From b1bd6fb2ac03ce6cc43855bef9bd45cf9b8fec1a Mon Sep 17 00:00:00 2001
From: Martin Kinkelin <kinke@users.noreply.github.com>
Date: Wed, 30 Sep 2020 21:26:26 +0200
Subject: [PATCH] Don't enforce (normal) emission for pragma(inline, true)
 function templates, and don't cull lambdas (#3570)

With the new available_externally emission into each referencing CU, the
enforced regular emission from the module members tree shouldn't be
required anymore.

After adapting the codegen/inlining_templates.d lit-test accordingly (no
IR definitions anymore in .ll file, because available_externally doesn't
make it there), I've noticed that a lambda in imported and inlined
call_enforce_with_default_template_params() wasn't emitted - it got
culled by alreadyOrWillBeDefined().
Function/delegate literals aren't culled anymore.
---
 gen/declarations.cpp               | 33 +++++++++++-------------------
 gen/function-inlining.cpp          |  3 +++
 tests/codegen/inlining_templates.d | 10 ++++-----
 3 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/gen/declarations.cpp b/gen/declarations.cpp
index e29a385cbe..e648f109de 100644
--- a/gen/declarations.cpp
+++ b/gen/declarations.cpp
@@ -371,28 +371,19 @@ public:
       return;
     }
 
-    // Force codegen if this is a templated function with pragma(inline, true).
-    if ((decl->members->length == 1) &&
-        ((*decl->members)[0]->isFuncDeclaration()) &&
-        ((*decl->members)[0]->isFuncDeclaration()->inlining == PINLINEalways)) {
-      Logger::println("needsCodegen() == false, but function is marked with "
-                      "pragma(inline, true), so it really does need "
-                      "codegen.");
-    } else {
-      // FIXME: This is #673 all over again.
-      if (!decl->needsCodegen()) {
-        Logger::println("Does not need codegen, skipping.");
-        return;
-      }
+    // FIXME: This is #673 all over again.
+    if (!decl->needsCodegen()) {
+      Logger::println("Does not need codegen, skipping.");
+      return;
+    }
 
-      if (irs->dcomputetarget && (decl->tempdecl == Type::rtinfo ||
-                                  decl->tempdecl == Type::rtinfoImpl)) {
-        // Emitting object.RTInfo(Impl) template instantiations in dcompute
-        // modules would require dcompute support for global variables.
-        Logger::println("Skipping object.RTInfo(Impl) template instantiations "
-                        "in dcompute modules.");
-        return;
-      }
+    if (irs->dcomputetarget && (decl->tempdecl == Type::rtinfo ||
+                                decl->tempdecl == Type::rtinfoImpl)) {
+      // Emitting object.RTInfo(Impl) template instantiations in dcompute
+      // modules would require dcompute support for global variables.
+      Logger::println("Skipping object.RTInfo(Impl) template instantiations "
+                      "in dcompute modules.");
+      return;
     }
 
     for (auto &m : *decl->members) {
diff --git a/gen/function-inlining.cpp b/gen/function-inlining.cpp
index fc84fe1524..8d23f32bca 100644
--- a/gen/function-inlining.cpp
+++ b/gen/function-inlining.cpp
@@ -73,6 +73,9 @@ bool isInlineCandidate(FuncDeclaration &fdecl) {
 } // end anonymous namespace
 
 bool alreadyOrWillBeDefined(FuncDeclaration &fdecl) {
+  if (fdecl.isFuncLiteralDeclaration()) // emitted into each referencing CU
+    return true;
+
   for (FuncDeclaration *f = &fdecl; f;) {
     if (!f->isInstantiated() && f->inNonRoot()) {
       return false;
diff --git a/tests/codegen/inlining_templates.d b/tests/codegen/inlining_templates.d
index 1112e99518..510929d790 100644
--- a/tests/codegen/inlining_templates.d
+++ b/tests/codegen/inlining_templates.d
@@ -31,10 +31,8 @@ void main()
 {
 }
 
-// CHECK-NOT: declare{{.*}}_D6inputs10inlinables__T12template_fooTiZQrUNaNbNiNfiZi
-// CHECK-NOT: declare{{.*}}_D3std9exception__T7enforce
+// CHECK-NOT: declare {{.*}}template_foo
 
-// CHECK-DAG: define{{.*}}_D6inputs10inlinables__T12template_fooTiZQrUNaNbNiNfiZi{{.*}}) #[[ATTR:[0-9]+]]
-// CHECK-DAG: define{{.*}}_D3std9exception__T7enforce{{.*}}) #[[ATTR]]
-
-// CHECK-DAG: attributes #[[ATTR]] ={{.*}} alwaysinline
+// CHECK-NOT: declare {{.*}}call_enforce_with_default_template_params
+// CHECK-NOT: declare {{.*}}__lambda
+// CHECK-NOT: declare {{.*}}_D3std9exception__T7enforce