Introduce needsCodegen.

This is a backport of the code from 2.065.

dmd2/declaration.h

@@ -921,6 +921,9 @@ public:
     void toObjFile(int multiobj);                       // compile to .obj file
     int cvMember(unsigned char *p);
     void buildClosure(IRState *irs); // Should this be inside or outside the #if IN_DMD?
+#endif
+#if IN_LLVM // backported from 2.065
+    bool needsCodegen();
 #endif
     FuncDeclaration *isFuncDeclaration() { return this; }
 

dmd2/dsymbol.c

@@ -821,6 +821,35 @@ void Dsymbol::addComment(utf8_t *comment)
 #endif
 }
 
+#if IN_LLVM // backported from 2.065
+/****************************************
+ * Returns true if this symbol is defined in non-root module.
+ */
+
+bool Dsymbol::inNonRoot()
+{
+    Dsymbol *s = parent;
+    for (; s; s = s->parent)
+    {
+        if (TemplateInstance *ti = s->isTemplateInstance())
+        {
+            if (ti->isTemplateMixin())
+                continue;
+            if (!ti->instantiatingModule || !ti->instantiatingModule->isRoot())
+                return true;
+            return false;
+        }
+        else if (Module *m = s->isModule())
+        {
+            if (!m->isRoot())
+                return true;
+            break;
+        }
+    }
+    return false;
+}
+#endif
+
 /********************************* OverloadSet ****************************/
 
 #if DMDV2

dmd2/dsymbol.h

@@ -231,6 +231,9 @@ public:
     virtual void checkCtorConstInit() { }
 
     virtual void addComment(utf8_t *comment);
+#if IN_LLVM // backported from 2.065
+    bool inNonRoot();
+#endif
     virtual void emitComment(Scope *sc);
     void emitDitto(Scope *sc);
 

dmd2/func.c

@@ -3965,6 +3965,93 @@ bool FuncDeclaration::hasNestedFrameRefs()
     return false;
 }
 
+#if IN_LLVM // backported from 2.065
+/***********************************************
+ * Returns true if this function is not defined in non-root module, nor
+ * obviously instantiated in non-root module.
+ *
+ * Note: ti->instantiatingModule does not stabilize until semantic analysis is completed,
+ * so don't call this function during semantic analysis to return precise result.
+ */
+
+bool FuncDeclaration::needsCodegen()
+{
+    assert(semanticRun == PASSsemantic3done);
+
+    for (FuncDeclaration *fd = this; fd; )
+    {
+        if (!fd->inTemplateInstance() && fd->inNonRoot())
+            return false;
+        if (fd->isNested())
+            fd = fd->toParent2()->isFuncDeclaration();
+        else
+            break;
+    }
+
+    /* The issue is that if the importee is compiled with a different -debug
+     * setting than the importer, the importer may believe it exists
+     * in the compiled importee when it does not, when the instantiation
+     * is behind a conditional debug declaration.
+     */
+    // workaround for Bugzilla 11239
+    if (global.params.useUnitTests ||
+        global.params.allInst ||
+        global.params.debuglevel)
+    {
+        return true;
+    }
+
+    FuncDeclaration *fd = this;
+Lagain:
+    TemplateInstance *ti = fd->inTemplateInstance();
+    if (ti && ti->instantiatingModule && !ti->instantiatingModule->isRoot())
+    {
+        Module *mi = ti->instantiatingModule;
+
+        // If mi imports any root modules, we still need to generate the code.
+        for (size_t i = 0; i < Module::amodules.dim; ++i)
+        {
+            Module *m = Module::amodules[i];
+            m->insearch = 0;
+        }
+        bool importsRoot = false;
+        for (size_t i = 0; i < Module::amodules.dim; ++i)
+        {
+            Module *m = Module::amodules[i];
+            if (m->isRoot() && mi->imports(m))
+            {
+                importsRoot = true;
+                break;
+            }
+        }
+        for (size_t i = 0; i < Module::amodules.dim; ++i)
+        {
+            Module *m = Module::amodules[i];
+            m->insearch = 0;
+        }
+        if (!importsRoot)
+        {
+            //printf("instantiated by %s   %s\n", ti->instantiatingModule->toChars(), ti->toChars());
+            return false;
+        }
+    }
+
+    if (fd->isNested())
+    {
+        /* Bugzilla 11863: The enclosing function must have its code generated first.
+         * Therefore if parent is instantiated in non-root, this function also prevent
+         * code generation.
+         */
+        fd = fd->toParent2()->isFuncDeclaration();
+        if (fd)
+            goto Lagain;
+    }
+    //if (AggregateDeclaration *ad = fd->isMember2()) { ... }
+
+    return true;
+}
+#endif
+
 /*********************************************
  * Return the function's parameter list, and whether
  * it is variadic or not.

driver/main.cpp

@@ -801,6 +801,7 @@ static void dumpPredefinedVersions()
 }
 
 static Module *entrypoint = NULL;
+static Module *rootHasMain = NULL;
 
 /// Callback to generate a C main() function, invoked by the frontend.
 void genCmain(Scope *sc)
@@ -830,7 +831,7 @@ void genCmain(Scope *sc)
 
     char v = global.params.verbose;
     global.params.verbose = 0;
-    m->importedFrom = sc->module;
+    m->importedFrom = m;
     m->importAll(NULL);
     m->semantic();
     m->semantic2();
@@ -838,6 +839,7 @@ void genCmain(Scope *sc)
     global.params.verbose = v;
 
     entrypoint = m;
+    rootHasMain = sc->module;
 }
 
 int main(int argc, char **argv)
@@ -1252,7 +1254,7 @@ int main(int argc, char **argv)
         if (global.params.obj)
         {
             llvm::Module* lm = m->genLLVMModule(context);
-            if (entrypoint && entrypoint->importedFrom == m)
+            if (entrypoint && rootHasMain == m)
             {
 #if LDC_LLVM_VER >= 303
                 llvm::Linker linker(lm);

gen/functions.cpp

@@ -928,44 +928,44 @@ void DtoDefineFunction(FuncDeclaration* fd)
 
     if (fd->ir.defined) return;
 
-    // Skip generating code for this part of a TemplateInstance if it has been
-    // instantiated by any non-root module (i.e. a module not listed on the
-    // command line).
-    // See DMD's FuncDeclaration::toObjFile. Check this before calling
-    // DtoDeclareFunction DtoDeclareFunction to avoid touching unanalyzed code.
-    TemplateInstance *ti = fd->inTemplateInstance();
-    if (!global.params.useUnitTests &&
-        ti && ti->instantiatingModule && !ti->instantiatingModule->isRoot())
+    if ((fd->type && fd->type->ty == Tfunction && static_cast<TypeFunction *>(fd->type)->next == NULL) ||
+        (fd->type && fd->type->ty == Tfunction && static_cast<TypeFunction *>(fd->type)->next->ty == Terror))
     {
-        Module *mi = ti->instantiatingModule;
-
-        // If mi imports any root modules, we still need to generate the code.
-        for (size_t i = 0; i < Module::amodules.dim; ++i)
-        {
-            Module *m = Module::amodules[i];
-            m->insearch = 0;
-        }
-        bool importsRoot = false;
-        for (size_t i = 0; i < Module::amodules.dim; ++i)
-        {
-            Module *m = Module::amodules[i];
-            if (m->isRoot() && mi->imports(m))
-            {
-                importsRoot = true;
-                break;
-            }
-        }
-        for (size_t i = 0; i < Module::amodules.dim; ++i)
-        {
-            Module *m = Module::amodules[i];
-            m->insearch = 0;
-        }
-        if (!importsRoot)
-        {
-            IF_LOG Logger::println("Ignoring; already instantiated in %s (%s)", ti->instantiatingModule->toChars(), ti->toChars());
+        IF_LOG Logger::println("Ignoring; no return type or return error type");
         fd->ir.defined = true;
         return;
     }
+
+    if (fd->isUnitTestDeclaration() && !global.params.useUnitTests)
+    {
+        IF_LOG Logger::println("No code generation for unit test declaration %s", fd->toChars());
+        fd->ir.defined = true;
+        return;
+    }
+
+    if (fd->semanticRun == PASSsemanticdone)
+    {
+        /* What happened is this function failed semantic3() with errors,
+         * but the errors were gagged.
+         * Try to reproduce those errors, and then fail.
+         */
+        error("errors compiling function %s", fd->toPrettyChars());
+        fd->ir.defined = true;
+        return;
+    }
+    assert(fd->semanticRun == PASSsemantic3done);
+    assert(fd->ident != Id::empty);
+
+    // Skip generating code for this part of a TemplateInstance if it has been
+    // instantiated by any non-root module (i.e. a module not listed on the
+    // command line).
+    // Check this before calling DtoDeclareFunction to avoid touching
+    // unanalyzed code.
+    if (!fd->needsCodegen())
+    {
+        IF_LOG Logger::println("No code generation for %s", fd->toChars());
+        fd->ir.defined = true;
+        return;
     }
 
     DtoDeclareFunction(fd);

gen/toir.cpp

@@ -2839,6 +2839,13 @@ DValue* FuncExp::toElem(IRState* p)
     // We need to actually codegen the function here, as literals are not added
     // to the module member list.
     fd->codegen(p);
+    if (!fd->ir.irFunc)
+    {
+        // See DtoDefineFunction for reasons why codegen was suppressed.
+        // Instead just declare the function.
+        DtoDeclareFunction(fd);
+        assert(!fd->isNested());
+    }
     assert(fd->ir.irFunc->func);
 
     if (fd->isNested()) {