Assert on duplicate registration. Don't depend on function pointer equality.

Before this patch we would assert when building llvm as multiple shared
libraries (cmake's BUILD_SHARED_LIBS). The problem was the line

if (T.AsmStreamerCtorFn == Target::createDefaultAsmStreamer)

which returns false because of -fvisibility-inlines-hidden. It is easy
to fix just this one case, but I decided to try to also make the
registration more strict. It looks like the old logic for ignoring
followup registration was just a temporary hack that outlived its
usefulness.

This patch converts the ifs to asserts, fixes the few cases that were
registering twice and makes sure all the asserts compare with null.

Thanks for Joerg for reporting the problem and reviewing the patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192803 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 50 insertions, 62 deletions

diff --git a/include/llvm/Support/TargetRegistry.h b/include/llvm/Support/TargetRegistry.h
index 0bcb0ba691..6cca9e899b 100644
--- a/include/llvm/Support/TargetRegistry.h
+++ b/include/llvm/Support/TargetRegistry.h
@@ -235,22 +235,10 @@ namespace llvm {
     /// MCSymbolizer, if registered (default = llvm::createMCSymbolizer)
     MCSymbolizerCtorTy MCSymbolizerCtorFn;
 
-    static MCStreamer *
-    createDefaultAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
-                             bool isVerboseAsm, bool useLoc, bool useCFI,
-                             bool useDwarfDirectory, MCInstPrinter *InstPrint,
-                             MCCodeEmitter *CE, MCAsmBackend *TAB,
-                             bool ShowInst) {
-      return llvm::createAsmStreamer(Ctx, 0, OS, isVerboseAsm, useLoc, useCFI,
-                                     useDwarfDirectory, InstPrint, CE, TAB,
-                                     ShowInst);
-    }
-
   public:
     Target()
-        : AsmStreamerCtorFn(createDefaultAsmStreamer),
-          MCRelocationInfoCtorFn(llvm::createMCRelocationInfo),
-          MCSymbolizerCtorFn(llvm::createMCSymbolizer) {}
+        : AsmStreamerCtorFn(0), MCRelocationInfoCtorFn(0),
+          MCSymbolizerCtorFn(0) {}
 
     /// @name Target Information
     /// @{
@@ -452,9 +440,13 @@ namespace llvm {
                                   MCCodeEmitter *CE,
                                   MCAsmBackend *TAB,
                                   bool ShowInst) const {
-      // AsmStreamerCtorFn is default to llvm::createAsmStreamer
-      return AsmStreamerCtorFn(Ctx, OS, isVerboseAsm, useLoc, useCFI,
-                               useDwarfDirectory, InstPrint, CE, TAB, ShowInst);
+      if (AsmStreamerCtorFn)
+        return AsmStreamerCtorFn(Ctx, OS, isVerboseAsm, useLoc, useCFI,
+                                 useDwarfDirectory, InstPrint, CE, TAB,
+                                 ShowInst);
+      return llvm::createAsmStreamer(Ctx, 0, OS, isVerboseAsm, useLoc, useCFI,
+                                     useDwarfDirectory, InstPrint, CE, TAB,
+                                     ShowInst);
     }
 
     /// createMCRelocationInfo - Create a target specific MCRelocationInfo.
@@ -463,7 +455,10 @@ namespace llvm {
     /// \param Ctx The target context.
     MCRelocationInfo *
       createMCRelocationInfo(StringRef TT, MCContext &Ctx) const {
-      return MCRelocationInfoCtorFn(TT, Ctx);
+      MCRelocationInfoCtorTy Fn = MCRelocationInfoCtorFn
+                                      ? MCRelocationInfoCtorFn
+                                      : llvm::createMCRelocationInfo;
+      return Fn(TT, Ctx);
     }
 
     /// createMCSymbolizer - Create a target specific MCSymbolizer.
@@ -480,8 +475,9 @@ namespace llvm {
                        LLVMSymbolLookupCallback SymbolLookUp,
                        void *DisInfo,
                        MCContext *Ctx, MCRelocationInfo *RelInfo) const {
-      return MCSymbolizerCtorFn(TT, GetOpInfo, SymbolLookUp, DisInfo,
-                                Ctx, RelInfo);
+      MCSymbolizerCtorTy Fn =
+          MCSymbolizerCtorFn ? MCSymbolizerCtorFn : llvm::createMCSymbolizer;
+      return Fn(TT, GetOpInfo, SymbolLookUp, DisInfo, Ctx, RelInfo);
     }
 
     /// @}
@@ -602,9 +598,8 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct a MCAsmInfo for the target.
     static void RegisterMCAsmInfo(Target &T, Target::MCAsmInfoCtorFnTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.MCAsmInfoCtorFn)
-        T.MCAsmInfoCtorFn = Fn;
+      assert(!T.MCAsmInfoCtorFn);
+      T.MCAsmInfoCtorFn = Fn;
     }
 
     /// RegisterMCCodeGenInfo - Register a MCCodeGenInfo implementation for the
@@ -618,9 +613,8 @@ namespace llvm {
     /// @param Fn - A function to construct a MCCodeGenInfo for the target.
     static void RegisterMCCodeGenInfo(Target &T,
                                      Target::MCCodeGenInfoCtorFnTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.MCCodeGenInfoCtorFn)
-        T.MCCodeGenInfoCtorFn = Fn;
+      assert(!T.MCCodeGenInfoCtorFn);
+      T.MCCodeGenInfoCtorFn = Fn;
     }
 
     /// RegisterMCInstrInfo - Register a MCInstrInfo implementation for the
@@ -633,18 +627,16 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct a MCInstrInfo for the target.
     static void RegisterMCInstrInfo(Target &T, Target::MCInstrInfoCtorFnTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.MCInstrInfoCtorFn)
-        T.MCInstrInfoCtorFn = Fn;
+      assert(!T.MCInstrInfoCtorFn);
+      T.MCInstrInfoCtorFn = Fn;
     }
 
     /// RegisterMCInstrAnalysis - Register a MCInstrAnalysis implementation for
     /// the given target.
     static void RegisterMCInstrAnalysis(Target &T,
                                         Target::MCInstrAnalysisCtorFnTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.MCInstrAnalysisCtorFn)
-        T.MCInstrAnalysisCtorFn = Fn;
+      assert(!T.MCInstrAnalysisCtorFn);
+      T.MCInstrAnalysisCtorFn = Fn;
     }
 
     /// RegisterMCRegInfo - Register a MCRegisterInfo implementation for the
@@ -657,9 +649,8 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct a MCRegisterInfo for the target.
     static void RegisterMCRegInfo(Target &T, Target::MCRegInfoCtorFnTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.MCRegInfoCtorFn)
-        T.MCRegInfoCtorFn = Fn;
+      assert(!T.MCRegInfoCtorFn);
+      T.MCRegInfoCtorFn = Fn;
     }
 
     /// RegisterMCSubtargetInfo - Register a MCSubtargetInfo implementation for
@@ -673,9 +664,8 @@ namespace llvm {
     /// @param Fn - A function to construct a MCSubtargetInfo for the target.
     static void RegisterMCSubtargetInfo(Target &T,
                                         Target::MCSubtargetInfoCtorFnTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.MCSubtargetInfoCtorFn)
-        T.MCSubtargetInfoCtorFn = Fn;
+      assert(!T.MCSubtargetInfoCtorFn);
+      T.MCSubtargetInfoCtorFn = Fn;
     }
 
     /// RegisterTargetMachine - Register a TargetMachine implementation for the
@@ -689,9 +679,8 @@ namespace llvm {
     /// @param Fn - A function to construct a TargetMachine for the target.
     static void RegisterTargetMachine(Target &T,
                                       Target::TargetMachineCtorTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.TargetMachineCtorFn)
-        T.TargetMachineCtorFn = Fn;
+      assert(!T.TargetMachineCtorFn);
+      T.TargetMachineCtorFn = Fn;
     }
 
     /// RegisterMCAsmBackend - Register a MCAsmBackend implementation for the
@@ -704,8 +693,8 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct an AsmBackend for the target.
     static void RegisterMCAsmBackend(Target &T, Target::MCAsmBackendCtorTy Fn) {
-      if (!T.MCAsmBackendCtorFn)
-        T.MCAsmBackendCtorFn = Fn;
+      assert(!T.MCAsmBackendCtorFn);
+      T.MCAsmBackendCtorFn = Fn;
     }
 
     /// RegisterMCAsmParser - Register a MCTargetAsmParser implementation for
@@ -718,8 +707,8 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct an MCTargetAsmParser for the target.
     static void RegisterMCAsmParser(Target &T, Target::MCAsmParserCtorTy Fn) {
-      if (!T.MCAsmParserCtorFn)
-        T.MCAsmParserCtorFn = Fn;
+      assert(!T.MCAsmParserCtorFn);
+      T.MCAsmParserCtorFn = Fn;
     }
 
     /// RegisterAsmPrinter - Register an AsmPrinter implementation for the given
@@ -732,9 +721,8 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct an AsmPrinter for the target.
     static void RegisterAsmPrinter(Target &T, Target::AsmPrinterCtorTy Fn) {
-      // Ignore duplicate registration.
-      if (!T.AsmPrinterCtorFn)
-        T.AsmPrinterCtorFn = Fn;
+      assert(!T.AsmPrinterCtorFn);
+      T.AsmPrinterCtorFn = Fn;
     }
 
     /// RegisterMCDisassembler - Register a MCDisassembler implementation for
@@ -748,8 +736,8 @@ namespace llvm {
     /// @param Fn - A function to construct an MCDisassembler for the target.
     static void RegisterMCDisassembler(Target &T,
                                        Target::MCDisassemblerCtorTy Fn) {
-      if (!T.MCDisassemblerCtorFn)
-        T.MCDisassemblerCtorFn = Fn;
+      assert(!T.MCDisassemblerCtorFn);
+      T.MCDisassemblerCtorFn = Fn;
     }
 
     /// RegisterMCInstPrinter - Register a MCInstPrinter implementation for the
@@ -763,8 +751,8 @@ namespace llvm {
     /// @param Fn - A function to construct an MCInstPrinter for the target.
     static void RegisterMCInstPrinter(Target &T,
                                       Target::MCInstPrinterCtorTy Fn) {
-      if (!T.MCInstPrinterCtorFn)
-        T.MCInstPrinterCtorFn = Fn;
+      assert(!T.MCInstPrinterCtorFn);
+      T.MCInstPrinterCtorFn = Fn;
     }
 
     /// RegisterMCCodeEmitter - Register a MCCodeEmitter implementation for the
@@ -778,8 +766,8 @@ namespace llvm {
     /// @param Fn - A function to construct an MCCodeEmitter for the target.
     static void RegisterMCCodeEmitter(Target &T,
                                       Target::MCCodeEmitterCtorTy Fn) {
-      if (!T.MCCodeEmitterCtorFn)
-        T.MCCodeEmitterCtorFn = Fn;
+      assert(!T.MCCodeEmitterCtorFn);
+      T.MCCodeEmitterCtorFn = Fn;
     }
 
     /// RegisterMCObjectStreamer - Register a object code MCStreamer
@@ -793,8 +781,8 @@ namespace llvm {
     /// @param Fn - A function to construct an MCStreamer for the target.
     static void RegisterMCObjectStreamer(Target &T,
                                          Target::MCObjectStreamerCtorTy Fn) {
-      if (!T.MCObjectStreamerCtorFn)
-        T.MCObjectStreamerCtorFn = Fn;
+      assert(!T.MCObjectStreamerCtorFn);
+      T.MCObjectStreamerCtorFn = Fn;
     }
 
     /// RegisterAsmStreamer - Register an assembly MCStreamer implementation
@@ -807,8 +795,8 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct an MCStreamer for the target.
     static void RegisterAsmStreamer(Target &T, Target::AsmStreamerCtorTy Fn) {
-      if (T.AsmStreamerCtorFn == Target::createDefaultAsmStreamer)
-        T.AsmStreamerCtorFn = Fn;
+      assert(!T.AsmStreamerCtorFn);
+      T.AsmStreamerCtorFn = Fn;
     }
 
     /// RegisterMCRelocationInfo - Register an MCRelocationInfo
@@ -822,8 +810,8 @@ namespace llvm {
     /// @param Fn - A function to construct an MCRelocationInfo for the target.
     static void RegisterMCRelocationInfo(Target &T,
                                          Target::MCRelocationInfoCtorTy Fn) {
-      if (T.MCRelocationInfoCtorFn == llvm::createMCRelocationInfo)
-        T.MCRelocationInfoCtorFn = Fn;
+      assert(!T.MCRelocationInfoCtorFn);
+      T.MCRelocationInfoCtorFn = Fn;
     }
 
     /// RegisterMCSymbolizer - Register an MCSymbolizer
@@ -837,8 +825,8 @@ namespace llvm {
     /// @param Fn - A function to construct an MCSymbolizer for the target.
     static void RegisterMCSymbolizer(Target &T,
                                      Target::MCSymbolizerCtorTy Fn) {
-      if (T.MCSymbolizerCtorFn == llvm::createMCSymbolizer)
-        T.MCSymbolizerCtorFn = Fn;
+      assert(!T.MCSymbolizerCtorFn);
+      T.MCSymbolizerCtorFn = Fn;
     }
 
     /// @}