	@echo "Entering directory picolib-riscv-$(PICOLIB_VERSION)-out"
+	cd picolib-riscv-$(PICOLIB_VERSION)-out; ../build-riscv.sh ../$< ../picolib-riscv-$(PICOLIB_VERSION)-install | tee build-riscv.log
+	@echo ""
+	@echo "=== PACKAGING PICOLIB ARTIFACTS ==================="
+	@echo ""
+	@mkdir -p libtock-picolib-$(PICOLIB_VERSION)/arm
+	@mkdir -p libtock-picolib-$(PICOLIB_VERSION)/riscv
+	@cp -r picolib-arm-$(PICOLIB_VERSION)-install/picolibc/arm-none-eabi libtock-picolib-$(PICOLIB_VERSION)/arm
+	@cp -r picolib-riscv-$(PICOLIB_VERSION)-install/picolibc/riscv64-unknown-elf libtock-picolib-$(PICOLIB_VERSION)/riscv
+	@mv picolib-arm-$(PICOLIB_VERSION)-out/build-arm.log picolib-riscv-$(PICOLIB_VERSION)-out/build-riscv.log libtock-picolib-$(PICOLIB_VERSION)
+	@zip -r libtock-picolib-$(PICOLIB_VERSION).zip libtock-picolib-$(PICOLIB_VERSION)
+	@echo ""
+	@echo "=== FINISHED PICOLIB ZIP =========================="
+	@echo ""
+	@sha256sum libtock-picolib-$(PICOLIB_VERSION).zip

picolib/README.md

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+Tock Userland libc  - Picolibc
+==============================
+
+[Picolibc](https://github.com/picolibc/picolibc) is a port of the C standard
+library designed for embedded systems. Tock uses a version of Picolibc compiled
+to support the position independent code that Tock applications require.
+
+Compiling a new version of Picolibc
+-----------------------------------
+
+This folder contains scripts to build and package picolibc for libtock-c.
+
+### Simple Directions
+
+If you want to build and package picolibc locally you can use the provided
+`Makefile`.
+
+You must choose by setting the variable `PICOLIB_VERSION` with the version you
+want to compile. The releases are listed
+[here](https://github.com/picolibc/picolibc/releases).
+
+Then:
+
+    $ make PICOLIB_VERSION=1.8.5
+
+When the build finishes (it takes a while), a zip folder named
+`libtock-picolib-<version>.zip` will contain the built libraries. You can move
+that folder to the `libtock-c/lib` directory to use the new version of newlib.
+
+### Docker
+
+To help with reproducibility, we provide Dockerfiles for various versions of
+newlib that can generate the compiled version of libtock-picolib.
+
+```bash
+cd docker/docker-picolib-<version>
+./docker-create.sh
+```

picolib/build-arm.sh

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+#!/usr/bin/env bash
+
+set -x
+
+PICOLIB_SRC_DIR=$1
+PICOLIB_INSTALL_DIR=$2
+
+# We want to end up with newlib compiled for at least the `v6-m/nofp`,
+# `v7-m/nofp`, and `v7e-m/nofp` architectures. For that to happen the
+# arm-none-eabi-gcc compiler must have been compiled with multilib support for
+# those architectures. We verify that here before actually building anything.
+if ! arm-none-eabi-gcc --print-multi-lib | grep -q 'v6-m/nofp'; then
+  echo "ERROR: arm-none-eabi-gcc not configured with multilib support for v6-m/nofp"
+  exit -1
+fi
+if ! arm-none-eabi-gcc --print-multi-lib | grep -q 'v7-m/nofp'; then
+  echo "ERROR: arm-none-eabi-gcc not configured with multilib support for v7-m/nofp"
+  exit -1
+fi
+if ! arm-none-eabi-gcc --print-multi-lib | grep -q 'v7e-m/nofp'; then
+  echo "ERROR: arm-none-eabi-gcc not configured with multilib support for v7e-m/nofp"
+  exit -1
+fi
+
+# Picolibc Configure Flags
+#
+# picolib=false             # Do not use picolib sbrk. We need to use the memop syscalls.
+# picocrt=false             # Do not build crt0, we have our own.
+# picocrt-lib=false         # Do not package crt0.
+# tinystdio=false           # Do not use AVR tinystdio, which uses a different underlying interface (aka stdout object).
+# newlib-stdio64=false      # Do not include 64 bit APIs.
+# newlib-reent-small=true   # ?
+# newlib-global-atexit=true # ?
+$PICOLIB_SRC_DIR/scripts/do-configure arm-none-eabi -Dprefix=`realpath $PICOLIB_INSTALL_DIR` \
+  -Dpicolib=false \
+  -Dpicocrt=false \
+  -Dpicocrt-lib=false \
+  -Dtinystdio=false \
+  -Dnewlib-stdio64=false \
+  -Dnewlib-reent-small=true \
+  -Dnewlib-global-atexit=true \
+  -Dmultilib-list=thumb/v6-m/nofp,thumb/v7-m/nofp,thumb/v7e-m/nofp \
+  -Dc_args="-g -Os -ffunction-sections -fdata-sections -fPIC -msingle-pic-base -mno-pic-data-is-text-relative"
+
+ninja
+ninja install

picolib/build-riscv.sh

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+#!/usr/bin/env bash
+
+set -x
+
+PICOLIB_SRC_DIR=$1
+PICOLIB_INSTALL_DIR=$2
+
+$PICOLIB_SRC_DIR/scripts/do-configure riscv64-unknown-elf -Dprefix=`realpath $PICOLIB_INSTALL_DIR` \
+  -Dpicolib=false \
+  -Dpicocrt=false \
+  -Dpicocrt-lib=false \
+  -Dtinystdio=false \
+  -Dnewlib-stdio64=false \
+  -Dmultilib-list=rv32i/ilp32,rv32im/ilp32,rv32imac/ilp32 \
+  -Dnewlib-reent-small=true \
+  -Dnewlib-global-atexit=true
+
+ninja
+ninja install

picolib/docker/docker-picolib-1.8.5/Dockerfile

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+###
+### Dockerfile to build libtock-picolib-1.8.5
+###
+
+# We get version 12 of arm-none-eabi-gcc/riscv64-unknown-elf-gcc.
+FROM debian:bookworm
+
+LABEL maintainer="Tock Project Developers <[email protected]>"
+LABEL version="0.1"
+LABEL description="Dockerfile to build libtock-c picolib 1.8.5."
+
+# Disable Prompt During Packages Installation
+ARG DEBIAN_FRONTEND=noninteractive
+# Update Ubuntu Software repository
+RUN apt update
+
+# Install our toolchains
+RUN apt install -y gcc-arm-none-eabi gcc-riscv64-unknown-elf
+
+# Install needed tools
+RUN apt install -y git build-essential ninja-build meson zip
+
+# Clone the libtock-c source so we can use the build scripts
+RUN git clone https://github.com/tock/libtock-c -b make-precompiled-picolib
+RUN cd libtock-c && git fetch && git checkout 6dc8907938e7daa307650ba6577a59c25214ef3f
+
+# Actually build the toolchain
+RUN cd libtock-c/picolib && make PICOLIB_VERSION=1.8.5

picolib/docker/docker-picolib-1.8.5/docker-create.sh

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+#!/usr/bin/env bash
+
+docker build -t libtock-c-picolib-1.8.5 .
+id=$(docker create libtock-c-picolib-1.8.5)
+docker cp $id:/libtock-c/newlib/libtock-picolib-1.8.5.zip libtock-picolib-1.8.5.zip