Merge pull request #267 from r-devel/feature/lldb-new

Feature : Enable LLDB Debugging for R Dev Container

Author: hturner

.Rprofile

@@ -9,6 +9,10 @@
 # .libPaths() already includes site library for default R version.
 .libPaths(c(.libPaths(), .Library.site))
 
+# Source initialization script for VSCode R extension
+source("~/.vscode-R/init.R")
+.First.sys()
+
 # The remotes package is installed to install httpgd from GitHub
 # The gdiff package is installed to support visual difference testing
 

.devcontainer/devcontainer.json

@@ -1,6 +1,7 @@
 {
     "name": "R-Dev-Env",
     "image": "ghcr.io/r-devel/r-dev-env:devel",
+    "runArgs": ["--cap-add=SYS_PTRACE"],
     "remoteUser": "vscode",
     "hostRequirements": {
         "cpus": 4
@@ -10,7 +11,6 @@
             "settings": {
                 "git.ignoredRepositories": ["."],
                   "files.exclude": {
-                       "**/.vscode": true,
                        "**/.devcontainer": true,
                        "**/.git": true,
                        "**/.github": true,
@@ -44,9 +44,10 @@
                 "johnstoncode.svn-scm",
                 "ms-vscode.cpptools",
                 "MS-vsliveshare.vsliveshare",
-                "natqe.reload"
+                "natqe.reload",
+                "vadimcn.vscode-lldb"
             ]
         }
     },
-    "postCreateCommand": "sh /workspaces/r-dev-env/scripts/localscript.sh"
+    "postCreateCommand": "bash ./scripts/localscript.sh"
 }

.devcontainer/launch.json

@@ -0,0 +1,12 @@
+{
+"version": "0.2.0",
+"configurations": [
+    {
+      "name": "(lldb) Attach to R",
+      "type": "lldb",
+      "request": "attach",
+      "pid": "${command:pickMyProcess}",
+      "stopOnEntry": false
+    }
+  ]
+}

.gitignore

@@ -1,8 +1,9 @@
-R-4.1.3/
-R-4.1.3.tar.gz
-R-devel/
-R-devel.tar.gz
+/build
+/svn
 /venv
 .cache/
-.Rproj.user
 .vscode/
+.Rhistory
+.Rproj.user
+*.Rproj
+*/allow_ptrace

INIT

@@ -61,8 +61,7 @@ cd $BUILDDIR
 directory.  This step takes ~1 minute on the codespace.
 
 ```bash
-$TOP_SRCDIR/configure --with-valgrind-instrumentation=1
-
+$TOP_SRCDIR/configure --with-valgrind-instrumentation=1 CFLAGS="-g -O0"
 ```
 
 <!-- markdownlint-disable MD046 -->
@@ -71,6 +70,9 @@ $TOP_SRCDIR/configure --with-valgrind-instrumentation=1
     of valgrind. See the [Using
     valgrind](https://cran.r-project.org/doc/manuals/R-exts.html#Using-valgrind)
     section of the R-admin manual for more information.
+    The `CFLAGS="-g -O0"` setting compiles C code with debugging symbols
+    (`-g`) and disables optimization (`-O0`) so the compiled code closely
+    matches the original source, which aids debugging.
 <!-- markdownlint-enable MD046 -->
 
 - The configure cmd prepares for building R, creating files and folders inside

docs/tutorials/building_r.md

@@ -0,0 +1,16 @@
+#include <sys/prctl.h>
+#include <unistd.h>
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+    if (argc < 2) {
+        fprintf(stderr, "usage: %s <path-to-R> [args...]\n", argv[0]);
+        return 2;
+    }
+    /* allow ptrace for this process (persists across exec) */
+    prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY);
+    /* exec the provided R binary with the remaining args */
+    execv(argv[1], &argv[1]);
+    perror("execv");
+    return 1;
+}

scripts/allow_ptrace.c

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+# `which_r.sh` sets the R binary used in the command below
+exec ./scripts/allow_ptrace /usr/bin/R "$@"

scripts/launch_r.sh

@@ -27,11 +27,28 @@ cat $WORK_DIR/scripts/welcome_msg.sh >> ~/.bashrc
 # Remove git directory if it exists
 #rm -rf .git
 
+# copy launch.json for debugging config if present
+if [ -f "$WORK_DIR/.devcontainer/launch.json" ]; then
+    cp "$WORK_DIR/.devcontainer/launch.json" "$VSCODE_DIR/launch.json"
+fi
+
 # copying vscode extension settings from devcontainer json to vscode settings json using jq
 if [ -f "$DEVCONTAINER_JSON" ]; then
         jq '.customizations.vscode.settings' "$DEVCONTAINER_JSON" > "$VSCODE_DIR/settings.json"
 fi
 
+# Update r.rterm.linux setting to use the launch_r.sh script with full dynamic path
+if [ -f "$VSCODE_DIR/settings.json" ]; then
+    tmpfile="${VSCODE_DIR/settings.json}.tmp.$$"
+    jq --arg rterm "$WORK_DIR/scripts/launch_r.sh" '."r.rterm.linux"=$rterm' "$VSCODE_DIR/settings.json" > "$tmpfile" && mv "$tmpfile" "$VSCODE_DIR/settings.json"
+fi
+
+# Compile the ptrace helper executable
+gcc -O2 -o "$WORK_DIR/scripts/allow_ptrace" "$WORK_DIR/scripts/allow_ptrace.c"
+chmod +x "$WORK_DIR/scripts/allow_ptrace"
+
+# Mark the wrapper executable
+chmod +x "$WORK_DIR/scripts/launch_r.sh"
 
 }
 

scripts/localscript.sh

@@ -28,9 +28,8 @@ PATCHDIR = \"$PATCHDIR\"
 Have fun \U0001F601
 "
 
-# open INDEX.md if INIT file exists
+# open INDEX.md if svn and build directories do not exist
 if [ ! -d "svn" ] && [ ! -d "build" ]; then
     sleep 2
     code INDEX.md
-    rm INIT
 fi