[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Piotr Padlewski via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Prazek marked an inline comment as done.
Closed by commit rC334600: Add -fforce-emit-vtables (authored by Prazek, 
committed by ).

Changed prior to commit:
  https://reviews.llvm.org/D47108?vs=150735=151154#toc

Repository:
  rC Clang

https://reviews.llvm.org/D47108

Files:
  docs/ClangCommandLineReference.rst
  docs/ReleaseNotes.rst
  docs/UsersManual.rst
  include/clang/Basic/LangOptions.def
  include/clang/Driver/Options.td
  include/clang/Frontend/CodeGenOptions.def
  lib/CodeGen/ItaniumCXXABI.cpp
  lib/Driver/ToolChains/Clang.cpp
  lib/Frontend/CompilerInvocation.cpp
  lib/Sema/SemaDeclCXX.cpp
  test/CodeGenCXX/vtable-available-externally.cpp

Index: docs/ClangCommandLineReference.rst
===
--- docs/ClangCommandLineReference.rst
+++ docs/ClangCommandLineReference.rst
@@ -1934,6 +1934,12 @@
 
 Enables whole-program vtable optimization. Requires -flto
 
+.. option:: -fforce-emit-vtables, -fno-force-emit-vtables
+
+In order to improve devirtualization, forces emitting of vtables even in
+modules where it isn't necessary. It causes more inline virtual functions
+to be emitted.
+
 .. option:: -fwrapv, -fno-wrapv
 
 Treat signed integer overflow as two's complement
Index: docs/UsersManual.rst
===
--- docs/UsersManual.rst
+++ docs/UsersManual.rst
@@ -1269,6 +1269,12 @@
devirtualization and virtual constant propagation, for classes with
:doc:`hidden LTO visibility `. Requires ``-flto``.
 
+.. option:: -fforce-emit-vtables
+
+   In order to improve devirtualization, forces emitting of vtables even in
+   modules where it isn't necessary. It causes more inline virtual functions
+   to be emitted.
+
 .. option:: -fno-assume-sane-operator-new
 
Don't assume that the C++'s new operator is sane.
Index: docs/ReleaseNotes.rst
===
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -112,6 +112,12 @@
   'no-strict' option, Clang attempts to match the overflowing behavior of the
   target's native float-to-int conversion instructions.
 
+- :option: `-fforce-emit-vtables` and `-fno-force-emit-vtables`.
+
+   In order to improve devirtualization, forces emitting of vtables even in
+   modules where it isn't necessary. It causes more inline virtual functions
+   to be emitted.
+
 - ...
 
 Deprecated Compiler Flags
Index: include/clang/Basic/LangOptions.def
===
--- include/clang/Basic/LangOptions.def
+++ include/clang/Basic/LangOptions.def
@@ -293,6 +293,8 @@
 "controls whether to always emit intrinsic calls to "
 "__xray_typedevent(...) builtin.")
 
+LANGOPT(ForceEmitVTables, 1, 0, "whether to emit all vtables")
+
 BENIGN_LANGOPT(AllowEditorPlaceholders, 1, 0,
"allow editor placeholders in source")
 
Index: include/clang/Frontend/CodeGenOptions.def
===
--- include/clang/Frontend/CodeGenOptions.def
+++ include/clang/Frontend/CodeGenOptions.def
@@ -332,6 +332,10 @@
 /// Whether to embed source in DWARF debug line section.
 CODEGENOPT(EmbedSource, 1, 0)
 
+/// Whether to emit all vtables
+CODEGENOPT(ForceEmitVTables, 1, 0)
+
+
 #undef CODEGENOPT
 #undef ENUM_CODEGENOPT
 #undef VALUE_CODEGENOPT
Index: include/clang/Driver/Options.td
===
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -1688,6 +1688,11 @@
   HelpText<"Enables whole-program vtable optimization. Requires -flto">;
 def fno_whole_program_vtables : Flag<["-"], "fno-whole-program-vtables">, Group,
   Flags<[CoreOption]>;
+def fforce_emit_vtables : Flag<["-"], "fforce-emit-vtables">, Group,
+Flags<[CC1Option]>,
+HelpText<"Emits more virtual tables to improve devirtualization">;
+def fno_force_emit_vtables : Flag<["-"], "fno-force-emit-vtables">, Group,
+  Flags<[CoreOption]>;
 def fwrapv : Flag<["-"], "fwrapv">, Group, Flags<[CC1Option]>,
   HelpText<"Treat signed integer overflow as two's complement">;
 def fwritable_strings : Flag<["-"], "fwritable-strings">, Group, Flags<[CC1Option]>,
Index: test/CodeGenCXX/vtable-available-externally.cpp
===
--- test/CodeGenCXX/vtable-available-externally.cpp
+++ test/CodeGenCXX/vtable-available-externally.cpp
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -emit-llvm -o %t
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.opt
+// RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.vtable -fforce-emit-vtables -fstrict-vtable-pointers -mconstructor-aliases
 // RUN: FileCheck 

[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith accepted this revision.
rsmith added a comment.

LGTM with one change.




Comment at: clang/include/clang/Basic/LangOptions.def:292
 
+BENIGN_LANGOPT(ForceEmitVTables, 1, 0,
+   "whether to emit all vtables")

I don't think this is benign or even compatible: if we compile a PCH with this 
turned off, and then try to emit code using that PCH, we can miscompile due to 
having not marked the contents of a vtable as used. Please change this from 
`BENIGN_LANGOPT` to just `LANGOPT`.


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Piotr Padlewski via Phabricator via cfe-commits]

Prazek updated this revision to Diff 150735.
Prazek added a comment.

- Fixed templates


Repository:
  rL LLVM

https://reviews.llvm.org/D47108

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/docs/UsersManual.rst
  clang/include/clang/Basic/LangOptions.def
  clang/include/clang/Driver/Options.td
  clang/include/clang/Frontend/CodeGenOptions.def
  clang/lib/CodeGen/ItaniumCXXABI.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/CodeGenCXX/vtable-available-externally.cpp

Index: clang/test/CodeGenCXX/vtable-available-externally.cpp
===
--- clang/test/CodeGenCXX/vtable-available-externally.cpp
+++ clang/test/CodeGenCXX/vtable-available-externally.cpp
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -emit-llvm -o %t
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.opt
+// RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.vtable -fforce-emit-vtables -fstrict-vtable-pointers -mconstructor-aliases
 // RUN: FileCheck --check-prefix=CHECK-TEST1 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST2 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST5 %s < %t
@@ -13,10 +14,13 @@
 // RUN: FileCheck --check-prefix=CHECK-TEST15 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST16 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST17 %s < %t.opt
+// RUN: FileCheck --check-prefix=CHECK-FORCE-EMIT %s < %t.vtable
+
 
 #include 
 
 // CHECK-TEST1: @_ZTVN5Test11AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN5Test11AE = available_externally unnamed_addr constant
 namespace Test1 {
 
 struct A {
@@ -213,14 +217,16 @@
 
 // because A's key function is defined here, vtable is generated in this TU
 // CHECK-TEST10-DAG: @_ZTVN6Test101AE = unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101AE = unnamed_addr constant
 struct A {
   virtual void foo();
   virtual void bar();
 };
 void A::foo() {}
 
 // Because key function is inline we will generate vtable as linkonce_odr.
 // CHECK-TEST10-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
 struct D : A {
   void bar();
 };
@@ -237,14 +243,17 @@
 // can't guarantee that we will be able to refer to bar from name
 // so (at the moment) we can't emit vtable available_externally.
 // CHECK-TEST10-DAG: @_ZTVN6Test101CE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101CE = available_externally unnamed_addr constant
 struct C : A {
   void bar() {}   // defined in body - not key function
   virtual inline void gar();  // inline in body - not key function
   virtual void car();
 };
 
 // no key function, vtable will be generated everywhere it will be used
 // CHECK-TEST10-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+
 struct E : A {};
 
 void g(A& a) {
@@ -298,11 +307,13 @@
 namespace Test12 {
 
 // CHECK-TEST12: @_ZTVN6Test121AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121AE = available_externally unnamed_addr constant
 struct A {
   virtual void foo();
   virtual ~A() {}
 };
 // CHECK-TEST12: @_ZTVN6Test121BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121BE = available_externally unnamed_addr constant
 struct B : A {
   void foo();
 };
@@ -319,6 +330,9 @@
 
 // CHECK-TEST13-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
 // CHECK-TEST13-DAG: @_ZTVN6Test131BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131BE = available_externally unnamed_addr constant
+
 struct A {
   virtual ~A();
 };
@@ -371,6 +385,8 @@
 // generate available_externally vtable for it.
 // CHECK-TEST16-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
 // CHECK-TEST16-DAG: @_ZTVN6Test162S2E = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test162S2E = available_externally
 
 struct S {
   __attribute__((visibility("hidden"))) virtual void doStuff();
@@ -395,6 +411,10 @@
 // This test checks if we emit vtables opportunistically.
 // CHECK-TEST17-DAG: @_ZTVN6Test171AE = available_externally
 // CHECK-TEST17-DAG: @_ZTVN6Test171BE = external
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171AE = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171BE = available_externally
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD2Ev(
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD0Ev(
 
 struct A {
   virtual void key();
@@ -418,3 

[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith accepted this revision.
rsmith added a comment.

I would like to see a test that virtual function definitions are properly 
emitted for classes instantiated from templates (and in particular, that this 
triggers instantiation of such virtual member functions so they can be 
emitted). Other than that, this looks good to me.


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Krzysztof Pszeniczny via Phabricator via cfe-commits]

amharc accepted this revision.
amharc added a comment.
This revision is now accepted and ready to land.

Looks good to me. Obviously, you should wait for someone more competent than me 
to accept it, too.


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Piotr Padlewski via Phabricator via cfe-commits]

Prazek updated this revision to Diff 148839.
Prazek marked an inline comment as done.
Prazek added a comment.

fixed test


Repository:
  rL LLVM

https://reviews.llvm.org/D47108

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/docs/UsersManual.rst
  clang/include/clang/Basic/LangOptions.def
  clang/include/clang/Driver/Options.td
  clang/include/clang/Frontend/CodeGenOptions.def
  clang/lib/CodeGen/ItaniumCXXABI.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/CodeGenCXX/vtable-available-externally.cpp

Index: clang/test/CodeGenCXX/vtable-available-externally.cpp
===
--- clang/test/CodeGenCXX/vtable-available-externally.cpp
+++ clang/test/CodeGenCXX/vtable-available-externally.cpp
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -emit-llvm -o %t
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.opt
+// RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.vtable -fforce-emit-vtables -fstrict-vtable-pointers -mconstructor-aliases
 // RUN: FileCheck --check-prefix=CHECK-TEST1 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST2 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST5 %s < %t
@@ -13,10 +14,13 @@
 // RUN: FileCheck --check-prefix=CHECK-TEST15 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST16 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST17 %s < %t.opt
+// RUN: FileCheck --check-prefix=CHECK-FORCE-EMIT %s < %t.vtable
+
 
 #include 
 
 // CHECK-TEST1: @_ZTVN5Test11AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN5Test11AE = available_externally unnamed_addr constant
 namespace Test1 {
 
 struct A {
@@ -213,14 +217,16 @@
 
 // because A's key function is defined here, vtable is generated in this TU
 // CHECK-TEST10-DAG: @_ZTVN6Test101AE = unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101AE = unnamed_addr constant
 struct A {
   virtual void foo();
   virtual void bar();
 };
 void A::foo() {}
 
 // Because key function is inline we will generate vtable as linkonce_odr.
 // CHECK-TEST10-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
 struct D : A {
   void bar();
 };
@@ -237,14 +243,17 @@
 // can't guarantee that we will be able to refer to bar from name
 // so (at the moment) we can't emit vtable available_externally.
 // CHECK-TEST10-DAG: @_ZTVN6Test101CE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101CE = available_externally unnamed_addr constant
 struct C : A {
   void bar() {}   // defined in body - not key function
   virtual inline void gar();  // inline in body - not key function
   virtual void car();
 };
 
 // no key function, vtable will be generated everywhere it will be used
 // CHECK-TEST10-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+
 struct E : A {};
 
 void g(A& a) {
@@ -298,11 +307,13 @@
 namespace Test12 {
 
 // CHECK-TEST12: @_ZTVN6Test121AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121AE = available_externally unnamed_addr constant
 struct A {
   virtual void foo();
   virtual ~A() {}
 };
 // CHECK-TEST12: @_ZTVN6Test121BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121BE = available_externally unnamed_addr constant
 struct B : A {
   void foo();
 };
@@ -319,6 +330,9 @@
 
 // CHECK-TEST13-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
 // CHECK-TEST13-DAG: @_ZTVN6Test131BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131BE = available_externally unnamed_addr constant
+
 struct A {
   virtual ~A();
 };
@@ -371,6 +385,8 @@
 // generate available_externally vtable for it.
 // CHECK-TEST16-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
 // CHECK-TEST16-DAG: @_ZTVN6Test162S2E = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test162S2E = available_externally
 
 struct S {
   __attribute__((visibility("hidden"))) virtual void doStuff();
@@ -395,6 +411,10 @@
 // This test checks if we emit vtables opportunistically.
 // CHECK-TEST17-DAG: @_ZTVN6Test171AE = available_externally
 // CHECK-TEST17-DAG: @_ZTVN6Test171BE = external
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171AE = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171BE = available_externally
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD2Ev(
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD0Ev(
 
 struct A {
  

[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Krzysztof Pszeniczny via Phabricator via cfe-commits]

amharc requested changes to this revision.
amharc added inline comments.
This revision now requires changes to proceed.



Comment at: clang/test/CodeGenCXX/vtable-available-externally.cpp:445
+// after the Derived construction.
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test187DerivedE = linkonce_odr unnamed_addr 
constant {{.*}} @_ZTIN6Test187DerivedE {{.*}} @_ZN6Test184Base3funEv {{.*}} 
@_ZN6Test187DerivedD1Ev {{.*}} @_ZN6Test187DerivedD0Ev
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test187DerivedD0Ev

This still uses `_ZN6Test187DerivedD1Ev` instead of `_ZN6Test184BaseD2Ev`, 
because the triple you selected is `x86_64-apple-darwin10` and 
`-mconstructor-aliases` is off by default on Darwin.

I suggest you either add `-mconstructor-aliases` to the compiler invocation or 
change the triple to literally everything else than Darwin (or CUDA). 
Preferably the former, as it shows clearly what we want to test here.


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Piotr Padlewski via Phabricator via cfe-commits]

Prazek updated this revision to Diff 148764.
Prazek added a comment.

small update


Repository:
  rL LLVM

https://reviews.llvm.org/D47108

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/docs/UsersManual.rst
  clang/include/clang/Basic/LangOptions.def
  clang/include/clang/Driver/Options.td
  clang/include/clang/Frontend/CodeGenOptions.def
  clang/lib/CodeGen/ItaniumCXXABI.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/CodeGenCXX/vtable-available-externally.cpp

Index: clang/test/CodeGenCXX/vtable-available-externally.cpp
===
--- clang/test/CodeGenCXX/vtable-available-externally.cpp
+++ clang/test/CodeGenCXX/vtable-available-externally.cpp
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -emit-llvm -o %t
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.opt
+// RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.vtable -fforce-emit-vtables -fstrict-vtable-pointers
 // RUN: FileCheck --check-prefix=CHECK-TEST1 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST2 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST5 %s < %t
@@ -13,10 +14,13 @@
 // RUN: FileCheck --check-prefix=CHECK-TEST15 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST16 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST17 %s < %t.opt
+// RUN: FileCheck --check-prefix=CHECK-FORCE-EMIT %s < %t.vtable
+
 
 #include 
 
 // CHECK-TEST1: @_ZTVN5Test11AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN5Test11AE = available_externally unnamed_addr constant
 namespace Test1 {
 
 struct A {
@@ -213,14 +217,16 @@
 
 // because A's key function is defined here, vtable is generated in this TU
 // CHECK-TEST10-DAG: @_ZTVN6Test101AE = unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101AE = unnamed_addr constant
 struct A {
   virtual void foo();
   virtual void bar();
 };
 void A::foo() {}
 
 // Because key function is inline we will generate vtable as linkonce_odr.
 // CHECK-TEST10-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
 struct D : A {
   void bar();
 };
@@ -237,14 +243,17 @@
 // can't guarantee that we will be able to refer to bar from name
 // so (at the moment) we can't emit vtable available_externally.
 // CHECK-TEST10-DAG: @_ZTVN6Test101CE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101CE = available_externally unnamed_addr constant
 struct C : A {
   void bar() {}   // defined in body - not key function
   virtual inline void gar();  // inline in body - not key function
   virtual void car();
 };
 
 // no key function, vtable will be generated everywhere it will be used
 // CHECK-TEST10-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+
 struct E : A {};
 
 void g(A& a) {
@@ -298,11 +307,13 @@
 namespace Test12 {
 
 // CHECK-TEST12: @_ZTVN6Test121AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121AE = available_externally unnamed_addr constant
 struct A {
   virtual void foo();
   virtual ~A() {}
 };
 // CHECK-TEST12: @_ZTVN6Test121BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121BE = available_externally unnamed_addr constant
 struct B : A {
   void foo();
 };
@@ -319,6 +330,9 @@
 
 // CHECK-TEST13-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
 // CHECK-TEST13-DAG: @_ZTVN6Test131BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131BE = available_externally unnamed_addr constant
+
 struct A {
   virtual ~A();
 };
@@ -371,6 +385,8 @@
 // generate available_externally vtable for it.
 // CHECK-TEST16-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
 // CHECK-TEST16-DAG: @_ZTVN6Test162S2E = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test162S2E = available_externally
 
 struct S {
   __attribute__((visibility("hidden"))) virtual void doStuff();
@@ -395,6 +411,10 @@
 // This test checks if we emit vtables opportunistically.
 // CHECK-TEST17-DAG: @_ZTVN6Test171AE = available_externally
 // CHECK-TEST17-DAG: @_ZTVN6Test171BE = external
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171AE = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171BE = available_externally
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD1Ev(
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD0Ev(
 
 struct A {
   virtual void key();
@@ -418,3 +438,27 @@
 }
 
 } // 

[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Piotr Padlewski via Phabricator via cfe-commits]

Prazek updated this revision to Diff 148762.
Prazek added a comment.

Fixed missing vtable commponents


Repository:
  rL LLVM

https://reviews.llvm.org/D47108

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/docs/UsersManual.rst
  clang/include/clang/Basic/LangOptions.def
  clang/include/clang/Driver/Options.td
  clang/include/clang/Frontend/CodeGenOptions.def
  clang/lib/CodeGen/ItaniumCXXABI.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/CodeGenCXX/vtable-available-externally.cpp

Index: clang/test/CodeGenCXX/vtable-available-externally.cpp
===
--- clang/test/CodeGenCXX/vtable-available-externally.cpp
+++ clang/test/CodeGenCXX/vtable-available-externally.cpp
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -emit-llvm -o %t
 // RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.opt
+// RUN: %clang_cc1 %s -I%S -triple=x86_64-apple-darwin10 -std=c++98 -O2 -disable-llvm-passes -emit-llvm -o %t.vtable -fforce-emit-vtables -fstrict-vtable-pointers
 // RUN: FileCheck --check-prefix=CHECK-TEST1 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST2 %s < %t
 // RUN: FileCheck --check-prefix=CHECK-TEST5 %s < %t
@@ -13,10 +14,13 @@
 // RUN: FileCheck --check-prefix=CHECK-TEST15 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST16 %s < %t.opt
 // RUN: FileCheck --check-prefix=CHECK-TEST17 %s < %t.opt
+// RUN: FileCheck --check-prefix=CHECK-FORCE-EMIT %s < %t.vtable
+
 
 #include 
 
 // CHECK-TEST1: @_ZTVN5Test11AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN5Test11AE = available_externally unnamed_addr constant
 namespace Test1 {
 
 struct A {
@@ -213,14 +217,16 @@
 
 // because A's key function is defined here, vtable is generated in this TU
 // CHECK-TEST10-DAG: @_ZTVN6Test101AE = unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101AE = unnamed_addr constant
 struct A {
   virtual void foo();
   virtual void bar();
 };
 void A::foo() {}
 
 // Because key function is inline we will generate vtable as linkonce_odr.
 // CHECK-TEST10-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
 struct D : A {
   void bar();
 };
@@ -237,14 +243,17 @@
 // can't guarantee that we will be able to refer to bar from name
 // so (at the moment) we can't emit vtable available_externally.
 // CHECK-TEST10-DAG: @_ZTVN6Test101CE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101CE = available_externally unnamed_addr constant
 struct C : A {
   void bar() {}   // defined in body - not key function
   virtual inline void gar();  // inline in body - not key function
   virtual void car();
 };
 
 // no key function, vtable will be generated everywhere it will be used
 // CHECK-TEST10-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test101EE = linkonce_odr unnamed_addr constant
+
 struct E : A {};
 
 void g(A& a) {
@@ -298,11 +307,13 @@
 namespace Test12 {
 
 // CHECK-TEST12: @_ZTVN6Test121AE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121AE = available_externally unnamed_addr constant
 struct A {
   virtual void foo();
   virtual ~A() {}
 };
 // CHECK-TEST12: @_ZTVN6Test121BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test121BE = available_externally unnamed_addr constant
 struct B : A {
   void foo();
 };
@@ -319,6 +330,9 @@
 
 // CHECK-TEST13-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
 // CHECK-TEST13-DAG: @_ZTVN6Test131BE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131AE = available_externally unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test131BE = available_externally unnamed_addr constant
+
 struct A {
   virtual ~A();
 };
@@ -371,6 +385,8 @@
 // generate available_externally vtable for it.
 // CHECK-TEST16-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
 // CHECK-TEST16-DAG: @_ZTVN6Test162S2E = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test161SE = external unnamed_addr constant
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test162S2E = available_externally
 
 struct S {
   __attribute__((visibility("hidden"))) virtual void doStuff();
@@ -395,6 +411,10 @@
 // This test checks if we emit vtables opportunistically.
 // CHECK-TEST17-DAG: @_ZTVN6Test171AE = available_externally
 // CHECK-TEST17-DAG: @_ZTVN6Test171BE = external
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171AE = available_externally
+// CHECK-FORCE-EMIT-DAG: @_ZTVN6Test171BE = available_externally
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD1Ev(
+// CHECK-FORCE-EMIT-DAG: define linkonce_odr void @_ZN6Test171BD0Ev(
 
 struct A {
   virtual void key();
@@ -418,3 +438,27 

[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[John McCall via Phabricator via cfe-commits]

rjmccall added a comment.

In https://reviews.llvm.org/D47108#1109145, @Prazek wrote:

> In https://reviews.llvm.org/D47108#1109014, @rjmccall wrote:
>
> > I thought we already had places in Sema that marked inline virtual methods 
> > as used, instantiated templates, etc. for devirtualization purposes when 
> > optimization was enabled.  Did we rip that out?
>
>
> I only recall the emitting available_externally vtables opportunistically, 
> that is emitting it only if all the inline virtual functions are present (and 
> they are not hidden).
>  (https://reviews.llvm.org/D33437)
>
> > The problem we've had over and over with devirtualization is that we have 
> > to emit a perfect v-table because LLVM lacks a lot of the key vocabulary 
> > for talking about incomplete information.  For example, if something weird 
> > happens and we don't have a definition for an inline virtual method, 
> > ideally we'd just say "well, you can't devirtualize this slot", then try to 
> > fix that as incremental progress; but instead we have to get everything 
> > just right or else disable the whole optimization.  Note that vague-linkage 
> > v-tables mean that we'd also need to be able to say things like "there is 
> > an object with a definition that looks like this, but its symbol is not 
> > available and you can't emit it yourself".
>
> That is correcty, my intention was that this flag would cause all inline 
> virtual functions to be emitted. Can you give a hint how to achieve this in 
> the sane way?


Well, this paragraph was really a call for extending LLVM IR, which might be 
outside a reasonable scope for your summer project.

Building a v-table should itself cause inline functions to be emitted in IRGen 
as long as they've been properly marked for instantiation and use by Sema.  I 
don't know the right place to ensure that that happens.


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Piotr Padlewski via Phabricator via cfe-commits]

Prazek added a comment.

In https://reviews.llvm.org/D47108#1109014, @rjmccall wrote:

> I thought we already had places in Sema that marked inline virtual methods as 
> used, instantiated templates, etc. for devirtualization purposes when 
> optimization was enabled.  Did we rip that out?


I only recall the emitting available_externally vtables opportunistically, that 
is emitting it only if all the inline virtual functions are present (and they 
are not hidden).
(https://reviews.llvm.org/D33437)

> The problem we've had over and over with devirtualization is that we have to 
> emit a perfect v-table because LLVM lacks a lot of the key vocabulary for 
> talking about incomplete information.  For example, if something weird 
> happens and we don't have a definition for an inline virtual method, ideally 
> we'd just say "well, you can't devirtualize this slot", then try to fix that 
> as incremental progress; but instead we have to get everything just right or 
> else disable the whole optimization.  Note that vague-linkage v-tables mean 
> that we'd also need to be able to say things like "there is an object with a 
> definition that looks like this, but its symbol is not available and you 
> can't emit it yourself".

That is correcty, my intention was that this flag would cause all inline 
virtual functions to be emitted. Can you give a hint how to achieve this in the 
sane way?


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[John McCall via Phabricator via cfe-commits]

rjmccall added a comment.

I thought we already had places in Sema that marked inline virtual methods as 
used, instantiated templates, etc. for devirtualization purposes when 
optimization was enabled.  Did we rip that out?

The problem we've had over and over with devirtualization is that we have to 
emit a perfect v-table because LLVM lacks a lot of the key vocabulary for 
talking about incomplete information.  For example, if something weird happens 
and we don't have a definition for an inline virtual method, ideally we'd just 
say "well, you can't devirtualize this slot", then try to fix that as 
incremental progress; but instead we have to get everything just right or else 
disable the whole optimization.  Note that vague-linkage v-tables mean that 
we'd also need to be able to say things like "there is an object with a 
definition that looks like this, but its symbol is not available and you can't 
emit it yourself".


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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[PATCH] D47108: [CodeGenCXX] Add -fforce-emit-vtables

[Piotr Padlewski via Phabricator via cfe-commits]

Prazek added a comment.

@rjmccall do you have any thoughts on the best way to solve it?


Repository:
  rL LLVM

https://reviews.llvm.org/D47108



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