make Nim take roughly 100MB less RAM for bootstrapping via a new compiler switch -d:leanCompiler; useful for the Raberry PI

compiler/main.nim

@@ -15,12 +15,15 @@ when not defined(nimcore):
 import
   llstream, strutils, ast, astalgo, lexer, syntaxes, renderer, options, msgs,
   os, condsyms, times,
-  wordrecg, sem, semdata, idents, passes, docgen, extccomp,
-  cgen, jsgen, json, nversion,
+  wordrecg, sem, semdata, idents, passes, extccomp,
+  cgen, json, nversion,
   platform, nimconf, importer, passaux, depends, vm, vmdef, types, idgen,
-  docgen2, parser, modules, ccgutils, sigmatch, ropes,
+  parser, modules, ccgutils, sigmatch, ropes,
   modulegraphs, tables, rod, lineinfos, pathutils
 
+when not defined(leanCompiler):
+  import jsgen, docgen, docgen2
+
 from magicsys import resetSysTypes
 
 proc codegenPass(g: ModuleGraph) =
@@ -57,13 +60,14 @@ proc commandCheck(graph: ModuleGraph) =
   semanticPasses(graph)  # use an empty backend for semantic checking only
   compileProject(graph)
 
-proc commandDoc2(graph: ModuleGraph; json: bool) =
-  graph.config.errorMax = high(int)  # do not stop after first error
-  semanticPasses(graph)
-  if json: registerPass(graph, docgen2JsonPass)
-  else: registerPass(graph, docgen2Pass)
-  compileProject(graph)
-  finishDoc2Pass(graph.config.projectName)
+when not defined(leanCompiler):
+  proc commandDoc2(graph: ModuleGraph; json: bool) =
+    graph.config.errorMax = high(int)  # do not stop after first error
+    semanticPasses(graph)
+    if json: registerPass(graph, docgen2JsonPass)
+    else: registerPass(graph, docgen2Pass)
+    compileProject(graph)
+    finishDoc2Pass(graph.config.projectName)
 
 proc commandCompileToC(graph: ModuleGraph) =
   let conf = graph.config
@@ -84,15 +88,16 @@ proc commandJsonScript(graph: ModuleGraph) =
   let proj = changeFileExt(graph.config.projectFull, "")
   extccomp.runJsonBuildInstructions(graph.config, proj)
 
-proc commandCompileToJS(graph: ModuleGraph) =
-  #incl(gGlobalOptions, optSafeCode)
-  setTarget(graph.config.target, osJS, cpuJS)
-  #initDefines()
-  defineSymbol(graph.config.symbols, "ecmascript") # For backward compatibility
-  defineSymbol(graph.config.symbols, "js")
-  semanticPasses(graph)
-  registerPass(graph, JSgenPass)
-  compileProject(graph)
+when not defined(leanCompiler):
+  proc commandCompileToJS(graph: ModuleGraph) =
+    #incl(gGlobalOptions, optSafeCode)
+    setTarget(graph.config.target, osJS, cpuJS)
+    #initDefines()
+    defineSymbol(graph.config.symbols, "ecmascript") # For backward compatibility
+    defineSymbol(graph.config.symbols, "js")
+    semanticPasses(graph)
+    registerPass(graph, JSgenPass)
+    compileProject(graph)
 
 proc interactivePasses(graph: ModuleGraph) =
   initDefines(graph.config.symbols)
@@ -177,49 +182,76 @@ proc mainCommand*(graph: ModuleGraph) =
     else:
       rawMessage(conf, errGenerated, "'run' command not available; rebuild with -d:tinyc")
   of "js", "compiletojs":
-    conf.cmd = cmdCompileToJS
-    commandCompileToJS(graph)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with JS code generator"
+    else:
+      conf.cmd = cmdCompileToJS
+      commandCompileToJS(graph)
   of "doc0":
-    wantMainModule(conf)
-    conf.cmd = cmdDoc
-    loadConfigs(DocConfig, cache, conf)
-    commandDoc(cache, conf)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      wantMainModule(conf)
+      conf.cmd = cmdDoc
+      loadConfigs(DocConfig, cache, conf)
+      commandDoc(cache, conf)
   of "doc2", "doc":
-    conf.cmd = cmdDoc
-    loadConfigs(DocConfig, cache, conf)
-    defineSymbol(conf.symbols, "nimdoc")
-    commandDoc2(graph, false)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      conf.cmd = cmdDoc
+      loadConfigs(DocConfig, cache, conf)
+      defineSymbol(conf.symbols, "nimdoc")
+      commandDoc2(graph, false)
   of "rst2html":
-    conf.cmd = cmdRst2html
-    loadConfigs(DocConfig, cache, conf)
-    commandRst2Html(cache, conf)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      conf.cmd = cmdRst2html
+      loadConfigs(DocConfig, cache, conf)
+      commandRst2Html(cache, conf)
   of "rst2tex":
-    conf.cmd = cmdRst2tex
-    loadConfigs(DocTexConfig, cache, conf)
-    commandRst2TeX(cache, conf)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      conf.cmd = cmdRst2tex
+      loadConfigs(DocTexConfig, cache, conf)
+      commandRst2TeX(cache, conf)
   of "jsondoc0":
-    wantMainModule(conf)
-    conf.cmd = cmdDoc
-    loadConfigs(DocConfig, cache, conf)
-    wantMainModule(conf)
-    defineSymbol(conf.symbols, "nimdoc")
-    commandJson(cache, conf)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      wantMainModule(conf)
+      conf.cmd = cmdDoc
+      loadConfigs(DocConfig, cache, conf)
+      wantMainModule(conf)
+      defineSymbol(conf.symbols, "nimdoc")
+      commandJson(cache, conf)
   of "jsondoc2", "jsondoc":
-    conf.cmd = cmdDoc
-    loadConfigs(DocConfig, cache, conf)
-    wantMainModule(conf)
-    defineSymbol(conf.symbols, "nimdoc")
-    commandDoc2(graph, true)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      conf.cmd = cmdDoc
+      loadConfigs(DocConfig, cache, conf)
+      wantMainModule(conf)
+      defineSymbol(conf.symbols, "nimdoc")
+      commandDoc2(graph, true)
   of "ctags":
-    wantMainModule(conf)
-    conf.cmd = cmdDoc
-    loadConfigs(DocConfig, cache, conf)
-    defineSymbol(conf.symbols, "nimdoc")
-    commandTags(cache, conf)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      wantMainModule(conf)
+      conf.cmd = cmdDoc
+      loadConfigs(DocConfig, cache, conf)
+      defineSymbol(conf.symbols, "nimdoc")
+      commandTags(cache, conf)
   of "buildindex":
-    conf.cmd = cmdDoc
-    loadConfigs(DocConfig, cache, conf)
-    commandBuildIndex(cache, conf)
+    when defined(leanCompiler):
+      quit "compiler wasn't built with documentation generator"
+    else:
+      conf.cmd = cmdDoc
+      loadConfigs(DocConfig, cache, conf)
+      commandBuildIndex(cache, conf)
   of "gendepend":
     conf.cmd = cmdGenDepend
     commandGenDepend(graph)