Zephyr: Move from newlibc to picolibc

core/src/main/java/org/lflang/generator/c/CCmakeGenerator.java

@@ -317,9 +317,11 @@ CodeBuilder generateCMakeCode(
     }
     cMakeCode.newLine();
 
-    // Add the install option
-    cMakeCode.pr(installCode);
-    cMakeCode.newLine();
+    // Add the install option. Unless we are targeting Zephyr
+    if (targetConfig.platformOptions.platform != Platform.ZEPHYR) {
+      cMakeCode.pr(installCode);
+      cMakeCode.newLine();
+    }
 
     // Add the include file
     for (String includeFile : targetConfig.cmakeIncludes) {

core/src/main/java/org/lflang/generator/c/CCompiler.java

@@ -150,7 +150,12 @@ public boolean runCCompiler(GeneratorBase generator, LFGeneratorContext context)
     int makeReturnCode = 0;
 
     if (cMakeReturnCode == 0) {
-      LFCommand build = buildCmakeCommand();
+      LFCommand build;
+      if (targetConfig.platformOptions.platform == Platform.ZEPHYR) {
+        build = buildCmakeZephyrCommand();
+      } else {
+        build = buildCmakeCommand();
+      }
 
       makeReturnCode = build.run(context.getCancelIndicator());
 
@@ -308,6 +313,36 @@ public LFCommand buildCmakeCommand() {
     return command;
   }
 
+  /**
+   * @return A command to build a file with CMake when the platform is Zephyr. This is identical to
+   *     the normal command except we dont use --target install.
+   */
+  public LFCommand buildCmakeZephyrCommand() {
+    // Set the build directory to be "build"
+    Path buildPath = fileConfig.getSrcGenPath().resolve("build");
+    String cores = String.valueOf(Runtime.getRuntime().availableProcessors());
+    LFCommand command =
+        commandFactory.createCommand(
+            "cmake",
+            List.of(
+                "--build",
+                ".",
+                "--parallel",
+                cores,
+                "--config",
+                buildTypeToCmakeConfig(targetConfig.cmakeBuildType)),
+            buildPath);
+    if (command == null) {
+      messageReporter
+          .nowhere()
+          .error(
+              "The C/CCpp target requires CMAKE >= 3.5 to compile the generated code."
+                  + " Auto-compiling can be disabled using the \"no-compile: true\" target"
+                  + " property.");
+    }
+    return command;
+  }
+
   /**
    * Return a flash/emulate command using west. If board is null (defaults to qemu_cortex_m3) or
    * qemu_* Return a flash command which runs the target as an emulation If ordinary target, return

core/src/main/resources/lib/platform/zephyr/prj_lf.conf

@@ -7,8 +7,15 @@
 
 # Enable printf
 CONFIG_PRINTK=y
-# Use the newlib C library
-CONFIG_NEWLIB_LIBC=y
-CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
+# Use the picolib C library. This is used instead of newlib because it also
+# supports regexp used by federate.c
+CONFIG_PICOLIBC=y
+CONFIG_PICOLIBC_IO_FLOAT=y
+CONFIG_PICOLIBC_IO_C99_FORMATS=y
+CONFIG_PICOLIBC_IO_LONG_LONG=y
+
+# To get `read`, `write`, `lseek` and `close` used by tracing infrastructure.
+CONFIG_FILE_SYSTEM=y
+
 # Enable the counter API used for hi-res clock
 CONFIG_COUNTER=y

test/C/src/TestForPreviousOutput.lf

@@ -17,7 +17,7 @@ reactor Source {
 
   reaction(startup) -> out {=
     // Set a seed for random number generation based on the current time.
-    srand(time(0));
+    srand(lf_time_physical());
     // Randomly produce an output or not.
     if (rand() % 2) {
       lf_set(out, 21);