Support picolib

.github/workflows/ci.yml

@@ -51,3 +51,5 @@ jobs:
         run: pushd examples; ./build_all.sh || exit; popd
       - name: ci-debug-build
         run: pushd examples/blink; make debug RAM_START=0x20004000 FLASH_INIT=0x30051 || exit; popd
+      - name: ci-build-picolib
+        run: pushd examples/tests/hello_loop; make clean; make PICOLIB=1 || exit; popd

Configuration.mk

@@ -197,6 +197,12 @@ override CPPFLAGS_PIC += \
       -Wl,--emit-relocs\
       -fPIC
 
+ifneq ($(PICOLIB),)
+  # Use picolib for libc. We need to include the `picolib-tock` library which
+  # maps Tock's system-level functions to the names that picolib expects.
+  EXTERN_LIBS += $(TOCK_USERLAND_BASE_DIR)/picolib-tock
+endif
+
 ################################################################################
 ##
 ## RISC-V compiler/linker flags
@@ -256,10 +262,19 @@ else ifeq ($(CC_rv32_version_major),13)
 else
   NEWLIB_VERSION_rv32 := 4.3.0.20230120
 endif
-NEWLIB_VERSION_rv32i    := $(NEWLIB_VERSION_rv32)
-NEWLIB_VERSION_rv32imc  := $(NEWLIB_VERSION_rv32)
-NEWLIB_VERSION_rv32imac := $(NEWLIB_VERSION_rv32)
-NEWLIB_BASE_DIR_rv32 := $(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-$(NEWLIB_VERSION_rv32)
+
+ifeq ($(PICOLIB),)
+  # Use newlib
+  TOCK_LIBC_FOLDER_rv32 := libtock-newlib-$(NEWLIB_VERSION_rv32)
+else
+  # Use picolib
+  TOCK_LIBC_FOLDER_rv32 := libtock-picolib-1.8.5
+endif
+
+TOCK_LIBC_FOLDER_rv32i    := $(TOCK_LIBC_FOLDER_rv32)
+TOCK_LIBC_FOLDER_rv32imc  := $(TOCK_LIBC_FOLDER_rv32)
+TOCK_LIBC_FOLDER_rv32imac := $(TOCK_LIBC_FOLDER_rv32)
+TOCK_LIBC_BASE_DIR_rv32   := $(TOCK_USERLAND_BASE_DIR)/lib/$(TOCK_LIBC_FOLDER_rv32)
 
 # Match compiler version to supported libtock-libc++ versions.
 ifeq ($(CC_rv32_version_major),10)
@@ -299,7 +314,7 @@ override CFLAGS_rv32imac += $(CFLAGS_rv32)
 # Set the base `CPPFLAGS` for all RISC-V variants based on the toolchain family.
 override CPPFLAGS_rv32 += \
       $(CPPFLAGS_toolchain_rv32) \
-      -isystem $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include \
+      -isystem $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include \
       -isystem $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include/c++/$(LIBCPP_VERSION_rv32) \
       -isystem $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include/c++/$(LIBCPP_VERSION_rv32)/riscv64-unknown-elf
 
@@ -330,26 +345,26 @@ override WLFLAGS_rv32imc  += $(WLFLAGS_rv32)
 override WLFLAGS_rv32imac += $(WLFLAGS_rv32)
 
 override SYSTEM_LIBS_rv32i    += \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libc.a \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libm.a
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libc.a \
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libm.a
 
 override SYSTEM_LIBS_CXX_rv32i += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libstdc++.a \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libsupc++.a \
       $(LIBCPP_BASE_DIR_rv32)/riscv/lib/gcc/riscv64-unknown-elf/$(LIBCPP_VERSION_rv32)/rv32i/ilp32/libgcc.a
 
 override SYSTEM_LIBS_rv32imc  += \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libc.a \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libm.a
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libc.a \
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libm.a
 
 override SYSTEM_LIBS_CXX_rv32imc += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libstdc++.a \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libsupc++.a \
       $(LIBCPP_BASE_DIR_rv32)/riscv/lib/gcc/riscv64-unknown-elf/$(LIBCPP_VERSION_rv32)/rv32im/ilp32/libgcc.a
 
 override SYSTEM_LIBS_rv32imac += \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libc.a \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libm.a
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libc.a \
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libm.a
 
 override SYSTEM_LIBS_CXX_rv32imac += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libstdc++.a \
@@ -396,11 +411,20 @@ else ifeq ($(CC_cortex-m_version_major),13)
 else
   NEWLIB_VERSION_cortex-m := 4.3.0.20230120
 endif
-NEWLIB_VERSION_cortex-m0 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_VERSION_cortex-m3 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_VERSION_cortex-m4 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_VERSION_cortex-m7 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_BASE_DIR_cortex-m := $(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-$(NEWLIB_VERSION_cortex-m)
+
+ifeq ($(PICOLIB),)
+  # Use newlib
+  TOCK_LIBC_FOLDER_cortex-m := libtock-newlib-$(NEWLIB_VERSION_cortex-m)
+else
+  # Use picolib
+  TOCK_LIBC_FOLDER_cortex-m := libtock-picolib-1.8.5
+endif
+
+TOCK_LIBC_FOLDER_cortex-m0  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_FOLDER_cortex-m3  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_FOLDER_cortex-m4  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_FOLDER_cortex-m7  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_BASE_DIR_cortex-m := $(TOCK_USERLAND_BASE_DIR)/lib/$(TOCK_LIBC_FOLDER_cortex-m)
 
 # Match compiler version to supported libtock-libc++ versions.
 ifeq ($(CC_cortex-m_version_major),10)
@@ -441,7 +465,7 @@ override CPPFLAGS_cortex-m += \
       -msingle-pic-base\
       -mpic-register=r9\
       -mno-pic-data-is-text-relative\
-      -isystem $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/include\
+      -isystem $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/include\
       -isystem $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/include/c++/$(LIBCPP_VERSION_cortex-m)\
       -isystem $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/include/c++/$(LIBCPP_VERSION_cortex-m)/arm-none-eabi
 
@@ -460,35 +484,35 @@ override CPPFLAGS_cortex-m7 += $(CPPFLAGS_cortex-m) \
       -mcpu=cortex-m7
 
 override SYSTEM_LIBS_cortex-m0 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m0 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libstdc++.a \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libsupc++.a \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/lib/gcc/arm-none-eabi/$(LIBCPP_VERSION_cortex-m)/thumb/v6-m/nofp/libgcc.a
 
 override SYSTEM_LIBS_cortex-m3 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m3 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libstdc++.a \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libsupc++.a \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/lib/gcc/arm-none-eabi/$(LIBCPP_VERSION_cortex-m)/thumb/v7-m/nofp/libgcc.a
 
 override SYSTEM_LIBS_cortex-m4 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m4 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libstdc++.a \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libsupc++.a \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/lib/gcc/arm-none-eabi/$(LIBCPP_VERSION_cortex-m)/thumb/v7e-m/nofp/libgcc.a
 
 override SYSTEM_LIBS_cortex-m7 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m7 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libstdc++.a \

Precompiled.mk

@@ -44,8 +44,8 @@ RISCV_ARCHS := rv32i/ilp32 rv32im/ilp32 rv32imac/ilp32
 # - $(3): Arch
 define PRECOMPILED_NEWLIB_RULES
 
-TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/%/$(1)/$(2)/lib/$(3)/libc.a
-TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/%/$(1)/$(2)/lib/$(3)/libm.a
+TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-%/$(1)/$(2)/lib/$(3)/libc.a
+TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-%/$(1)/$(2)/lib/$(3)/libm.a
 
 endef
 
@@ -55,10 +55,45 @@ $(foreach arch,$(RISCV_ARCHS),$(eval $(call PRECOMPILED_NEWLIB_RULES,riscv,riscv
 
 # Target to download and extract newlib.
 #
-# % will match something like "libtock-newlib-4.2.0.20211231" which we then
-# strip down to just the version with some string manipulation.
+# `$*` will match the version number in the libtock-newlib folder name
+# (something like "libtock-newlib-4.2.0.20211231").
 $(TOCK_NEWLIB_TARGETS):
-	cd $(TOCK_USERLAND_BASE_DIR)/lib; ./fetch-newlib.sh $(patsubst libtock-newlib-%,%,$*)
+	cd $(TOCK_USERLAND_BASE_DIR)/lib; ./fetch-newlib.sh $*
+
+################################################################################
+# Picolib Rules
+#
+# These pre-compiled archives were created using the libtock-c/picolib folder.
+################################################################################
+
+# Rule to ensure that the picolib libraries for an architecture exist.
+#
+# Need to list all libraries which are possible targets into one variable. It is
+# imperative that the wildcard `%` expands to the same value for every target to
+# tell make that one invocation of this build rule will make all the target
+# files.
+#
+# Arguments:
+# - $(1): Family
+# - $(2): Toolchain
+# - $(3): Arch
+define PRECOMPILED_PICOLIB_RULES
+
+TOCK_PICOLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-picolib-%/$(1)/$(2)/lib/$(3)/libc.a
+TOCK_PICOLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-picolib-%/$(1)/$(2)/lib/$(3)/libm.a
+
+endef
+
+TOCK_PICOLIB_TARGETS :=
+$(foreach arch,$(ARM_ARCHS),$(eval $(call PRECOMPILED_PICOLIB_RULES,arm,arm-none-eabi,$(arch))))
+$(foreach arch,$(RISCV_ARCHS),$(eval $(call PRECOMPILED_PICOLIB_RULES,riscv,riscv64-unknown-elf,$(arch))))
+
+# Target to download and extract picolib.
+#
+# `$*` will match the version number in the libtock-picolib folder name
+# (something like "libtock-picolib-1.8.5").
+$(TOCK_PICOLIB_TARGETS):
+	cd $(TOCK_USERLAND_BASE_DIR)/lib; ./fetch-picolib.sh $*
 
 ################################################################################
 # LIBC++ Rules
@@ -75,7 +110,7 @@ TOCK_CXXLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/%/$(1)/$(2)/lib/$(3)/libsu
 # So this is supremely frustrating. The issue boils down to limitations of
 # pattern rules in make.
 #
-# First: pattern rules are implicitly groups, and you aren't allowed to 
+# First: pattern rules are implicitly groups, and you aren't allowed to
 # use the :g operator to merge groups. What this means in practice is that
 # if you have many targets that are all generated by the same rule (i.e.,
 # our unzip creates all the library archive targets), all of the targets

lib/fetch-picolib.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+PICOLIB_VERSION=$1
+
+if [ $PICOLIB_VERSION = "1.8.5" ]; then
+  PICOLIB_SHA="5168a7ea6522717ec5867e0105a224fe7e3779371b095deedc2cd58da369d8cc"
+fi
+
+# Name of the pre-created compiled directories.
+ZIP_FILE=libtock-picolib-$PICOLIB_VERSION.zip
+
+# List of mirrors we support.
+MIRRORS=(\
+  "https://www.cs.virginia.edu/~bjc8c/archive/tock"\
+  "https://alpha.mirror.svc.schuermann.io/files"\
+)
+
+let FOUND=0
+
+# Try from each mirror until we successfully download a .zip file.
+for MIRROR in ${MIRRORS[@]}; do
+  URL=$MIRROR/$ZIP_FILE
+  echo "Fetching picolib from ${MIRROR}..."
+  echo "  Fetching ${URL}..."
+  wget -q "$URL" && (echo "$PICOLIB_SHA $ZIP_FILE" | sha256sum -c)
+  if [ $? -ne 0 ]; then
+    echo "  WARNING: Fetching picolib from mirror $MIRROR failed!" >&2
+  else
+    let FOUND=1
+    break
+  fi
+done
+
+if [[ $FOUND -ne 0 ]]; then
+  unzip $ZIP_FILE
+else
+  echo "ERROR: Unable to find tock-picolib"
+  exit -1
+fi

libtock-sync/sys.c

@@ -1,5 +1,7 @@
 #include "interface/console.h"
 
+#include "tock_sys.h"
+
 // XXX Suppress missing prototype warnings for this file as the headers should
 // be in newlib internals, but first stab at including things didn't quite work
 // and the warnings are just noise
@@ -11,8 +13,6 @@
 // SYNCHRONOUS LIBC SUPPORT STUBS
 // ------------------------------
 
-int _write(__attribute__ ((unused)) int fd, const void* buf, uint32_t count) {
-  int written;
-  libtocksync_console_write((const uint8_t*) buf, count, &written);
-  return written;
+int _write(int fd, const void* buf, uint32_t count) {
+  return _tock_write(fd, buf, count);
 }

libtock-sync/tock_sys.c

@@ -0,0 +1,18 @@
+#include "interface/console.h"
+
+// XXX Suppress missing prototype warnings for this file as the headers should
+// be in newlib internals, but first stab at including things didn't quite work
+// and the warnings are just noise
+#pragma GCC diagnostic ignored "-Wmissing-declarations"
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+#pragma GCC diagnostic ignored "-Wstrict-prototypes"
+
+// ------------------------------
+// SYNCHRONOUS LIBC SUPPORT STUBS
+// ------------------------------
+
+int _tock_write(__attribute__ ((unused)) int fd, const void* buf, uint32_t count) {
+  int written;
+  libtocksync_console_write((const uint8_t*) buf, count, &written);
+  return written;
+}

libtock-sync/tock_sys.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int _tock_write(int fd, const void* buf, uint32_t count);
+
+#ifdef __cplusplus
+}
+#endif

libtock/sys.c

@@ -4,6 +4,7 @@
 
 #include "interface/console.h"
 #include "tock.h"
+#include "tock_sys.h"
 
 // XXX Suppress unused parameter warnings for this file as the implementations
 // are currently all just stubs
@@ -28,29 +29,9 @@ void* __dso_handle = 0;
 int _unlink(const char* pathname) {
   return -1;
 }
-
-int _isatty(int fd) {
-  if (fd == 0) {
-    return 1;
-  }
-  return 0;
-}
 int _open(const char* path, int flags, ...) {
   return -1;
 }
-int _close(int fd) {
-  return -1;
-}
-int _fstat(int fd, struct stat* st) {
-  st->st_mode = S_IFCHR;
-  return 0;
-}
-int _lseek(int fd, uint32_t offset, int whence) {
-  return 0;
-}
-int _read(int fd, void* buf, uint32_t count) {
-  return 0;   // k_read(fd, (uint8_t*) buf, count);
-}
 void _exit(int __status) {
   tock_exit((uint32_t) __status);
 }
@@ -61,12 +42,22 @@ int _kill(pid_t pid, int sig) {
   return -1;
 }
 
+// FOR NEWLIB
+int _fstat(int fd, struct stat* st) {
+  return _tock_fstat(fd, st);
+}
+int _isatty(int fd) {
+  return _tock_isatty(fd);
+}
+int _read(int fd, void* buf, uint32_t count) {
+  return _tock_read(fd, buf, count);
+}
+int _lseek(int fd, uint32_t offset, int whence) {
+  return _tock_lseek(fd, offset, whence);
+}
+int _close(int fd) {
+  return _tock_close(fd);
+}
 caddr_t _sbrk(int incr) {
-  memop_return_t ret;
-  ret = memop(1, incr);
-  if (ret.status != TOCK_STATUSCODE_SUCCESS) {
-    errno = ENOMEM;
-    return (caddr_t) -1;
-  }
-  return (caddr_t) ret.data;
+  return _tock_sbrk(incr);
 }