[LTO] Fix error reporting from lto_module_create_in_local_context()

Function lto_module_create_in_local_context() would previously
rely on the default LLVMContext being created for it by
LTOModule::makeLTOModule(). This context exits the program on
error and is not arranged to update sLastStringError in
tools/lto/lto.cpp.

Function lto_module_create_in_local_context() now creates an
LLVMContext by itself, sets it up correctly to its needs and then
passes it to LTOModule::createInLocalContext() which takes
ownership of the context and keeps it present for the lifetime of
the returned LTOModule.

Function LTOModule::makeLTOModule() is modified to take a
reference to LLVMContext (instead of a pointer) and no longer
creates a default context when nullptr is passed to it. Method
LTOModule::createInContext() that takes a pointer to LLVMContext
is removed because it allows to pass a nullptr to it. Instead
LTOModule::createFromBuffer() (that takes a reference to
LLVMContext) should be used.

Differential Revision: http://reviews.llvm.org/D17715

llvm-svn: 262330

llvm/include/llvm/LTO/LTOModule.h

@@ -57,8 +57,6 @@ struct LTOModule {
   std::vector<const char*>                _asm_undefines;
 
   LTOModule(std::unique_ptr<object::IRObjectFile> Obj, TargetMachine *TM);
-  LTOModule(std::unique_ptr<object::IRObjectFile> Obj, TargetMachine *TM,
-            std::unique_ptr<LLVMContext> Context);
 
 public:
   ~LTOModule();
@@ -100,13 +98,9 @@ struct LTOModule {
   static ErrorOr<std::unique_ptr<LTOModule>>
   createFromBuffer(LLVMContext &Context, const void *mem, size_t length,
                    TargetOptions options, StringRef path = "");
-
-  static ErrorOr<std::unique_ptr<LTOModule>>
-  createInLocalContext(const void *mem, size_t length, TargetOptions options,
-                       StringRef path);
   static ErrorOr<std::unique_ptr<LTOModule>>
-  createInContext(const void *mem, size_t length, TargetOptions options,
-                  StringRef path, LLVMContext *Context);
+  createInLocalContext(std::unique_ptr<LLVMContext> Context, const void *mem,
+                       size_t length, TargetOptions options, StringRef path);
 
   const Module &getModule() const {
     return const_cast<LTOModule*>(this)->getModule();
@@ -206,7 +200,7 @@ struct LTOModule {
   /// Create an LTOModule (private version).
   static ErrorOr<std::unique_ptr<LTOModule>>
   makeLTOModule(MemoryBufferRef Buffer, TargetOptions options,
-                LLVMContext *Context);
+                LLVMContext &Context, bool ShouldBeLazy);
 };
 }
 #endif

llvm/lib/LTO/LTOModule.cpp

@@ -54,11 +54,6 @@ LTOModule::LTOModule(std::unique_ptr<object::IRObjectFile> Obj,
                      llvm::TargetMachine *TM)
     : IRFile(std::move(Obj)), _target(TM) {}
 
-LTOModule::LTOModule(std::unique_ptr<object::IRObjectFile> Obj,
-                     llvm::TargetMachine *TM,
-                     std::unique_ptr<LLVMContext> Context)
-    : OwnedContext(std::move(Context)), IRFile(std::move(Obj)), _target(TM) {}
-
 LTOModule::~LTOModule() {}
 
 /// isBitcodeFile - Returns 'true' if the file (or memory contents) is LLVM
@@ -110,7 +105,8 @@ LTOModule::createFromFile(LLVMContext &Context, const char *path,
     return EC;
   }
   std::unique_ptr<MemoryBuffer> Buffer = std::move(BufferOrErr.get());
-  return makeLTOModule(Buffer->getMemBufferRef(), options, &Context);
+  return makeLTOModule(Buffer->getMemBufferRef(), options, Context,
+                       /* ShouldBeLazy*/ false);
 }
 
 ErrorOr<std::unique_ptr<LTOModule>>
@@ -130,29 +126,32 @@ LTOModule::createFromOpenFileSlice(LLVMContext &Context, int fd,
     return EC;
   }
   std::unique_ptr<MemoryBuffer> Buffer = std::move(BufferOrErr.get());
-  return makeLTOModule(Buffer->getMemBufferRef(), options, &Context);
+  return makeLTOModule(Buffer->getMemBufferRef(), options, Context,
+                       /* ShouldBeLazy */ false);
 }
 
 ErrorOr<std::unique_ptr<LTOModule>>
 LTOModule::createFromBuffer(LLVMContext &Context, const void *mem,
                             size_t length, TargetOptions options,
                             StringRef path) {
-  return createInContext(mem, length, options, path, &Context);
+  StringRef Data((const char *)mem, length);
+  MemoryBufferRef Buffer(Data, path);
+  return makeLTOModule(Buffer, options, Context, /* ShouldBeLazy */ false);
 }
 
 ErrorOr<std::unique_ptr<LTOModule>>
-LTOModule::createInLocalContext(const void *mem, size_t length,
+LTOModule::createInLocalContext(std::unique_ptr<LLVMContext> Context,
+                                const void *mem, size_t length,
                                 TargetOptions options, StringRef path) {
-  return createInContext(mem, length, options, path, nullptr);
-}
-
-ErrorOr<std::unique_ptr<LTOModule>>
-LTOModule::createInContext(const void *mem, size_t length,
-                           TargetOptions options, StringRef path,
-                           LLVMContext *Context) {
   StringRef Data((const char *)mem, length);
   MemoryBufferRef Buffer(Data, path);
-  return makeLTOModule(Buffer, options, Context);
+  // If we own a context, we know this is being used only for symbol extraction,
+  // not linking.  Be lazy in that case.
+  ErrorOr<std::unique_ptr<LTOModule>> Ret =
+      makeLTOModule(Buffer, options, *Context, /* ShouldBeLazy */ true);
+  if (Ret)
+    (*Ret)->OwnedContext = std::move(Context);
+  return std::move(Ret);
 }
 
 static ErrorOr<std::unique_ptr<Module>>
@@ -187,18 +186,9 @@ parseBitcodeFileImpl(MemoryBufferRef Buffer, LLVMContext &Context,
 
 ErrorOr<std::unique_ptr<LTOModule>>
 LTOModule::makeLTOModule(MemoryBufferRef Buffer, TargetOptions options,
-                         LLVMContext *Context) {
-  std::unique_ptr<LLVMContext> OwnedContext;
-  if (!Context) {
-    OwnedContext = llvm::make_unique<LLVMContext>();
-    Context = OwnedContext.get();
-  }
-
-  // If we own a context, we know this is being used only for symbol
-  // extraction, not linking.  Be lazy in that case.
+                         LLVMContext &Context, bool ShouldBeLazy) {
   ErrorOr<std::unique_ptr<Module>> MOrErr =
-      parseBitcodeFileImpl(Buffer, *Context,
-                           /* ShouldBeLazy */ static_cast<bool>(OwnedContext));
+      parseBitcodeFileImpl(Buffer, Context, ShouldBeLazy);
   if (std::error_code EC = MOrErr.getError())
     return EC;
   std::unique_ptr<Module> &M = *MOrErr;
@@ -236,12 +226,7 @@ LTOModule::makeLTOModule(MemoryBufferRef Buffer, TargetOptions options,
   std::unique_ptr<object::IRObjectFile> IRObj(
       new object::IRObjectFile(Buffer, std::move(M)));
 
-  std::unique_ptr<LTOModule> Ret;
-  if (OwnedContext)
-    Ret.reset(new LTOModule(std::move(IRObj), target, std::move(OwnedContext)));
-  else
-    Ret.reset(new LTOModule(std::move(IRObj), target));
-
+  std::unique_ptr<LTOModule> Ret(new LTOModule(std::move(IRObj), target));
   Ret->parseSymbols();
   Ret->parseMetadata();
 

llvm/test/tools/llvm-lto/error.ll

@@ -1,2 +1,5 @@
 ; RUN: not llvm-lto foobar 2>&1 | FileCheck %s
 ; CHECK: llvm-lto: error loading file 'foobar': {{N|n}}o such file or directory
+
+; RUN: not llvm-lto --list-symbols-only %S/Inputs/empty.bc 2>&1 | FileCheck %s --check-prefix=CHECK-LIST
+; CHECK-LIST: llvm-lto: error loading file '{{.*}}/Inputs/empty.bc': The file was not recognized as a valid object file

llvm/tools/llvm-lto/llvm-lto.cpp

@@ -158,8 +158,8 @@ static void diagnosticHandler(const DiagnosticInfo &DI) {
     exit(1);
 }
 
-static void diagnosticHandlerWithContenxt(const DiagnosticInfo &DI,
-                                          void *Context) {
+static void diagnosticHandlerWithContext(const DiagnosticInfo &DI,
+                                         void *Context) {
   diagnosticHandler(DI);
 }
 
@@ -186,8 +186,11 @@ getLocalLTOModule(StringRef Path, std::unique_ptr<MemoryBuffer> &Buffer,
   error(BufferOrErr, "error loading file '" + Path + "'");
   Buffer = std::move(BufferOrErr.get());
   CurrentActivity = ("loading file '" + Path + "'").str();
+  std::unique_ptr<LLVMContext> Context = llvm::make_unique<LLVMContext>();
+  Context->setDiagnosticHandler(diagnosticHandlerWithContext, nullptr, true);
   ErrorOr<std::unique_ptr<LTOModule>> Ret = LTOModule::createInLocalContext(
-      Buffer->getBufferStart(), Buffer->getBufferSize(), Options, Path);
+      std::move(Context), Buffer->getBufferStart(), Buffer->getBufferSize(),
+      Options, Path);
   CurrentActivity = "";
   return std::move(*Ret);
 }
@@ -271,7 +274,7 @@ int main(int argc, char **argv) {
   unsigned BaseArg = 0;
 
   LLVMContext Context;
-  Context.setDiagnosticHandler(diagnosticHandlerWithContenxt, nullptr, true);
+  Context.setDiagnosticHandler(diagnosticHandlerWithContext, nullptr, true);
 
   LTOCodeGenerator CodeGen(Context);
 

llvm/tools/lto/lto.cpp

@@ -248,8 +248,14 @@ lto_module_t lto_module_create_in_local_context(const void *mem, size_t length,
                                                 const char *path) {
   lto_initialize();
   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
+
+  // Create a local context. Ownership will be transfered to LTOModule.
+  std::unique_ptr<LLVMContext> Context = llvm::make_unique<LLVMContext>();
+  Context->setDiagnosticHandler(diagnosticHandler, nullptr, true);
+
   ErrorOr<std::unique_ptr<LTOModule>> M =
-      LTOModule::createInLocalContext(mem, length, Options, path);
+      LTOModule::createInLocalContext(std::move(Context), mem, length, Options,
+                                      path);
   if (!M)
     return nullptr;
   return wrap(M->release());
@@ -261,8 +267,8 @@ lto_module_t lto_module_create_in_codegen_context(const void *mem,
                                                   lto_code_gen_t cg) {
   lto_initialize();
   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
-  ErrorOr<std::unique_ptr<LTOModule>> M = LTOModule::createInContext(
-      mem, length, Options, path, &unwrap(cg)->getContext());
+  ErrorOr<std::unique_ptr<LTOModule>> M = LTOModule::createFromBuffer(
+      unwrap(cg)->getContext(), mem, length, Options, path);
   return wrap(M->release());
 }