Fix inlining problem: reverse order in which module array is codegenned.

driver/main.cpp

@@ -1393,7 +1393,15 @@ int cppmain(int argc, char **argv) {
   if (global.params.obj && !modules.empty()) {
     ldc::CodeGenerator cg(getGlobalContext(), singleObj);
 
-    for (unsigned i = 0; i < modules.dim; i++) {
+    // When inlining is enabled, we are calling semantic3 on function
+    // declarations, which may _add_ members to the first module in the modules
+    // array. These added functions must be codegenned, because these functions
+    // may be "alwaysinline" and linker problems arise otherwise with templates
+    // that have __FILE__ as parameters (which must be `pragma(inline, true);`)
+    // Therefore, codegen is done in reverse order with members[0] last, to make
+    // sure these functions (added to members[0] by members[x>0]) are
+    // codegenned.
+    for (d_size_t i = modules.dim; i-- > 0;) {
       Module *const m = modules[i];
       if (global.params.verbose) {
         fprintf(global.stdmsg, "code      %s\n", m->toChars());

gen/functions.cpp

@@ -79,49 +79,69 @@ bool defineAsExternallyAvailable(FuncDeclaration &fdecl) {
   IF_LOG Logger::println("Enter defineAsExternallyAvailable");
   LOG_SCOPE
 
-  // Try to do cheap checks first.
+  // Implementation note: try to do cheap checks first.
 
-  if (fdecl.neverInline || fdecl.inlining == PINLINEnever)
+  if (fdecl.neverInline || fdecl.inlining == PINLINEnever) {
+    IF_LOG Logger::println("pragma(inline, false) specified");
     return false;
+  }
 
   // pragma(inline, true) functions will be inlined even at -O0
-  if (!willInline() && (fdecl.inlining != PINLINEalways))
+  if (!willInline() && (fdecl.inlining != PINLINEalways)) {
+    IF_LOG Logger::println("Commandline flags indicate no inlining");
     return false;
+  }
 
-  if (fdecl.isUnitTestDeclaration())
+  if (fdecl.isUnitTestDeclaration()) {
+    IF_LOG Logger::println("isUnitTestDeclaration() == true");
     return false;
-  if (fdecl.isFuncAliasDeclaration())
+  }
+  if (fdecl.isFuncAliasDeclaration()) {
+    IF_LOG Logger::println("isFuncAliasDeclaration() == true");
     return false;
-  if (!fdecl.fbody)
+  }
+  if (!fdecl.fbody) {
+    IF_LOG Logger::println("No function body available for inlining");
     return false;
+  }
 
-  // Disable inlining functions from object.d because of TypeInfo related issue
-  if (fdecl.getModule()->ident == Id::object)
+  // Disable inlining functions from object.d because of TypeInfo related
+  // issue
+  if (fdecl.getModule()->ident == Id::object) {
+    IF_LOG Logger::println("Inlining of object.d functions is disabled");
     return false;
+  }
 
-  if (alreadyOrWillBeDefined(fdecl))
+  if (alreadyOrWillBeDefined(fdecl)) {
+    IF_LOG Logger::println("Function will be defined later.");
     return false;
+  }
 
   // Weak-linkage functions can not be inlined.
-  if (hasWeakUDA(&fdecl))
+  if (hasWeakUDA(&fdecl)) {
+    IF_LOG Logger::println("@weak functions cannot be inlined.");
     return false;
+  }
 
   if (!isInlineCandidate(fdecl))
     return false;
 
   IF_LOG Logger::println("Potential inlining candidate");
 
-  // If semantic analysis is already complete, the function will be codegenned
-  // elsewhere.
-  if (fdecl.semanticRun >= PASSsemantic3)
+  if (fdecl.semanticRun >= PASSsemantic3) {
+    // If semantic analysis has come this far, the function will be defined
+    // elsewhere and should not get the available_externally attribute from
+    // here.
+    IF_LOG Logger::println("Semantic analysis already completed");
     return false;
+  }
 
   {
     IF_LOG Logger::println("Do semantic analysis");
     LOG_SCOPE
 
-    // The inlining is aggressive and may give semantic errors that are forward
-    // referencing errors. Simply avoid those cases for inlining.
+    // The inlining is aggressive and may give semantic errors that are
+    // forward referencing errors. Simply avoid those cases for inlining.
     uint errors = global.startGagging();
     global.gaggedForInlining = true;
 
@@ -144,9 +164,8 @@ bool defineAsExternallyAvailable(FuncDeclaration &fdecl) {
   // For naked functions (inline assembly), we emit the assembly directly as
   // globals in the text section. Emitting them during this inline pass will
   // therefore result in multiple definitions. Solution: don't try to inline
-  // them.
-  // These naked functions don't appear to be inlined anyway, so it is pointless
-  // at this moment to try.
+  // them. These naked functions don't appear to be inlined anyway, so it is
+  // pointless at this moment to try.
   // FuncDeclaration::naked is set by the AsmParser during semantic analysis.
   if (fdecl.naked) {
     IF_LOG Logger::println("Naked asm functions cannot be inlined.");
@@ -912,22 +931,11 @@ void DtoDefineFunction(FuncDeclaration *fd, bool availableExternally) {
   }
 
   if (!availableExternally) {
-    // Check whether the frontend knows that the function is already defined
-    // in some other module (see DMD's FuncDeclaration::toObjFile).
-    for (FuncDeclaration *f = fd; f;) {
-      if (!f->isInstantiated() && f->inNonRoot()) {
+    if (!alreadyOrWillBeDefined(*fd)) {
       IF_LOG Logger::println("Skipping '%s'.", fd->toPrettyChars());
-        // TODO: Emit as available_externally for inlining purposes instead
-        // (see #673).
       fd->ir->setDefined();
       return;
     }
-      if (f->isNested()) {
-        f = f->toParent2()->isFuncDeclaration();
-      } else {
-        break;
-      }
-    }
   }
 
   DtoDeclareFunction(fd);

tests/codegen/inlining_templates.d

@@ -3,9 +3,14 @@
 
 // RUN: %ldc %s -I%S -c -output-ll -release -enable-inlining -O0 -of=%t.O0.ll && FileCheck %s < %t.O0.ll
 
-// Test linking too (separate compilation)
+// RUN: %ldc -singleobj %S/inputs/inlinables.d %s -I%S -c -output-ll -release -enable-inlining -O0 -of=%t.singleobj.O0.ll && FileCheck %s < %t.singleobj.O0.ll
+
+// Test linking too.
+// Separate compilation
 //   RUN: %ldc -c -enable-inlining %S/inputs/inlinables.d -of=%t.inlinables%obj \
 //   RUN: && %ldc -I%S -enable-inlining %t.inlinables%obj %s -of=%t%exe
+// Singleobj compilation
+//   RUN: %ldc -I%S -enable-inlining -singleobj %S/inputs/inlinables.d %s -of=%t2%exe
 
 import inputs.inlinables;
 import std.stdio;
@@ -15,9 +20,6 @@ int foo(int i)
 {
     return call_template_foo(i);
 }
-// CHECK-NOT: declare{{.*}}D6inputs10inlinables20__T12template_fooTiZ12template_fooUNaNbNiNfiZi
-// CHECK: define{{.*}}D6inputs10inlinables20__T12template_fooTiZ12template_fooUNaNbNiNfiZi
-// CHECK-SAME: #[[ATTR1:[0-9]+]]
 
 // stdio.File.flush contains a call to errnoException, which contains __FILE__ as default template parameter.
 // Make sure the symbol is inlined/defined and not declared (which will lead to linker errors if the location
@@ -27,18 +29,15 @@ void ggg(ref File f)
     f.flush();
 }
 
-// CHECK-NOT: declare{{.*}}D3std9exception{{[0-9]+}}__T12errnoEnforce
-// CHECK: define{{.*}}D3std9exception{{[0-9]+}}__T12errnoEnforce
-// CHECK-SAME: #[[ATTR2:[0-9]+]]
-
-void hhh()
-{
-    auto f = File("filename","r");
-}
-
 void main()
 {
 }
 
+// CHECK-NOT: declare{{.*}}D6inputs10inlinables20__T12template_fooTiZ12template_foo
+// CHECK-NOT: declare{{.*}}D3std9exception{{[0-9]+}}__T12errnoEnforce
+
+// CHECK-DAG: define{{.*}}D6inputs10inlinables20__T12template_fooTiZ12template_foo{{.*}}) #[[ATTR1:[0-9]+]]
+// CHECK-DAG: define{{.*}}D3std9exception{{[0-9]+}}__T12errnoEnforce{{.*}}) #[[ATTR2:[0-9]+]]
+
 // CHECK-DAG: attributes #[[ATTR1]] ={{.*}} alwaysinline
 // CHECK-DAG: attributes #[[ATTR2]] ={{.*}} alwaysinline

tests/codegen/inputs/inlinables.d

@@ -102,13 +102,12 @@ pragma(inline, true) extern (C) void naked_asm_func()
     }
 }
 
-pragma(inline, true)
-int call_template_foo(int i) {
+pragma(inline, true) int call_template_foo(int i)
+{
     return template_foo(i);
 }
 
-pragma(inline, true)
-T template_foo(T)(T i)
+pragma(inline, true) T template_foo(T)(T i)
 {
     return i;
 }