compile_commands.json support

compiler/commands.nim

@@ -1154,6 +1154,18 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     handleStdinInput(conf)
   of "nilseqs", "nilchecks", "symbol", "taintmode", "cs", "deadcodeelim": warningOptionNoop(switch)
   of "nimmainprefix": conf.nimMainPrefix = arg
+  of "compilecmdsjson":
+    # TODO
+    # processOnOffSwitch(conf, {optCursorInference}, arg, pass, info)
+    conf.compileCommandsJson = true
+  of "projectcompilecmdjson":
+    # TODO
+    # processOnOffSwitch(conf, {optCursorInference}, arg, pass, info)
+    conf.projectCompileCommandJsons = true
+  of "rootcompilecmdsjson":
+    # TODO
+    # processOnOffSwitch(conf, {optCursorInference}, arg, pass, info)
+    conf.copyCompileCommandsJsonToCurDir = true
   else:
     if strutils.find(switch, '.') >= 0: options.setConfigVar(conf, switch, arg)
     else: invalidCmdLineOption(conf, pass, switch, info)

compiler/extccomp.nim

@@ -1003,6 +1003,18 @@ proc callCCompiler*(conf: ConfigRef) =
 
 template hashNimExe(): string = $secureHashFile(os.getAppFilename())
 
+iterator compileCommandsJsonFiles*(conf: ConfigRef): AbsoluteFile =
+  var rf = if conf.projectCompileCommandJsons:
+    ("compile_commands_" & conf.outFile.changeFileExt("json").string).RelativeFile
+  else:
+    "compile_commands".RelativeFile
+
+  yield getNimcacheDir(conf) / rf
+
+  if conf.copyCompileCommandsJsonToCurDir:
+    yield conf.projectPath / rf
+
+
 proc jsonBuildInstructionsFile*(conf: ConfigRef): AbsoluteFile =
   # `outFile` is better than `projectName`, as it allows having different json
   # files for a given source file compiled with different options; it also
@@ -1027,6 +1039,16 @@ type BuildCache = object
   depfiles: seq[(string, string)]
   nimexe: string
 
+proc jsonCompileCommands*(conf: ConfigRef): JsonNode =
+  # ref: https://clang.llvm.org/docs/JSONCompilationDatabase.html
+  result = %*[]
+  for it in conf.toCompile:
+    result.add %*{
+      "file": it.cname.string,
+      "command": getCompileCFileCmd(conf, it),
+      "directory": conf.outDir.string,
+    }
+
 proc writeJsonBuildInstructions*(conf: ConfigRef; deps: StringTableRef) =
   var linkFiles = collect(for it in conf.externalToLink:
     var it = it
@@ -1060,8 +1082,15 @@ proc writeJsonBuildInstructions*(conf: ConfigRef; deps: StringTableRef) =
     if fileExists(bcache.outputFile):
       bcache.outputLastModificationTime = $getLastModificationTime(bcache.outputFile)
   conf.jsonBuildFile = conf.jsonBuildInstructionsFile
+
   conf.jsonBuildFile.string.writeFile(bcache.toJson.pretty)
 
+  if conf.compileCommandsJson:
+    # NOTE: compile_commands.json uses indent of 2 by convention
+    let compileCmds = conf.jsonCompileCommands.pretty(2)
+    for p in conf.compileCommandsJsonFiles:
+      p.writeFile(compileCmds)
+
 proc changeDetectedViaJsonBuildInstructions*(conf: ConfigRef; jsonFile: AbsoluteFile): bool =
   result = false
   if not fileExists(jsonFile) or not fileExists(conf.absOutFile): return true

compiler/options.nim

@@ -448,6 +448,10 @@ type
     currentConfigDir*: string # used for passPP only; absolute dir
     clientProcessId*: int
 
+    compileCommandsJson*: bool
+    projectCompileCommandJsons*: bool
+    copyCompileCommandsJsonToCurDir*: bool
+
 
 
 proc assignIfDefault*[T](result: var T, val: T, def = default(T)) =

tests/compile_commands_json/foo.cpp

@@ -0,0 +1,7 @@
+#include <iostream>
+
+#ifdef ENABLE_FOO
+extern "C" void foo() {
+    std::cout << "hello world\n";
+}
+#endif

tests/compile_commands_json/foo.nim

@@ -0,0 +1,6 @@
+{.compile("foo.cpp", "-DENABLE_FOO").}
+
+proc foo() {.importc.}
+
+when isMainModule:
+  foo()

tests/compile_commands_json/foo.nims

@@ -0,0 +1,2 @@
+--nimcache:"./nimcache"
+--compileCmdsJson:on