IR: Replace the "Linker Options" module flag with "llvm.linker.option…

…s" named metadata.

The new metadata is easier to manipulate than module flags.

Differential Revision: https://reviews.llvm.org/D31349

llvm-svn: 305227

clang/lib/CodeGen/CodeGenModule.cpp

@@ -1243,7 +1243,7 @@ void CodeGenModule::AddDependentLib(StringRef Lib) {
 /// \brief Add link options implied by the given module, including modules
 /// it depends on, using a postorder walk.
 static void addLinkOptionsPostorder(CodeGenModule &CGM, Module *Mod,
-                                    SmallVectorImpl<llvm::Metadata *> &Metadata,
+                                    SmallVectorImpl<llvm::MDNode *> &Metadata,
                                     llvm::SmallPtrSet<Module *, 16> &Visited) {
   // Import this module's parent.
   if (Mod->Parent && Visited.insert(Mod->Parent).second) {
@@ -1331,7 +1331,7 @@ void CodeGenModule::EmitModuleLinkOptions() {
   // Add link options for all of the imported modules in reverse topological
   // order.  We don't do anything to try to order import link flags with respect
   // to linker options inserted by things like #pragma comment().
-  SmallVector<llvm::Metadata *, 16> MetadataArgs;
+  SmallVector<llvm::MDNode *, 16> MetadataArgs;
   Visited.clear();
   for (Module *M : LinkModules)
     if (Visited.insert(M).second)
@@ -1340,9 +1340,9 @@ void CodeGenModule::EmitModuleLinkOptions() {
   LinkerOptionsMetadata.append(MetadataArgs.begin(), MetadataArgs.end());
 
   // Add the linker options metadata flag.
-  getModule().addModuleFlag(llvm::Module::AppendUnique, "Linker Options",
-                            llvm::MDNode::get(getLLVMContext(),
-                                              LinkerOptionsMetadata));
+  auto *NMD = getModule().getOrInsertNamedMetadata("llvm.linker.options");
+  for (auto *MD : LinkerOptionsMetadata)
+    NMD->addOperand(MD);
 }
 
 void CodeGenModule::EmitDeferred() {

clang/lib/CodeGen/CodeGenModule.h

@@ -429,7 +429,7 @@ class CodeGenModule : public CodeGenTypeCache {
   llvm::SmallPtrSet<clang::Module *, 16> EmittedModuleInitializers;
 
   /// \brief A vector of metadata strings.
-  SmallVector<llvm::Metadata *, 16> LinkerOptionsMetadata;
+  SmallVector<llvm::MDNode *, 16> LinkerOptionsMetadata;
 
   /// @name Cache for Objective-C runtime types
   /// @{
@@ -1058,13 +1058,14 @@ class CodeGenModule : public CodeGenTypeCache {
 
   void RefreshTypeCacheForClass(const CXXRecordDecl *Class);
 
-  /// \brief Appends Opts to the "Linker Options" metadata value.
+  /// \brief Appends Opts to the "llvm.linker.options" metadata value.
   void AppendLinkerOptions(StringRef Opts);
 
   /// \brief Appends a detect mismatch command to the linker options.
   void AddDetectMismatch(StringRef Name, StringRef Value);
 
-  /// \brief Appends a dependent lib to the "Linker Options" metadata value.
+  /// \brief Appends a dependent lib to the "llvm.linker.options" metadata
+  /// value.
   void AddDependentLib(StringRef Lib);
 
   llvm::GlobalVariable::LinkageTypes getFunctionLinkage(GlobalDecl GD);

clang/test/CodeGen/dependent-lib.c

@@ -3,14 +3,10 @@
 // RUN: %clang_cc1 %s --dependent-lib=msvcrt -triple x86_64-pc-win32 -emit-llvm -o - | FileCheck %s
 // RUN: %clang_cc1 %s --dependent-lib=msvcrt -triple i686-pc-linux -emit-llvm -o - | FileCheck -check-prefix LINUX %s
 
-// CHECK: !llvm.module.flags = !{{{.*}}}
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[link_opts:[0-9]+]]}
-// CHECK: ![[link_opts]] = !{![[msvcrt:[0-9]+]]}
+// CHECK: !llvm.linker.options = !{![[msvcrt:[0-9]+]]}
 // CHECK: ![[msvcrt]] = !{!"/DEFAULTLIB:msvcrt.lib"}
 
-// LINUX: !llvm.module.flags = !{{{.*}}}
-// LINUX: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[link_opts:[0-9]+]]}
-// LINUX: ![[link_opts]] = !{![[msvcrt:[0-9]+]]}
+// LINUX: !llvm.linker.options = !{![[msvcrt:[0-9]+]]}
 // LINUX: ![[msvcrt]] = !{!"-lmsvcrt"}
 
 int f();

clang/test/CodeGen/linker-option.c

@@ -1,8 +1,6 @@
 // RUN: %clang_cc1 %s --linker-option=/include:foo -triple i686-pc-win32 -emit-llvm -o - | FileCheck %s
 
-// CHECK: !llvm.module.flags = !{{{.*}}}
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[link_opts:[0-9]+]]}
-// CHECK: ![[link_opts]] = !{![[msvcrt:[0-9]+]]}
+// CHECK: !llvm.linker.options = !{![[msvcrt:[0-9]+]]}
 // CHECK: ![[msvcrt]] = !{!"/include:foo"}
 
 int f();

clang/test/CodeGen/pragma-comment.c

@@ -14,9 +14,7 @@
 #pragma comment(linker," /bar=" BAR)
 #pragma comment(linker," /foo=\"foo bar\"")
 
-// CHECK: !llvm.module.flags = !{{{.*}}}
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[link_opts:[0-9]+]]}
-// CHECK: ![[link_opts]] = !{![[msvcrt:[0-9]+]], ![[kernel32:[0-9]+]], ![[USER32:[0-9]+]], ![[space:[0-9]+]], ![[bar:[0-9]+]], ![[foo:[0-9]+]]}
+// CHECK: !llvm.linker.options = !{![[msvcrt:[0-9]+]], ![[kernel32:[0-9]+]], ![[USER32:[0-9]+]], ![[space:[0-9]+]], ![[bar:[0-9]+]], ![[foo:[0-9]+]]}
 // CHECK: ![[msvcrt]] = !{!"/DEFAULTLIB:msvcrt.lib"}
 // CHECK: ![[kernel32]] = !{!"/DEFAULTLIB:kernel32.lib"}
 // CHECK: ![[USER32]] = !{!"/DEFAULTLIB:USER32.LIB"}

clang/test/CodeGen/pragma-detect_mismatch.c

@@ -6,8 +6,6 @@
 #define BAR "2"
 #pragma detect_mismatch("test2", BAR)
 
-// CHECK: !llvm.module.flags = !{{{.*}}}
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[link_opts:[0-9]+]]}
-// CHECK: ![[link_opts]] = !{![[test:[0-9]+]], ![[test2:[0-9]+]]}
+// CHECK: !llvm.linker.options = !{![[test:[0-9]+]], ![[test2:[0-9]+]]}
 // CHECK: ![[test]] = !{!"/FAILIFMISMATCH:\22test=1\22"}
 // CHECK: ![[test2]] = !{!"/FAILIFMISMATCH:\22test2=2\22"}

clang/test/CodeGenCXX/ms-thread_local.cpp

@@ -27,7 +27,5 @@ A f() {
   return c;
 }
 
-// CHECK: !llvm.module.flags = !{{{.*}}}
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[link_opts:[0-9]+]]}
-// CHECK: ![[link_opts]] = !{![[dyn_tls_init:[0-9]+]]}
+// CHECK: !llvm.linker.options = !{![[dyn_tls_init:[0-9]+]]}
 // CHECK: ![[dyn_tls_init]] = !{!"/include:___dyn_tls_init@12"}

clang/test/CodeGenObjC/availability-cf-link-guard.m

@@ -37,9 +37,8 @@ void use_at_available() {
 // CHECK_NO_GUARD-NOT: __clang_at_available_requires_core_foundation_framework
 // CHECK_NO_GUARD-NOT: CFBundleGetVersionNumber
 
-// CHECK_LINK_OPT: !"Linker Options", ![[OPTS:[0-9]+]]
-// CHECK_LINK_OPT: ![[OPTS]] = !{![[FRAMEWORK:[0-9]+]]
+// CHECK_LINK_OPT: !llvm.linker.options = !{![[FRAMEWORK:[0-9]+]]
 // CHECK_LINK_OPT: ![[FRAMEWORK]] = !{!"-framework", !"CoreFoundation"}
 
-// CHECK_NO_GUARD-NOT: "Linker Options"
+// CHECK_NO_GUARD-NOT: !llvm.linker.options
 // CHECK_NO_GUARD-NOT: CoreFoundation

clang/test/Modules/autolink.m

@@ -36,9 +36,7 @@ int use_autolink_sub3() {
 
 // NOTE: "autolink_sub" is intentionally not linked.
 
-// CHECK: !llvm.module.flags = !{{{.*}}}
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[AUTOLINK_OPTIONS:[0-9]+]]}
-// CHECK: ![[AUTOLINK_OPTIONS]] = !{![[AUTOLINK_PCH:[0-9]+]], ![[AUTOLINK_FRAMEWORK:[0-9]+]], ![[AUTOLINK:[0-9]+]], ![[DEPENDSONMODULE:[0-9]+]], ![[MODULE:[0-9]+]], ![[NOUMBRELLA:[0-9]+]]}
+// CHECK: !llvm.linker.options = !{![[AUTOLINK_PCH:[0-9]+]], ![[AUTOLINK_FRAMEWORK:[0-9]+]], ![[AUTOLINK:[0-9]+]], ![[DEPENDSONMODULE:[0-9]+]], ![[MODULE:[0-9]+]], ![[NOUMBRELLA:[0-9]+]]}
 // CHECK: ![[AUTOLINK_PCH]] = !{!"{{(\\01|-l|/DEFAULTLIB:)}}autolink_from_pch{{(\.lib)?}}"}
 // CHECK: ![[AUTOLINK_FRAMEWORK]] = !{!"-framework", !"autolink_framework"}
 // CHECK: ![[AUTOLINK]] = !{!"{{(\\01|-l|/DEFAULTLIB:)}}autolink{{(\.lib)?}}"}
@@ -47,4 +45,4 @@ int use_autolink_sub3() {
 // CHECK: ![[NOUMBRELLA]] = !{!"-framework", !"NoUmbrella"}
 
 // CHECK-AUTOLINK-DISABLED: !llvm.module.flags
-// CHECK-AUTOLINK-DISABLED-NOT: "Linker Options"
+// CHECK-AUTOLINK-DISABLED-NOT: !llvm.linker.options

clang/test/Modules/autolinkTBD.m

@@ -8,10 +8,8 @@ int f() {
   return foo();
 }
 
-// CHECK: !llvm.module.flags = !{{{.*}}}
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[AUTOLINK_OPTIONS:[0-9]+]]}
-// CHECK: ![[AUTOLINK_OPTIONS]] = !{![[AUTOLINK_FRAMEWORK:[0-9]+]]}
+// CHECK: !llvm.linker.options = !{![[AUTOLINK_FRAMEWORK:[0-9]+]]}
 // CHECK: ![[AUTOLINK_FRAMEWORK]] = !{!"-framework", !"AutolinkTBD"}
 
 // CHECK-AUTOLINK-DISABLED: !llvm.module.flags
-// CHECK-AUTOLINK-DISABLED-NOT: "Linker Options"
+// CHECK-AUTOLINK-DISABLED-NOT: !llvm.linker.options

clang/test/Modules/module-impl-with-link.c

@@ -1,7 +1,6 @@
 // RUN: rm -rf %t
 // RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -fmodule-name=Clib %s -I %S/Inputs/module-impl-with-link -emit-llvm -o - | FileCheck %s
 #include "foo.h"
-// CHECK: !{{[0-9]+}} = !{i32 6, !"Linker Options", ![[LINK_OPTIONS:[0-9]+]]}
 // Make sure we don't generate linker option for module Clib since this TU is
 // an implementation of Clib.
-// CHECK: ![[LINK_OPTIONS]] = !{}
+// CHECK: !llvm.linker.options = !{}

lld/test/COFF/Inputs/constant-export.ll

@@ -3,8 +3,5 @@ target triple = "i686-unknown-windows-msvc18.0.0"
 
 @__CFConstantStringClassReference = common global [32 x i32] zeroinitializer, align 4
 
-!llvm.module.flags = !{!0}
-
-!0 = !{i32 6, !"Linker Options", !1}
-!1 = !{!2}
-!2 = !{!" -export:___CFConstantStringClassReference,CONSTANT"}
+!llvm.linker.options = !{!0}
+!0 = !{!" -export:___CFConstantStringClassReference,CONSTANT"}

lld/test/COFF/include-lto.ll

@@ -17,8 +17,5 @@ define i32 @foo() {
   ret i32 0
 }
 
-!llvm.module.flags = !{!0}
-
-!0 = !{i32 6, !"Linker Options", !1}
-!1 = !{!2}
-!2 = !{!"/INCLUDE:foo"}
+!llvm.linker.options = !{!0}
+!0 = !{!"/INCLUDE:foo"}

lld/test/COFF/lto-linker-opts.ll

@@ -4,8 +4,5 @@
 target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-windows-msvc"
 
-!llvm.module.flags = !{!0}
-
-!0 = !{i32 6, !"Linker Options", !1}
-!1 = !{!2}
-!2 = !{!"/DEFAULTLIB:ret42.lib"}
+!llvm.linker.options = !{!0}
+!0 = !{!"/DEFAULTLIB:ret42.lib"}

llvm/docs/LangRef.rst

@@ -5352,40 +5352,6 @@ Some important flag interactions:
 -  A module with ``Objective-C Garbage Collection`` set to 0 cannot be
    merged with a module with ``Objective-C GC Only`` set to 6.
 
-Automatic Linker Flags Module Flags Metadata
---------------------------------------------
-
-Some targets support embedding flags to the linker inside individual object
-files. Typically this is used in conjunction with language extensions which
-allow source files to explicitly declare the libraries they depend on, and have
-these automatically be transmitted to the linker via object files.
-
-These flags are encoded in the IR using metadata in the module flags section,
-using the ``Linker Options`` key. The merge behavior for this flag is required
-to be ``AppendUnique``, and the value for the key is expected to be a metadata
-node which should be a list of other metadata nodes, each of which should be a
-list of metadata strings defining linker options.
-
-For example, the following metadata section specifies two separate sets of
-linker options, presumably to link against ``libz`` and the ``Cocoa``
-framework::
-
-    !0 = !{ i32 6, !"Linker Options",
-       !{
-          !{ !"-lz" },
-          !{ !"-framework", !"Cocoa" } } }
-    !llvm.module.flags = !{ !0 }
-
-The metadata encoding as lists of lists of options, as opposed to a collapsed
-list of options, is chosen so that the IR encoding can use multiple option
-strings to specify e.g., a single library, while still having that specifier be
-preserved as an atomic element that can be recognized by a target specific
-assembly writer or object file emitter.
-
-Each individual option is required to be either a valid option for the target's
-linker, or an option that is reserved by the target specific assembly writer or
-object file emitter. No other aspect of these options is defined by the IR.
-
 C type width Module Flags Metadata
 ----------------------------------
 
@@ -5422,6 +5388,37 @@ enum is the smallest type which can represent all of its values::
     !0 = !{i32 1, !"short_wchar", i32 1}
     !1 = !{i32 1, !"short_enum", i32 0}
 
+Automatic Linker Flags Named Metadata
+=====================================
+
+Some targets support embedding flags to the linker inside individual object
+files. Typically this is used in conjunction with language extensions which
+allow source files to explicitly declare the libraries they depend on, and have
+these automatically be transmitted to the linker via object files.
+
+These flags are encoded in the IR using named metadata with the name
+``!llvm.linker.options``. Each operand is expected to be a metadata node
+which should be a list of other metadata nodes, each of which should be a
+list of metadata strings defining linker options.
+
+For example, the following metadata section specifies two separate sets of
+linker options, presumably to link against ``libz`` and the ``Cocoa``
+framework::
+
+    !0 = !{ !"-lz" },
+    !1 = !{ !"-framework", !"Cocoa" } } }
+    !llvm.linker.options = !{ !0, !1 }
+
+The metadata encoding as lists of lists of options, as opposed to a collapsed
+list of options, is chosen so that the IR encoding can use multiple option
+strings to specify e.g., a single library, while still having that specifier be
+preserved as an atomic element that can be recognized by a target specific
+assembly writer or object file emitter.
+
+Each individual option is required to be either a valid option for the target's
+linker, or an option that is reserved by the target specific assembly writer or
+object file emitter. No other aspect of these options is defined by the IR.
+
 .. _intrinsicglobalvariables:
 
 Intrinsic Global Variables

llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h

@@ -42,9 +42,8 @@ class TargetLoweringObjectFileELF : public TargetLoweringObjectFile {
   ~TargetLoweringObjectFileELF() override = default;
 
   /// Emit Obj-C garbage collection and linker options.
-  void emitModuleFlags(MCStreamer &Streamer,
-                       ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
-                       const TargetMachine &TM) const override;
+  void emitModuleMetadata(MCStreamer &Streamer, Module &M,
+                          const TargetMachine &TM) const override;
 
   void emitPersonalityValue(MCStreamer &Streamer, const DataLayout &TM,
                             const MCSymbol *Sym) const override;
@@ -99,9 +98,8 @@ class TargetLoweringObjectFileMachO : public TargetLoweringObjectFile {
   void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
 
   /// Emit the module flags that specify the garbage collection information.
-  void emitModuleFlags(MCStreamer &Streamer,
-                       ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
-                       const TargetMachine &TM) const override;
+  void emitModuleMetadata(MCStreamer &Streamer, Module &M,
+                          const TargetMachine &TM) const override;
 
   MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
                                     const TargetMachine &TM) const override;
@@ -155,9 +153,8 @@ class TargetLoweringObjectFileCOFF : public TargetLoweringObjectFile {
                                     const TargetMachine &TM) const override;
 
   /// Emit Obj-C garbage collection and linker options.
-  void emitModuleFlags(MCStreamer &Streamer,
-                       ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
-                       const TargetMachine &TM) const override;
+  void emitModuleMetadata(MCStreamer &Streamer, Module &M,
+                          const TargetMachine &TM) const override;
 
   MCSection *getStaticCtorSection(unsigned Priority,
                                   const MCSymbol *KeySym) const override;

llvm/include/llvm/LTO/legacy/LTOModule.h

@@ -158,7 +158,7 @@ struct LTOModule {
 
 private:
   /// Parse metadata from the module
-  // FIXME: it only parses "Linker Options" metadata at the moment
+  // FIXME: it only parses "llvm.linker.options" metadata at the moment
   void parseMetadata();
 
   /// Parse the symbols from the module and model-level ASM and add them to

llvm/include/llvm/Target/TargetLoweringObjectFile.h

@@ -70,10 +70,9 @@ class TargetLoweringObjectFile : public MCObjectFileInfo {
   virtual void emitPersonalityValue(MCStreamer &Streamer, const DataLayout &TM,
                                     const MCSymbol *Sym) const;
 
-  /// Emit the module flags that the platform cares about.
-  virtual void emitModuleFlags(MCStreamer &Streamer,
-                               ArrayRef<Module::ModuleFlagEntry> Flags,
-                               const TargetMachine &TM) const {}
+  /// Emit the module-level metadata that the platform cares about.
+  virtual void emitModuleMetadata(MCStreamer &Streamer, Module &M,
+                                  const TargetMachine &TM) const {}
 
   /// Given a constant with the SectionKind, return a section that it should be
   /// placed in.

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -2608,6 +2608,16 @@ Error BitcodeReader::materializeMetadata() {
     if (Error Err = MDLoader->parseModuleMetadata())
       return Err;
   }
+
+  // Upgrade "Linker Options" module flag to "llvm.linker.options" module-level
+  // metadata.
+  if (Metadata *Val = TheModule->getModuleFlag("Linker Options")) {
+    NamedMDNode *LinkerOpts =
+        TheModule->getOrInsertNamedMetadata("llvm.linker.options");
+    for (const MDOperand &MDOptions : cast<MDNode>(Val)->operands())
+      LinkerOpts->addOperand(cast<MDNode>(MDOptions));
+  }
+
   DeferredMetadataInfo.clear();
   return Error::success();
 }

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -1286,11 +1286,7 @@ bool AsmPrinter::doFinalization(Module &M) {
 
   const TargetLoweringObjectFile &TLOF = getObjFileLowering();
 
-  // Emit module flags.
-  SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
-  M.getModuleFlagsMetadata(ModuleFlags);
-  if (!ModuleFlags.empty())
-    TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, TM);
+  TLOF.emitModuleMetadata(*OutStreamer, M, TM);
 
   if (TM.getTargetTriple().isOSBinFormatELF()) {
     MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();