Add support for /Ob1 and -finline-hint-functions flags

Add support for /Ob1 (and equivalent -finline-hint-functions), which enable
inlining only for functions marked inline, either explicitly (via inline
keyword, for example), or implicitly (function definition in class body,
for example).

This works by enabling inlining pass, and adding noinline attribute to
every function not marked inline.

Patch by Rudy Pons <rudy.pons@ilod.org>!

Differential Revision: http://reviews.llvm.org/D20647

llvm-svn: 273440

clang/include/clang/Driver/CLCompatOptions.td

@@ -291,7 +291,6 @@ def _SLASH_FS : CLIgnoredFlag<"FS">, HelpText<"Force synchronous PDB writes">;
 def _SLASH_GF : CLIgnoredFlag<"GF">;
 def _SLASH_kernel_ : CLIgnoredFlag<"kernel-">;
 def _SLASH_nologo : CLIgnoredFlag<"nologo">;
-def _SLASH_Ob1 : CLIgnoredFlag<"Ob1">;
 def _SLASH_Og : CLIgnoredFlag<"Og">;
 def _SLASH_openmp_ : CLIgnoredFlag<"openmp-">;
 def _SLASH_RTC : CLIgnoredJoined<"RTC">;

clang/include/clang/Driver/Options.td

@@ -746,7 +746,10 @@ def fgnu_runtime : Flag<["-"], "fgnu-runtime">, Group<f_Group>,
 def fheinous_gnu_extensions : Flag<["-"], "fheinous-gnu-extensions">, Flags<[CC1Option]>;
 def filelist : Separate<["-"], "filelist">, Flags<[LinkerInput]>;
 def : Flag<["-"], "findirect-virtual-calls">, Alias<fapple_kext>;
-def finline_functions : Flag<["-"], "finline-functions">, Group<f_clang_Group>, Flags<[CC1Option]>;
+def finline_functions : Flag<["-"], "finline-functions">, Group<f_clang_Group>, Flags<[CC1Option]>,
+  HelpText<"Inline suitable functions">;
+def finline_hint_functions: Flag<["-"], "finline-hint-functions">, Group<f_clang_Group>, Flags<[CC1Option]>,
+  HelpText<"Inline functions wich are (explicitly or implicitly) marked inline">;
 def finline : Flag<["-"], "finline">, Group<clang_ignored_f_Group>;
 def finput_charset_EQ : Joined<["-"], "finput-charset=">, Group<f_Group>;
 def fexec_charset_EQ : Joined<["-"], "fexec-charset=">, Group<f_Group>;

clang/include/clang/Frontend/CodeGenOptions.h

@@ -46,6 +46,7 @@ public:
   enum InliningMethod {
     NoInlining,         // Perform no inlining whatsoever.
     NormalInlining,     // Use the standard function inlining pass.
+    OnlyHintInlining,   // Inline only (implicitly) hinted functions.
     OnlyAlwaysInlining  // Only run the always inlining pass.
   };
 

clang/lib/CodeGen/BackendUtil.cpp

@@ -328,7 +328,8 @@ void EmitAssemblyHelper::CreatePasses(ModuleSummaryIndex *ModuleSummary) {
   switch (Inlining) {
   case CodeGenOptions::NoInlining:
     break;
-  case CodeGenOptions::NormalInlining: {
+  case CodeGenOptions::NormalInlining:
+  case CodeGenOptions::OnlyHintInlining: {
     PMBuilder.Inliner =
         createFunctionInliningPass(OptLevel, CodeGenOpts.OptimizeSize);
     break;

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -686,14 +686,20 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
 
   // Pass inline keyword to optimizer if it appears explicitly on any
   // declaration. Also, in the case of -fno-inline attach NoInline
-  // attribute to all function that are not marked AlwaysInline.
+  // attribute to all functions that are not marked AlwaysInline, or
+  // to all functions that are not marked inline or implicitly inline
+  // in the case of -finline-hint-functions.
   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) {
-    if (!CGM.getCodeGenOpts().NoInline) {
+    const CodeGenOptions& CodeGenOpts = CGM.getCodeGenOpts();
+    if (!CodeGenOpts.NoInline) {
       for (auto RI : FD->redecls())
         if (RI->isInlineSpecified()) {
           Fn->addFnAttr(llvm::Attribute::InlineHint);
           break;
         }
+      if (CodeGenOpts.getInlining() == CodeGenOptions::OnlyHintInlining &&
+          !FD->isInlined() && !Fn->hasFnAttribute(llvm::Attribute::InlineHint))
+        Fn->addFnAttr(llvm::Attribute::NoInline);
     } else if (!FD->hasAttr<AlwaysInlineAttr>())
       Fn->addFnAttr(llvm::Attribute::NoInline);
     if (CGM.getLangOpts().OpenMP && FD->hasAttr<OMPDeclareSimdDeclAttr>())

clang/lib/Driver/MSVCToolChain.cpp

@@ -728,7 +728,7 @@ static void TranslateOptArg(Arg *A, llvm::opt::DerivedArgList &DAL,
           DAL.AddFlagArg(A, Opts.getOption(options::OPT_fno_inline));
           break;
         case '1':
-          // TODO: Inline calls to 'inline functions' only.
+          DAL.AddFlagArg(A, Opts.getOption(options::OPT_finline_hint_functions));
           break;
         case '2':
           DAL.AddFlagArg(A, Opts.getOption(options::OPT_finline_functions));

clang/lib/Driver/Tools.cpp

@@ -5405,6 +5405,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-fno-inline");
 
   if (Arg* InlineArg = Args.getLastArg(options::OPT_finline_functions,
+                                       options::OPT_finline_hint_functions,
                                        options::OPT_fno_inline_functions))
     InlineArg->render(Args, CmdArgs);
 

clang/lib/Frontend/CompilerInvocation.cpp

@@ -442,10 +442,15 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   // -fno-inline-functions overrides OptimizationLevel > 1.
   Opts.NoInline = Args.hasArg(OPT_fno_inline);
   if (Arg* InlineArg = Args.getLastArg(options::OPT_finline_functions,
+                                       options::OPT_finline_hint_functions,
                                        options::OPT_fno_inline_functions)) {
-    Opts.setInlining(
-      InlineArg->getOption().matches(options::OPT_finline_functions) ?
-        CodeGenOptions::NormalInlining : CodeGenOptions::OnlyAlwaysInlining);
+    const Option& InlineOpt = InlineArg->getOption();
+    if (InlineOpt.matches(options::OPT_finline_functions))
+      Opts.setInlining(CodeGenOptions::NormalInlining);
+    else if (InlineOpt.matches(options::OPT_finline_hint_functions))
+      Opts.setInlining(CodeGenOptions::OnlyHintInlining);
+    else
+      Opts.setInlining(CodeGenOptions::OnlyAlwaysInlining);
   }
 
   if (Arg *A = Args.getLastArg(OPT_fveclib)) {

clang/test/CodeGen/inline-optim.c

@@ -2,6 +2,7 @@
 
 // RUN: %clang_cc1 -triple i686-pc-win32 -emit-llvm %s -o - | FileCheck -check-prefix=NOINLINE %s
 // RUN: %clang_cc1 -triple i686-pc-win32 -O3 -fno-inline-functions -emit-llvm %s -o - | FileCheck -check-prefix=NOINLINE %s
+// RUN: %clang_cc1 -triple i686-pc-win32 -finline-hint-functions -emit-llvm %s -o - | FileCheck -check-prefix=HINT %s
 // RUN: %clang_cc1 -triple i686-pc-win32 -finline-functions -emit-llvm %s -o - | FileCheck -check-prefix=INLINE %s
 
 inline int inline_hint(int a, int b) { return(a+b); }
@@ -13,14 +14,18 @@ inline __attribute__ ((__always_inline__)) int inline_always(int a, int b) { ret
 volatile int *pa = (int*) 0x1000;
 void foo() {
 // NOINLINE-LABEL: @foo
+// HINT-LABEL: @foo
 // INLINE-LABEL: @foo
 // NOINLINE: call i32 @inline_hint
+// HINT-NOT: call i32 @inline_hint
 // INLINE-NOT: call i32 @inline_hint
     pa[0] = inline_hint(pa[1],pa[2]);
 // NOINLINE-NOT: call i32 @inline_always
+// HINT-NOT: call i32 @inline_always
 // INLINE-NOT: call i32 @inline_always
     pa[3] = inline_always(pa[4],pa[5]);
 // NOINLINE: call i32 @inline_no_hint
+// HINT: call i32 @inline_no_hint
 // INLINE-NOT: call i32 @inline_no_hint
     pa[6] = inline_no_hint(pa[7], pa[8]);
 }

clang/test/CodeGenCXX/inline-hint.cpp

@@ -0,0 +1,96 @@
+// RUN: %clang_cc1 %s -std=c++11 -triple=x86_64-linux -finline-functions -emit-llvm -disable-llvm-optzns -o - | FileCheck %s --check-prefix=CHECK --check-prefix=SUITABLE
+// RUN: %clang_cc1 %s -std=c++11 -triple=x86_64-linux -finline-hint-functions -emit-llvm -disable-llvm-optzns -o - | FileCheck %s --check-prefix=CHECK --check-prefix=HINTED
+// RUN: %clang_cc1 %s -std=c++11 -triple=x86_64-linux -fno-inline -emit-llvm -disable-llvm-optzns -o - | FileCheck %s --check-prefix=CHECK --check-prefix=NOINLINE
+
+// Force non-trivial implicit constructors/destructors/operators for B by having explicit ones for A
+struct A {
+  A() {}
+  A(const A&) {}
+  A& operator=(const A&) { return *this; }
+  ~A() {}
+};
+
+struct B {
+  A member;
+  int implicitFunction(int a) { return a + a; }
+  inline int explicitFunction(int a);
+  int noHintFunction(int a);
+  __attribute__((optnone)) int optNoneFunction(int a) { return a + a; }
+  template<int N> int implicitTplFunction(int a) { return N + a; }
+  template<int N> inline int explicitTplFunction(int a) { return N + a; }
+  template<int N> int noHintTplFunction(int a);
+  template<int N> int explicitRedeclTplFunction(int a);
+};
+
+int B::explicitFunction(int a) { return a + a; }
+// CHECK: @_ZN1B14noHintFunctionEi({{.*}}) [[NOHINT_ATTR:#[0-9]+]]
+int B::noHintFunction(int a) { return a + a; }
+
+// CHECK: @_ZN1B19implicitTplFunctionILi0EEEii({{.*}}) [[NOHINT_ATTR]]
+template<> int B::implicitTplFunction<0>(int a) { return a + a; }
+// CHECK: @_ZN1B19explicitTplFunctionILi0EEEii({{.*}}) [[NOHINT_ATTR]]
+template<> int B::explicitTplFunction<0>(int a) { return a + a; }
+// CHECK: @_ZN1B17noHintTplFunctionILi0EEEii({{.*}}) [[NOHINT_ATTR]]
+template<> int B::noHintTplFunction<0>(int a) { return a + a; }
+template<> inline int B::implicitTplFunction<1>(int a) { return a; }
+template<> inline int B::explicitTplFunction<1>(int a) { return a; }
+template<> inline int B::noHintTplFunction<1>(int a) { return a; }
+template<int N> int B::noHintTplFunction(int a) { return N + a; }
+template<int N> inline int B::explicitRedeclTplFunction(int a) { return N + a; }
+
+constexpr int constexprFunction(int a) { return a + a; }
+
+void foo()
+{
+// CHECK: @_ZN1BC1Ev({{.*}}) unnamed_addr [[IMPLICIT_CONSTR_ATTR:#[0-9]+]]
+  B b1;
+// CHECK: @_ZN1BC1ERKS_({{.*}}) unnamed_addr [[IMPLICIT_CONSTR_ATTR]]
+  B b2(b1);
+// CHECK: @_ZN1BaSERKS_({{.*}}) [[IMPLICIT_CONSTR_ATTR]]
+  b2 = b1;
+// CHECK: @_ZN1B16implicitFunctionEi({{.*}}) [[IMPLICIT_ATTR:#[0-9]+]]
+  b1.implicitFunction(1);
+// CHECK: @_ZN1B16explicitFunctionEi({{.*}}) [[EXPLICIT_ATTR:#[0-9]+]]
+  b1.explicitFunction(2);
+  b1.noHintFunction(3);
+// CHECK: @_ZN1B15optNoneFunctionEi({{.*}}) [[OPTNONE_ATTR:#[0-9]+]]
+  b1.optNoneFunction(4);
+// CHECK: @_Z17constexprFunctioni({{.*}}) [[IMPLICIT_ATTR]]
+  constexprFunction(5);
+  b1.implicitTplFunction<0>(6);
+// CHECK: @_ZN1B19implicitTplFunctionILi1EEEii({{.*}}) [[EXPLICIT_ATTR]]
+  b1.implicitTplFunction<1>(7);
+// CHECK: @_ZN1B19implicitTplFunctionILi2EEEii({{.*}}) [[IMPLICIT_ATTR]]
+  b1.implicitTplFunction<2>(8);
+  b1.explicitTplFunction<0>(9);
+// CHECK: @_ZN1B19explicitTplFunctionILi1EEEii({{.*}}) [[EXPLICIT_ATTR]]
+  b1.explicitTplFunction<1>(10);
+// CHECK: @_ZN1B19explicitTplFunctionILi2EEEii({{.*}}) [[EXPLICIT_ATTR]]
+  b1.explicitTplFunction<2>(11);
+  b1.noHintTplFunction<0>(12);
+// CHECK: @_ZN1B17noHintTplFunctionILi1EEEii({{.*}}) [[EXPLICIT_ATTR]]
+  b1.noHintTplFunction<1>(13);
+// CHECK: @_ZN1B17noHintTplFunctionILi2EEEii({{.*}}) [[NOHINT_ATTR]]
+  b1.noHintTplFunction<2>(14);
+// CHECK: @_ZN1B25explicitRedeclTplFunctionILi2EEEii({{.*}}) [[EXPLICIT_ATTR]]
+  b1.explicitRedeclTplFunction<2>(15);
+// CHECK: @_ZN1BD2Ev({{.*}}) unnamed_addr [[IMPLICIT_CONSTR_ATTR]]
+}
+
+// SUITABLE-NOT: attributes [[NOHINT_ATTR]] = { {{.*}}noinline{{.*}} }
+//   HINTED-DAG: attributes [[NOHINT_ATTR]] = { noinline{{.*}} }
+// NOINLINE-DAG: attributes [[NOHINT_ATTR]] = { noinline{{.*}} }
+
+// SUITABLE-NOT: attributes [[IMPLICIT_ATTR]] = { {{.*}}noinline{{.*}} }
+//   HINTED-NOT: attributes [[IMPLICIT_ATTR]] = { {{.*}}noinline{{.*}} }
+// NOINLINE-DAG: attributes [[IMPLICIT_ATTR]] = { noinline{{.*}} }
+
+// SUITABLE-NOT: attributes [[IMPLICIT_CONSTR_ATTR]] = { {{.*}}noinline{{.*}} }
+//   HINTED-NOT: attributes [[IMPLICIT_ATTR]] = { {{.*}}noinline{{.*}} }
+// NOINLINE-DAG: attributes [[IMPLICIT_CONSTR_ATTR]] = { noinline{{.*}} }
+
+// SUITABLE-NOT: attributes [[EXPLICIT_ATTR]] = { {{.*}}noinline{{.*}} }
+//   HINTED-NOT: attributes [[IMPLICIT_ATTR]] = { {{.*}}noinline{{.*}} }
+// NOINLINE-DAG: attributes [[EXPLICIT_ATTR]] = { noinline{{.*}} }
+
+// CHECK-DAG: attributes [[OPTNONE_ATTR]] = { noinline{{.*}} }

clang/test/Driver/cl-options.c

@@ -113,6 +113,10 @@
 // Ob2-NOT: warning: argument unused during compilation: '/O2'
 // Ob2: -finline-functions
 
+// RUN: %clang_cl /Ob1 -### -- %s 2>&1 | FileCheck -check-prefix=Ob1 %s
+// RUN: %clang_cl /Odb1 -### -- %s 2>&1 | FileCheck -check-prefix=Ob1 %s
+// Ob1: -finline-hint-functions
+
 // RUN: %clang_cl /Od -### -- %s 2>&1 | FileCheck -check-prefix=Od %s
 // Od: -O0
 
@@ -280,7 +284,6 @@
 // RUN:    /GS- \
 // RUN:    /kernel- \
 // RUN:    /nologo \
-// RUN:    /Ob1 \
 // RUN:    /openmp- \
 // RUN:    /RTC1 \
 // RUN:    /sdl \