[StreamExecutor] Add KernelLoaderSpec

Summary:
Add definitions for the KernelLoaderSpec and MultiKernelLoaderSpec
classes to StreamExecutor. Instances of these classes are generated by the
compiler in order to provide host code with a handle to device code.

Reviewers: jlebar, tra

Subscribers: parallel_libs-commits

Differential Revision: https://reviews.llvm.org/D23038

6 files changed, 508 insertions, 0 deletions

diff --git a/parallel-libs/streamexecutor/CMakeLists.txt b/parallel-libs/streamexecutor/CMakeLists.txt
index 2cf7cee34d9..18c28d62fef 100644
--- a/parallel-libs/streamexecutor/CMakeLists.txt
+++ b/parallel-libs/streamexecutor/CMakeLists.txt
@@ -32,6 +32,7 @@ if(STREAM_EXECUTOR_STANDALONE)
         enable_testing()
         find_package(GTest REQUIRED)
         include_directories(${GTEST_INCLUDE_DIRS})
+        find_package(Threads REQUIRED)
     endif()
 else(NOT STREAM_EXECUTOR_STANDALONE)
     if(STREAM_EXECUTOR_UNIT_TESTS)
diff --git a/parallel-libs/streamexecutor/include/streamexecutor/KernelSpec.h b/parallel-libs/streamexecutor/include/streamexecutor/KernelSpec.h
new file mode 100644
index 00000000000..a6943143086
--- /dev/null
+++ b/parallel-libs/streamexecutor/include/streamexecutor/KernelSpec.h
@@ -0,0 +1,263 @@
+//===-- KernelSpec.h - Kernel loader spec types -----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// KernelLoaderSpec is the base class for types that know where to find the
+/// code for a data-parallel kernel in a particular format on a particular
+/// platform. So, for example, there will be one subclass that deals with CUDA
+/// PTX code, another subclass that deals with CUDA fatbin code, and yet another
+/// subclass that deals with OpenCL text code.
+///
+/// A MultiKernelLoaderSpec is basically a collection of KernelLoaderSpec
+/// instances. This is useful when code is available for the same kernel in
+/// several different formats or targeted for several different platforms. All
+/// the various KernelLoaderSpec instances for this kernel can be combined
+/// together in one MultiKernelLoaderSpec and the specific platform consumer can
+/// decide which instance of the code it wants to use.
+///
+/// MultiKernelLoaderSpec provides several helper functions to build and
+/// register KernelLoaderSpec instances all in a single operation. For example,
+/// MultiKernelLoaderSpec::addCUDAPTXInMemory can be used to construct and
+/// register a CUDAPTXInMemorySpec KernelLoaderSpec.
+///
+/// The loader spec classes declared here are designed primarily to be
+/// instantiated by the compiler, but they can also be instantiated directly by
+/// the user. A simplified example workflow which a compiler might follow in the
+/// case of a CUDA kernel that is compiled to CUDA fatbin code is as follows:
+///
+/// 1. The user defines a kernel function called UserKernel.
+/// 2. The compiler compiles the kernel code into CUDA fatbin data and embeds
+///    that data into the host code at address __UserKernelFatbinAddress.
+/// 3. The compiler adds code at the beginning of the host code to instantiate a
+///    MultiKernelLoaderSpec:
+///    \code
+///    namespace compiler_cuda_namespace {
+///      MultiKernelLoaderSpec UserKernelLoaderSpec;
+///    } // namespace compiler_cuda_namespace
+///    \endcode
+/// 4. The compiler then adds code to the host code to add the fatbin data to
+///    the new MultiKernelLoaderSpec, and to associate that data with the kernel
+///    name "UserKernel":
+///    \code
+///    namespace compiler_cuda_namespace {
+///      UserKernelLoaderSpec.addCUDAFatbinInMemory(
+///        __UserKernelFatbinAddress, "UserKernel");
+///    } // namespace compiler_cuda_namespace
+///    \encode
+/// 5. The host code, having known beforehand that the compiler would initialize
+///    a MultiKernelLoaderSpec based on the name of the CUDA kernel, makes use
+///    of the symbol cudanamespace::UserKernelLoaderSpec without defining it.
+///
+/// In the example above, the MultiKernelLoaderSpec instance created by the
+/// compiler can be used by the host code to create StreamExecutor kernel
+/// objects. In turn, those StreamExecutor kernel objects can be used by the
+/// host code to launch the kernel on the device as desired.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef STREAMEXECUTOR_KERNELSPEC_H
+#define STREAMEXECUTOR_KERNELSPEC_H
+
+#include <cassert>
+#include <map>
+#include <memory>
+#include <string>
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+
+namespace streamexecutor {
+
+/// An object that knows how to find the code for a device kernel.
+///
+/// This is the base class for the hierarchy of loader specs. The different
+/// subclasses know how to find code in different formats (e.g. CUDA PTX, OpenCL
+/// binary).
+///
+/// This base class has functionality for storing and getting the name of the
+/// kernel as a string.
+class KernelLoaderSpec {
+public:
+  /// Returns the name of the kernel this spec loads.
+  const std::string &getKernelName() const { return KernelName; }
+
+protected:
+  explicit KernelLoaderSpec(llvm::StringRef KernelName);
+
+private:
+  std::string KernelName;
+
+  KernelLoaderSpec(const KernelLoaderSpec &) = delete;
+  KernelLoaderSpec &operator=(const KernelLoaderSpec &) = delete;
+};
+
+/// A KernelLoaderSpec for CUDA PTX code that resides in memory as a
+/// null-terminated string.
+class CUDAPTXInMemorySpec : public KernelLoaderSpec {
+public:
+  /// First component is major version, second component is minor version.
+  using ComputeCapability = std::pair<int, int>;
+
+  /// PTX code combined with its compute capability.
+  struct PTXSpec {
+    ComputeCapability TheComputeCapability;
+    const char *PTXCode;
+  };
+
+  /// Creates a CUDAPTXInMemorySpec from an array of PTXSpec objects.
+  ///
+  /// Adds each item in SpecList to this object.
+  ///
+  /// Does not take ownership of the PTXCode pointers in the SpecList elements.
+  CUDAPTXInMemorySpec(llvm::StringRef KernelName,
+                      const llvm::ArrayRef<PTXSpec> SpecList);
+
+  /// Returns a pointer to the PTX code for the requested compute capability.
+  ///
+  /// Returns nullptr on failed lookup (if the requested compute capability is
+  /// not available). Matches exactly the specified compute capability. Doesn't
+  /// try to do anything smart like finding the next best compute capability if
+  /// the specified capability cannot be found.
+  const char *getCode(int ComputeCapabilityMajor,
+                      int ComputeCapabilityMinor) const;
+
+private:
+  /// PTX code contents in memory.
+  ///
+  /// The key is a pair (cc_major, cc_minor), i.e., (2, 0), (3, 0), (3, 5).
+  std::map<ComputeCapability, const char *> PTXByComputeCapability;
+
+  CUDAPTXInMemorySpec(const CUDAPTXInMemorySpec &) = delete;
+  CUDAPTXInMemorySpec &operator=(const CUDAPTXInMemorySpec &) = delete;
+};
+
+/// A KernelLoaderSpec for CUDA fatbin code that resides in memory.
+class CUDAFatbinInMemorySpec : public KernelLoaderSpec {
+public:
+  /// Creates a CUDAFatbinInMemorySpec with a reference to the given fatbin
+  /// bytes.
+  ///
+  /// Does not take ownership of the Bytes pointer.
+  CUDAFatbinInMemorySpec(llvm::StringRef KernelName, const void *Bytes);
+
+  /// Gets the fatbin data bytes.
+  const void *getBytes() const { return Bytes; }
+
+private:
+  const void *Bytes;
+
+  CUDAFatbinInMemorySpec(const CUDAFatbinInMemorySpec &) = delete;
+  CUDAFatbinInMemorySpec &operator=(const CUDAFatbinInMemorySpec &) = delete;
+};
+
+/// A KernelLoaderSpec for OpenCL text that resides in memory as a
+/// null-terminated string.
+class OpenCLTextInMemorySpec : public KernelLoaderSpec {
+public:
+  /// Creates a OpenCLTextInMemorySpec with a reference to the given OpenCL text
+  /// code bytes.
+  ///
+  /// Does not take ownership of the Text pointer.
+  OpenCLTextInMemorySpec(llvm::StringRef KernelName, const char *Text);
+
+  /// Returns the OpenCL text contents.
+  const char *getText() const { return Text; }
+
+private:
+  const char *Text;
+
+  OpenCLTextInMemorySpec(const OpenCLTextInMemorySpec &) = delete;
+  OpenCLTextInMemorySpec &operator=(const OpenCLTextInMemorySpec &) = delete;
+};
+
+/// An object to store several different KernelLoaderSpecs for the same kernel.
+///
+/// This allows code in different formats and for different platforms to be
+/// stored all together for a single kernel.
+///
+/// Various methods are available to add a new KernelLoaderSpec to a
+/// MultiKernelLoaderSpec. There are also methods to query which formats and
+/// platforms are supported by the currently added KernelLoaderSpec objects, and
+/// methods to get the KernelLoaderSpec objects for each format and platform.
+///
+/// Since all stored KernelLoaderSpecs are supposed to reference the same
+/// kernel, they are all assumed to take the same number and type of parameters,
+/// but no checking is done to enforce this. In debug mode, all
+/// KernelLoaderSpecs are checked to make sure they have the same kernel name,
+/// so passing in specs with different kernel names can cause the program to
+/// abort.
+///
+/// This interface is prone to errors, so it is better to leave
+/// MultiKernelLoaderSpec creation and initialization to the compiler rather
+/// than doing it by hand.
+class MultiKernelLoaderSpec {
+public:
+  // Convenience getters for testing whether these platform variants have
+  // kernel loader specifications available.
+
+  bool hasCUDAPTXInMemory() const { return TheCUDAPTXInMemorySpec != nullptr; }
+  bool hasCUDAFatbinInMemory() const {
+    return TheCUDAFatbinInMemorySpec != nullptr;
+  }
+  bool hasOpenCLTextInMemory() const {
+    return TheOpenCLTextInMemorySpec != nullptr;
+  }
+
+  // Accessors for platform variant kernel load specifications.
+  //
+  // Precondition: corresponding has* method returns true.
+
+  const CUDAPTXInMemorySpec &getCUDAPTXInMemory() const {
+    assert(hasCUDAPTXInMemory() && "getting spec that is not present");
+    return *TheCUDAPTXInMemorySpec;
+  }
+  const CUDAFatbinInMemorySpec &getCUDAFatbinInMemory() const {
+    assert(hasCUDAFatbinInMemory() && "getting spec that is not present");
+    return *TheCUDAFatbinInMemorySpec;
+  }
+  const OpenCLTextInMemorySpec &getOpenCLTextInMemory() const {
+    assert(hasOpenCLTextInMemory() && "getting spec that is not present");
+    return *TheOpenCLTextInMemorySpec;
+  }
+
+  // Builder-pattern-like methods for use in initializing a
+  // MultiKernelLoaderSpec.
+  //
+  // Each of these should be used at most once for a single
+  // MultiKernelLoaderSpec object. See file comment for example usage.
+  //
+  // Note that the KernelName parameter must be consistent with the kernel in
+  // the PTX or OpenCL being loaded. Also be aware that in CUDA C++ the kernel
+  // name may be mangled by the compiler if it is not declared extern "C".
+
+  /// Does not take ownership of the PTXCode pointers in the SpecList elements.
+  MultiKernelLoaderSpec &
+  addCUDAPTXInMemory(llvm::StringRef KernelName,
+                     llvm::ArrayRef<CUDAPTXInMemorySpec::PTXSpec> SpecList);
+
+  /// Does not take ownership of the FatbinBytes pointer.
+  MultiKernelLoaderSpec &addCUDAFatbinInMemory(llvm::StringRef KernelName,
+                                               const void *FatbinBytes);
+
+  /// Does not take ownership of the OpenCLText pointer.
+  MultiKernelLoaderSpec &addOpenCLTextInMemory(llvm::StringRef KernelName,
+                                               const char *OpenCLText);
+
+private:
+  void setKernelName(llvm::StringRef KernelName);
+
+  std::unique_ptr<std::string> TheKernelName;
+  std::unique_ptr<CUDAPTXInMemorySpec> TheCUDAPTXInMemorySpec;
+  std::unique_ptr<CUDAFatbinInMemorySpec> TheCUDAFatbinInMemorySpec;
+  std::unique_ptr<OpenCLTextInMemorySpec> TheOpenCLTextInMemorySpec;
+};
+
+} // namespace streamexecutor
+
+#endif // STREAMEXECUTOR_KERNELSPEC_H
diff --git a/parallel-libs/streamexecutor/lib/CMakeLists.txt b/parallel-libs/streamexecutor/lib/CMakeLists.txt
index 5b3fe92d4b4..f8f0c163988 100644
--- a/parallel-libs/streamexecutor/lib/CMakeLists.txt
+++ b/parallel-libs/streamexecutor/lib/CMakeLists.txt
@@ -2,3 +2,12 @@ add_library(
     utils
     OBJECT
     Utils/Error.cpp)
+
+add_library(
+    streamexecutor
+    $<TARGET_OBJECTS:utils>
+    KernelSpec.cpp)
+
+if(STREAM_EXECUTOR_UNIT_TESTS)
+    add_subdirectory(unittests)
+endif()
diff --git a/parallel-libs/streamexecutor/lib/KernelSpec.cpp b/parallel-libs/streamexecutor/lib/KernelSpec.cpp
new file mode 100644
index 00000000000..d2715aa88a5
--- /dev/null
+++ b/parallel-libs/streamexecutor/lib/KernelSpec.cpp
@@ -0,0 +1,94 @@
+//===-- KernelSpec.cpp - General kernel spec implementation ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the implementation details for kernel loader specs.
+///
+//===----------------------------------------------------------------------===//
+
+#include "streamexecutor/KernelSpec.h"
+
+#include "llvm/ADT/STLExtras.h"
+
+namespace streamexecutor {
+
+KernelLoaderSpec::KernelLoaderSpec(llvm::StringRef KernelName)
+    : KernelName(KernelName) {}
+
+CUDAPTXInMemorySpec::CUDAPTXInMemorySpec(
+    llvm::StringRef KernelName,
+    const llvm::ArrayRef<CUDAPTXInMemorySpec::PTXSpec> SpecList)
+    : KernelLoaderSpec(KernelName) {
+  for (const auto &Spec : SpecList) {
+    PTXByComputeCapability.emplace(Spec.TheComputeCapability, Spec.PTXCode);
+  }
+}
+
+const char *CUDAPTXInMemorySpec::getCode(int ComputeCapabilityMajor,
+                                         int ComputeCapabilityMinor) const {
+  auto PTXIter =
+      PTXByComputeCapability.find(CUDAPTXInMemorySpec::ComputeCapability{
+          ComputeCapabilityMajor, ComputeCapabilityMinor});
+  if (PTXIter == PTXByComputeCapability.end()) {
+    return nullptr;
+  }
+  return PTXIter->second;
+}
+
+CUDAFatbinInMemorySpec::CUDAFatbinInMemorySpec(llvm::StringRef KernelName,
+                                               const void *Bytes)
+    : KernelLoaderSpec(KernelName), Bytes(Bytes) {}
+
+OpenCLTextInMemorySpec::OpenCLTextInMemorySpec(llvm::StringRef KernelName,
+                                               const char *Text)
+    : KernelLoaderSpec(KernelName), Text(Text) {}
+
+void MultiKernelLoaderSpec::setKernelName(llvm::StringRef KernelName) {
+  if (TheKernelName) {
+    assert(KernelName.equals(*TheKernelName) &&
+           "different kernel names in one MultiKernelLoaderSpec");
+  } else {
+    TheKernelName = llvm::make_unique<std::string>(KernelName);
+  }
+}
+
+MultiKernelLoaderSpec &MultiKernelLoaderSpec::addCUDAPTXInMemory(
+    llvm::StringRef KernelName,
+    llvm::ArrayRef<CUDAPTXInMemorySpec::PTXSpec> SpecList) {
+  assert((TheCUDAPTXInMemorySpec == nullptr) &&
+         "illegal loader spec overwrite");
+  setKernelName(KernelName);
+  TheCUDAPTXInMemorySpec =
+      llvm::make_unique<CUDAPTXInMemorySpec>(KernelName, SpecList);
+  return *this;
+}
+
+MultiKernelLoaderSpec &
+MultiKernelLoaderSpec::addCUDAFatbinInMemory(llvm::StringRef KernelName,
+                                             const void *Bytes) {
+  assert((TheCUDAFatbinInMemorySpec == nullptr) &&
+         "illegal loader spec overwrite");
+  setKernelName(KernelName);
+  TheCUDAFatbinInMemorySpec =
+      llvm::make_unique<CUDAFatbinInMemorySpec>(KernelName, Bytes);
+  return *this;
+}
+
+MultiKernelLoaderSpec &
+MultiKernelLoaderSpec::addOpenCLTextInMemory(llvm::StringRef KernelName,
+                                             const char *OpenCLText) {
+  assert((TheOpenCLTextInMemorySpec == nullptr) &&
+         "illegal loader spec overwrite");
+  setKernelName(KernelName);
+  TheOpenCLTextInMemorySpec =
+      llvm::make_unique<OpenCLTextInMemorySpec>(KernelName, OpenCLText);
+  return *this;
+}
+
+} // namespace streamexecutor
diff --git a/parallel-libs/streamexecutor/lib/unittests/CMakeLists.txt b/parallel-libs/streamexecutor/lib/unittests/CMakeLists.txt
new file mode 100644
index 00000000000..55717aa33c7
--- /dev/null
+++ b/parallel-libs/streamexecutor/lib/unittests/CMakeLists.txt
@@ -0,0 +1,9 @@
+add_executable(
+    kernel_spec_test
+    KernelSpecTest.cpp)
+target_link_libraries(
+    kernel_spec_test
+    streamexecutor
+    ${GTEST_BOTH_LIBRARIES}
+    ${CMAKE_THREAD_LIBS_INIT})
+add_test(KernelSpecTest kernel_spec_test)
diff --git a/parallel-libs/streamexecutor/lib/unittests/KernelSpecTest.cpp b/parallel-libs/streamexecutor/lib/unittests/KernelSpecTest.cpp
new file mode 100644
index 00000000000..fc9eb549968
--- /dev/null
+++ b/parallel-libs/streamexecutor/lib/unittests/KernelSpecTest.cpp
@@ -0,0 +1,132 @@
+//===-- KernelSpecTest.cpp - Tests for KernelSpec -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the unit tests for the code in KernelSpec.
+///
+//===----------------------------------------------------------------------===//
+
+#include "streamexecutor/KernelSpec.h"
+
+#include "gtest/gtest.h"
+
+namespace {
+
+namespace se = ::streamexecutor;
+
+TEST(CUDAPTXInMemorySpec, NoCode) {
+  se::CUDAPTXInMemorySpec Spec("KernelName", {});
+  EXPECT_EQ("KernelName", Spec.getKernelName());
+  EXPECT_EQ(nullptr, Spec.getCode(1, 0));
+}
+
+TEST(CUDAPTXInMemorySpec, SingleComputeCapability) {
+  const char *PTXCodeString = "Dummy PTX code";
+  se::CUDAPTXInMemorySpec Spec("KernelName", {{{1, 0}, PTXCodeString}});
+  EXPECT_EQ("KernelName", Spec.getKernelName());
+  EXPECT_EQ(PTXCodeString, Spec.getCode(1, 0));
+  EXPECT_EQ(nullptr, Spec.getCode(2, 0));
+}
+
+TEST(CUDAPTXInMemorySpec, TwoComputeCapabilities) {
+  const char *PTXCodeString10 = "Dummy PTX code 10";
+  const char *PTXCodeString30 = "Dummy PTX code 30";
+  se::CUDAPTXInMemorySpec Spec(
+      "KernelName", {{{1, 0}, PTXCodeString10}, {{3, 0}, PTXCodeString30}});
+  EXPECT_EQ("KernelName", Spec.getKernelName());
+  EXPECT_EQ(PTXCodeString10, Spec.getCode(1, 0));
+  EXPECT_EQ(PTXCodeString30, Spec.getCode(3, 0));
+  EXPECT_EQ(nullptr, Spec.getCode(2, 0));
+}
+
+TEST(CUDAFatbinInMemorySpec, BasicUsage) {
+  const char *FatbinBytes = "Dummy fatbin bytes";
+  se::CUDAFatbinInMemorySpec Spec("KernelName", FatbinBytes);
+  EXPECT_EQ("KernelName", Spec.getKernelName());
+  EXPECT_EQ(FatbinBytes, Spec.getBytes());
+}
+
+TEST(OpenCLTextInMemorySpec, BasicUsage) {
+  const char *OpenCLText = "Dummy OpenCL text";
+  se::OpenCLTextInMemorySpec Spec("KernelName", OpenCLText);
+  EXPECT_EQ("KernelName", Spec.getKernelName());
+  EXPECT_EQ(OpenCLText, Spec.getText());
+}
+
+TEST(MultiKernelLoaderSpec, NoCode) {
+  se::MultiKernelLoaderSpec MultiSpec;
+  EXPECT_FALSE(MultiSpec.hasCUDAPTXInMemory());
+  EXPECT_FALSE(MultiSpec.hasCUDAFatbinInMemory());
+  EXPECT_FALSE(MultiSpec.hasOpenCLTextInMemory());
+
+  EXPECT_DEBUG_DEATH(MultiSpec.getCUDAPTXInMemory(),
+                     "getting spec that is not present");
+  EXPECT_DEBUG_DEATH(MultiSpec.getCUDAFatbinInMemory(),
+                     "getting spec that is not present");
+  EXPECT_DEBUG_DEATH(MultiSpec.getOpenCLTextInMemory(),
+                     "getting spec that is not present");
+}
+
+TEST(MultiKernelLoaderSpec, Registration) {
+  se::MultiKernelLoaderSpec MultiSpec;
+  const char *KernelName = "KernelName";
+  const char *PTXCodeString = "Dummy PTX code";
+  const char *FatbinBytes = "Dummy fatbin bytes";
+  const char *OpenCLText = "Dummy OpenCL text";
+
+  MultiSpec.addCUDAPTXInMemory(KernelName, {{{1, 0}, PTXCodeString}})
+      .addCUDAFatbinInMemory(KernelName, FatbinBytes)
+      .addOpenCLTextInMemory(KernelName, OpenCLText);
+
+  EXPECT_TRUE(MultiSpec.hasCUDAPTXInMemory());
+  EXPECT_TRUE(MultiSpec.hasCUDAFatbinInMemory());
+  EXPECT_TRUE(MultiSpec.hasOpenCLTextInMemory());
+
+  EXPECT_EQ(KernelName, MultiSpec.getCUDAPTXInMemory().getKernelName());
+  EXPECT_EQ(PTXCodeString, MultiSpec.getCUDAPTXInMemory().getCode(1, 0));
+  EXPECT_EQ(nullptr, MultiSpec.getCUDAPTXInMemory().getCode(2, 0));
+
+  EXPECT_EQ(KernelName, MultiSpec.getCUDAFatbinInMemory().getKernelName());
+  EXPECT_EQ(FatbinBytes, MultiSpec.getCUDAFatbinInMemory().getBytes());
+
+  EXPECT_EQ(KernelName, MultiSpec.getOpenCLTextInMemory().getKernelName());
+  EXPECT_EQ(OpenCLText, MultiSpec.getOpenCLTextInMemory().getText());
+}
+
+TEST(MultiKernelLoaderSpec, RegisterTwice) {
+  se::MultiKernelLoaderSpec MultiSpec;
+  const char *KernelName = "KernelName";
+  const char *FatbinBytes = "Dummy fatbin bytes";
+
+  MultiSpec.addCUDAFatbinInMemory(KernelName, FatbinBytes);
+
+  EXPECT_DEBUG_DEATH(MultiSpec.addCUDAFatbinInMemory(KernelName, FatbinBytes),
+                     "illegal loader spec overwrite");
+}
+
+TEST(MultiKernelLoaderSpec, ConflictingKernelNames) {
+  se::MultiKernelLoaderSpec MultiSpec;
+  const char *KernelNameA = "KernelName";
+  std::string KernelNameB = KernelNameA;
+  const char *PTXCodeString = "Dummy PTX code";
+  const char *FatbinBytes = "Dummy fatbin bytes";
+
+  // Check that names don't conflict if they are equivalent strings in different
+  // locations.
+  MultiSpec.addCUDAPTXInMemory(KernelNameA, {{{1, 0}, PTXCodeString}})
+      .addCUDAFatbinInMemory(KernelNameB, FatbinBytes);
+
+  const char *OtherKernelName = "OtherKernelName";
+  const char *OpenCLText = "Dummy OpenCL text";
+  EXPECT_DEBUG_DEATH(
+      MultiSpec.addOpenCLTextInMemory(OtherKernelName, OpenCLText),
+      "different kernel names in one MultiKernelLoaderSpec");
+}
+
+} // namespace