Implement pragma compile on import bugzilla #24869

changelog/dmd.pragma.compileonimport.dd

@@ -0,0 +1,30 @@
+Add a new pragma to compile on import
+
+The pragma ``compileOnImport``, will convert an imported module into one that will be compiled into your binary.
+
+This is the same behavior as the ``-i`` switch, except it is a pragma in a module.
+
+A library module:
+
+```d
+module mylib;
+pragma(compileOnImport);
+
+void callMe() {
+ import std.stdio;
+ writeln("Hello!");
+}
+```
+
+The user module:
+
+```d
+module theuser;
+import mylib;
+
+void main() {
+ callMe(); // Hello!
+}
+```
+
+Compile with ``dmd -I. theuser.d``

compiler/src/dmd/frontend.h

@@ -8583,6 +8583,7 @@ struct Id final
  static Identifier* startaddress;
  static Identifier* crt_constructor;
  static Identifier* crt_destructor;
+ static Identifier* compileOnImport;
  static Identifier* tohash;
  static Identifier* tostring;
  static Identifier* getmembers;

compiler/src/dmd/id.d

@@ -352,6 +352,7 @@ immutable Msgtable[] msgtable =
  { "startaddress" },
  { "crt_constructor" },
  { "crt_destructor" },
+ { "compileOnImport" },
 
  // For special functions
  { "tohash", "toHash" },

compiler/src/dmd/main.d

@@ -567,20 +567,20 @@ private int tryMain(size_t argc, const(char)** argv, ref Param params)
  message("semantic3 %s", m.toChars());
  m.semantic3(null);
  }
- if (includeImports)
+
+ // Will be empty if no module has pragma(compileOnImport) or -i is passed to compiler.
+ // Note: DO NOT USE foreach here because Module.amodules.length can
+ // change on each iteration of the loop
+ for (size_t i = 0; i < compiledImports.length; i++)
  {
- // Note: DO NOT USE foreach here because Module.amodules.length can
- // change on each iteration of the loop
- for (size_t i = 0; i < compiledImports.length; i++)
- {
- auto m = compiledImports[i];
- assert(m.isRoot);
- if (params.v.verbose)
- message("semantic3 %s", m.toChars());
- m.semantic3(null);
- modules.push(m);
- }
+ auto m = compiledImports[i];
+ assert(m.isRoot);
+ if (params.v.verbose)
+ message("semantic3 %s", m.toChars());
+ m.semantic3(null);
+ modules.push(m);
  }
+
  Module.runDeferredSemantic3();
  if (global.errors)
  removeHdrFilesAndFail(params, modules);

compiler/src/dmd/pragmasem.d

@@ -320,6 +320,18 @@ void pragmaDeclSemantic(PragmaDeclaration pd, Scope* sc)
  .error(pd.loc, "%s `%s` takes no argument", pd.kind, pd.toPrettyChars);
  return declarations();
  }
+ else if (pd.ident == Id.compileOnImport)
+ {
+ import dmd.compiler;
+
+ if (!sc._module.isRoot())
+ {
+ sc._module.importedFrom = sc._module;
+ compiledImports.push(sc._module);
+ }
+
+ return declarations();
+ }
  else if (!global.params.ignoreUnsupportedPragmas)
  {
  error(pd.loc, "unrecognized `pragma(%s)`", pd.ident.toChars());

compiler/test/runnable/compileonimport.d

@@ -0,0 +1,10 @@
+/*
+REQUIRED_ARGS: -Irunnable/imports
+*/
+module compileonimport;
+import compileonimportlib;
+
+void main() {
+ bool v = runMe();
+ assert(v);
+}

compiler/test/runnable/imports/compileonimportlib.d

@@ -0,0 +1,7 @@
+module compileonimportlib;
+
+pragma(compileOnImport);
+
+bool runMe() {
+ return true;
+}