CodeGen: add support for emitting ObjC image info

This ensures that we can emit the ObjC Image Info structure on COFF and
ELF as well.  The frontend already would attempt to emit this
information but would get dropped when generating assembly or an object
file.

llvm-svn: 304736

5 files changed, 118 insertions, 25 deletions

diff --git a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
index adf2b3e..106a084 100644
--- a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
+++ b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
@@ -41,6 +41,11 @@ public:
   TargetLoweringObjectFileELF() = default;
   ~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 emitPersonalityValue(MCStreamer &Streamer, const DataLayout &TM,
                             const MCSymbol *Sym) const override;
 
@@ -149,8 +154,7 @@ public:
   MCSection *getSectionForJumpTable(const Function &F,
                                     const TargetMachine &TM) const override;
 
-  /// Emit Obj-C garbage collection and linker options. Only linker option
-  /// emission is implemented for COFF.
+  /// Emit Obj-C garbage collection and linker options.
   void emitModuleFlags(MCStreamer &Streamer,
                        ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
                        const TargetMachine &TM) const override;
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 3ba4a3a..24baa59 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -61,10 +61,53 @@
 using namespace llvm;
 using namespace dwarf;
 
+static void GetObjCImageInfo(ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
+                             unsigned &Version, unsigned &Flags,
+                             StringRef &Section) {
+  for (const auto &MFE: ModuleFlags) {
+    // Ignore flags with 'Require' behaviour.
+    if (MFE.Behavior == Module::Require)
+      continue;
+
+    StringRef Key = MFE.Key->getString();
+    if (Key == "Objective-C Image Info Version") {
+      Version = mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue();
+    } else if (Key == "Objective-C Garbage Collection" ||
+               Key == "Objective-C GC Only" ||
+               Key == "Objective-C Is Simulated" ||
+               Key == "Objective-C Class Properties" ||
+               Key == "Objective-C Image Swift Version") {
+      Flags |= mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue();
+    } else if (Key == "Objective-C Image Info Section") {
+      Section = cast<MDString>(MFE.Val)->getString();
+    }
+  }
+}
+
 //===----------------------------------------------------------------------===//
 //                                  ELF
 //===----------------------------------------------------------------------===//
 
+void TargetLoweringObjectFileELF::emitModuleFlags(
+    MCStreamer &Streamer, ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
+    const TargetMachine &TM) const {
+  unsigned Version = 0;
+  unsigned Flags = 0;
+  StringRef Section;
+
+  GetObjCImageInfo(ModuleFlags, Version, Flags, Section);
+  if (Section.empty())
+    return;
+
+  auto &C = getContext();
+  auto *S = C.getELFSection(Section, ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
+  Streamer.SwitchSection(S);
+  Streamer.EmitLabel(C.getOrCreateSymbol(StringRef("OBJC_IMAGE_INFO")));
+  Streamer.EmitIntValue(Version, 4);
+  Streamer.EmitIntValue(Flags, 4);
+  Streamer.AddBlankLine();
+}
+
 MCSymbol *TargetLoweringObjectFileELF::getCFIPersonalitySymbol(
     const GlobalValue *GV, const TargetMachine &TM,
     MachineModuleInfo *MMI) const {
@@ -579,32 +622,12 @@ void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
 void TargetLoweringObjectFileMachO::emitModuleFlags(
     MCStreamer &Streamer, ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
     const TargetMachine &TM) const {
-  unsigned VersionVal = 0;
-  unsigned ImageInfoFlags = 0;
   MDNode *LinkerOptions = nullptr;
-  StringRef SectionVal;
 
   for (const auto &MFE : ModuleFlags) {
-    // Ignore flags with 'Require' behavior.
-    if (MFE.Behavior == Module::Require)
-      continue;
-
     StringRef Key = MFE.Key->getString();
-    Metadata *Val = MFE.Val;
-
-    if (Key == "Objective-C Image Info Version") {
-      VersionVal = mdconst::extract<ConstantInt>(Val)->getZExtValue();
-    } else if (Key == "Objective-C Garbage Collection" ||
-               Key == "Objective-C GC Only" ||
-               Key == "Objective-C Is Simulated" ||
-               Key == "Objective-C Class Properties" ||
-               Key == "Objective-C Image Swift Version") {
-      ImageInfoFlags |= mdconst::extract<ConstantInt>(Val)->getZExtValue();
-    } else if (Key == "Objective-C Image Info Section") {
-      SectionVal = cast<MDString>(Val)->getString();
-    } else if (Key == "Linker Options") {
-      LinkerOptions = cast<MDNode>(Val);
-    }
+    if (Key == "Linker Options")
+      LinkerOptions = cast<MDNode>(MFE.Val);
   }
 
   // Emit the linker options if present.
@@ -617,8 +640,14 @@ void TargetLoweringObjectFileMachO::emitModuleFlags(
     }
   }
 
+  unsigned VersionVal = 0;
+  unsigned ImageInfoFlags = 0;
+  StringRef SectionVal;
+  GetObjCImageInfo(ModuleFlags, VersionVal, ImageInfoFlags, SectionVal);
+
   // The section is mandatory. If we don't have it, then we don't have GC info.
-  if (SectionVal.empty()) return;
+  if (SectionVal.empty())
+    return;
 
   StringRef Segment, Section;
   unsigned TAA = 0, StubSize = 0;
@@ -1156,6 +1185,24 @@ void TargetLoweringObjectFileCOFF::emitModuleFlags(
       }
     }
   }
+
+  unsigned Version = 0;
+  unsigned Flags = 0;
+  StringRef Section;
+
+  GetObjCImageInfo(ModuleFlags, Version, Flags, Section);
+  if (Section.empty())
+    return;
+
+  auto &C = getContext();
+  auto *S = C.getCOFFSection(
+      Section, COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
+      SectionKind::getReadOnly());
+  Streamer.SwitchSection(S);
+  Streamer.EmitLabel(C.getOrCreateSymbol(StringRef("OBJC_IMAGE_INFO")));
+  Streamer.EmitIntValue(Version, 4);
+  Streamer.EmitIntValue(Flags, 4);
+  Streamer.AddBlankLine();
 }
 
 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
diff --git a/llvm/test/Object/objc-imageinfo-coff.ll b/llvm/test/Object/objc-imageinfo-coff.ll
new file mode 100644
index 0000000..cab0103
--- /dev/null
+++ b/llvm/test/Object/objc-imageinfo-coff.ll
@@ -0,0 +1,14 @@
+; RUN: llc -mtriple x86_64-unknown-windows-msvc -filetype asm -o - %s | FileCheck %s
+
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"Objective-C Version", i32 2}
+!1 = !{i32 1, !"Objective-C Image Info Version", i32 0}
+!2 = !{i32 1, !"Objective-C Image Info Section", !".objc_imageinfo$B"}
+!3 = !{i32 1, !"Objective-C Garbage Collection", i32 2}
+
+; CHECK: .section .objc_imageinfo$B,"dr"
+; CHECK: OBJC_IMAGE_INFO:
+; CHECK:   .long 0
+; CHECK:   .long 2
+
diff --git a/llvm/test/Object/objc-imageinfo-elf.ll b/llvm/test/Object/objc-imageinfo-elf.ll
new file mode 100644
index 0000000..7979e01
--- /dev/null
+++ b/llvm/test/Object/objc-imageinfo-elf.ll
@@ -0,0 +1,14 @@
+; RUN: llc -mtriple x86_64-unknown-linux-gnu -filetype asm -o - %s | FileCheck %s
+
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"Objective-C Version", i32 2}
+!1 = !{i32 1, !"Objective-C Image Info Version", i32 0}
+!2 = !{i32 1, !"Objective-C Image Info Section", !"objc_imageinfo"}
+!3 = !{i32 1, !"Objective-C Garbage Collection", i32 2}
+
+; CHECK: .section objc_imageinfo
+; CHECK: OBJC_IMAGE_INFO:
+; CHECK:   .long 0
+; CHECK:   .long 2
+
diff --git a/llvm/test/Object/objc-imageinfo-macho.ll b/llvm/test/Object/objc-imageinfo-macho.ll
new file mode 100644
index 0000000..90bc9d9
--- /dev/null
+++ b/llvm/test/Object/objc-imageinfo-macho.ll
@@ -0,0 +1,14 @@
+; RUN: llc -mtriple x86_64-apple-ios -filetype asm -o - %s | FileCheck %s
+
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = !{i32 1, !"Objective-C Version", i32 2}
+!1 = !{i32 1, !"Objective-C Image Info Version", i32 0}
+!2 = !{i32 1, !"Objective-C Image Info Section", !"__DATA,__objc_imageinfo,regular,no_dead_strip"}
+!3 = !{i32 1, !"Objective-C Garbage Collection", i32 2}
+
+; CHECK: .section __DATA,__objc_imageinfo,regular,no_dead_strip
+; CHECK: L_OBJC_IMAGE_INFO:
+; CHECK:   .long 0
+; CHECK:   .long 2
+