Make it easier to pass a custom diagnostic handler to the IR linker.

llvm-svn: 220732

llvm/include/llvm/Linker/Linker.h

@@ -12,8 +12,10 @@
 
 #include "llvm/ADT/SmallPtrSet.h"
 
-namespace llvm {
+#include <functional>
 
+namespace llvm {
+class DiagnosticInfo;
 class Module;
 class StructType;
 
@@ -28,6 +30,10 @@ class Linker {
       PreserveSource = 1 // Preserve the source module.
     };
 
+    typedef std::function<void(const DiagnosticInfo &)>
+        DiagnosticHandlerFunction;
+
+    Linker(Module *M, DiagnosticHandlerFunction DiagnosticHandler);
     Linker(Module *M);
     ~Linker();
 
@@ -44,11 +50,18 @@ class Linker {
       return linkInModule(Src, Linker::DestroySource);
     }
 
-    static bool LinkModules(Module *Dest, Module *Src, unsigned Mode);
+    static bool
+    LinkModules(Module *Dest, Module *Src, unsigned Mode,
+                DiagnosticHandlerFunction DiagnosticHandler);
+
+    static bool
+    LinkModules(Module *Dest, Module *Src, unsigned Mode);
+
 
   private:
     Module *Composite;
     SmallPtrSet<StructType*, 32> IdentifiedStructTypes;
+    DiagnosticHandlerFunction DiagnosticHandler;
 };
 
 } // End llvm namespace

llvm/lib/Linker/LinkModules.cpp

@@ -418,10 +418,14 @@ namespace {
     // Vector of functions to lazily link in.
     std::vector<Function*> LazilyLinkFunctions;
 
+    Linker::DiagnosticHandlerFunction DiagnosticHandler;
+
   public:
-    ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode)
+    ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode,
+                 Linker::DiagnosticHandlerFunction DiagnosticHandler)
         : DstM(dstM), SrcM(srcM), TypeMap(Set),
-          ValMaterializer(TypeMap, DstM, LazilyLinkFunctions), Mode(mode) {}
+          ValMaterializer(TypeMap, DstM, LazilyLinkFunctions), Mode(mode),
+          DiagnosticHandler(DiagnosticHandler) {}
 
     bool run();
 
@@ -431,12 +435,12 @@ namespace {
 
     /// Helper method for setting a message and returning an error code.
     bool emitError(const Twine &Message) {
-      DstM->getContext().diagnose(LinkDiagnosticInfo(DS_Error, Message));
+      DiagnosticHandler(LinkDiagnosticInfo(DS_Error, Message));
       return true;
     }
 
     void emitWarning(const Twine &Message) {
-      DstM->getContext().diagnose(LinkDiagnosticInfo(DS_Warning, Message));
+      DiagnosticHandler(LinkDiagnosticInfo(DS_Warning, Message));
     }
 
     bool getComdatLeader(Module *M, StringRef ComdatName,
@@ -1721,7 +1725,13 @@ bool ModuleLinker::run() {
   return false;
 }
 
-Linker::Linker(Module *M) : Composite(M) {
+Linker::Linker(Module *M, DiagnosticHandlerFunction DiagnosticHandler)
+    : Composite(M), DiagnosticHandler(DiagnosticHandler) {}
+
+Linker::Linker(Module *M)
+    : Composite(M), DiagnosticHandler([this](const DiagnosticInfo &DI) {
+                      Composite->getContext().diagnose(DI);
+                    }) {
   TypeFinder StructTypes;
   StructTypes.run(*M, true);
   IdentifiedStructTypes.insert(StructTypes.begin(), StructTypes.end());
@@ -1736,7 +1746,7 @@ void Linker::deleteModule() {
 }
 
 bool Linker::linkInModule(Module *Src, unsigned Mode) {
-  ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode);
+  ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode, DiagnosticHandler);
   return TheLinker.run();
 }
 
@@ -1749,6 +1759,12 @@ bool Linker::linkInModule(Module *Src, unsigned Mode) {
 /// true is returned and ErrorMsg (if not null) is set to indicate the problem.
 /// Upon failure, the Dest module could be in a modified state, and shouldn't be
 /// relied on to be consistent.
+bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode,
+                         DiagnosticHandlerFunction DiagnosticHandler) {
+  Linker L(Dest, DiagnosticHandler);
+  return L.linkInModule(Src, Mode);
+}
+
 bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode) {
   Linker L(Dest);
   return L.linkInModule(Src, Mode);
@@ -1758,31 +1774,15 @@ bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode) {
 // C API.
 //===----------------------------------------------------------------------===//
 
-static void bindingDiagnosticHandler(const llvm::DiagnosticInfo &DI,
-                                     void *Context) {
-  if (DI.getSeverity() != DS_Error)
-    return;
-
-  std::string *Message = (std::string *)Context;
-  {
-    raw_string_ostream Stream(*Message);
-    DiagnosticPrinterRawOStream DP(Stream);
-    DI.print(DP);
-  }
-}
-
-
 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
                          LLVMLinkerMode Mode, char **OutMessages) {
   Module *D = unwrap(Dest);
-  LLVMContext &Ctx = D->getContext();
-
-  LLVMContext::DiagnosticHandlerTy OldHandler = Ctx.getDiagnosticHandler();
-  void *OldDiagnosticContext = Ctx.getDiagnosticContext();
   std::string Message;
-  Ctx.setDiagnosticHandler(bindingDiagnosticHandler, &Message);
-  LLVMBool Result = Linker::LinkModules(D, unwrap(Src), Mode);
-  Ctx.setDiagnosticHandler(OldHandler, OldDiagnosticContext);
+  raw_string_ostream Stream(Message);
+  DiagnosticPrinterRawOStream DP(Stream);
+
+  LLVMBool Result = Linker::LinkModules(
+      D, unwrap(Src), Mode, [&](const DiagnosticInfo &DI) { DI.print(DP); });
 
   if (OutMessages && Result)
     *OutMessages = strdup(Message.c_str());

llvm/tools/llvm-link/llvm-link.cpp

@@ -71,11 +71,12 @@ loadFile(const char *argv0, const std::string &FN, LLVMContext &Context) {
   return Result;
 }
 
-static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
+static void diagnosticHandler(const DiagnosticInfo &DI) {
   unsigned Severity = DI.getSeverity();
   switch (Severity) {
   case DS_Error:
     errs() << "ERROR: ";
+    break;
   case DS_Warning:
     if (SuppressWarnings)
       return;
@@ -88,6 +89,7 @@ static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
 
   DiagnosticPrinterRawOStream DP(errs());
   DI.print(DP);
+  errs() << '\n';
 }
 
 int main(int argc, char **argv) {
@@ -100,9 +102,8 @@ int main(int argc, char **argv) {
   cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
 
   auto Composite = make_unique<Module>("llvm-link", Context);
-  Linker L(Composite.get());
+  Linker L(Composite.get(), diagnosticHandler);
 
-  Context.setDiagnosticHandler(diagnosticHandler);
   for (unsigned i = 0; i < InputFilenames.size(); ++i) {
     std::unique_ptr<Module> M = loadFile(argv[0], InputFilenames[i], Context);
     if (!M.get()) {