Reactor: Implement debug info generation

CMakeLists.txt

@@ -81,6 +81,7 @@ option (TSAN "Build with thread sanitizer" 0)
 option (UBSAN "Build with undefined behavior sanitizer" 0)
 option (WARNINGS_AS_ERRORS "Treat all warnings as errors" 1)
 option (DCHECK_ALWAYS_ON "Check validation macros even in release builds" 0)
+option (REACTOR_EMIT_DEBUG_INFO "Emit debug info for JIT functions" 0)
 
 if(ARCH STREQUAL "arm")
     set(DEFAULT_REACTOR_BACKEND "Subzero")
@@ -205,6 +206,9 @@ else()
     set(LLVM_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/llvm-7.0/llvm)
     set(LLVM_CONFIG_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/llvm-7.0/configs)
 endif()
+set(LIBBACKTRACE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/libbacktrace/src)
+set(LIBBACKTRACE_CONFIG_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/libbacktrace/config)
+set(LIBBACKTRACE_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/libbacktrace/src)
 set(SUBZERO_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/subzero)
 set(SUBZERO_LLVM_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/llvm-subzero)
 set(TESTS_DIR ${CMAKE_CURRENT_SOURCE_DIR}/tests)
@@ -293,6 +297,10 @@ else()
         set_cpp_flag("-DDCHECK_ALWAYS_ON")
     endif()
 
+    if(REACTOR_EMIT_DEBUG_INFO)
+        set_cpp_flag("-DENABLE_RR_DEBUG_INFO")
+    endif()
+
     # Disable pedanitc warnings
     if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
         set_cpp_flag("-Wno-ignored-attributes")  # ignoring attributes on template argument 'X'
@@ -1762,18 +1770,28 @@ elseif(ARCH STREQUAL "arm")
         ${LLVM_DIR}/lib/Target/ARM/ARMLegalizerInfo.cpp
         ${LLVM_DIR}/lib/Target/ARM/ARMOptimizeBarriersPass.cpp
     )
- endif()
+endif()
+
+if(REACTOR_EMIT_DEBUG_INFO)
+    list(APPEND LLVM_LIST
+        ${LLVM_DIR}/lib/Demangle/ItaniumDemangle.cpp
+    )
+endif(REACTOR_EMIT_DEBUG_INFO)
 
 set(LLVM_INCLUDE_DIR "")
 
 if(WIN32)
     list(APPEND LLVM_INCLUDE_DIR ${LLVM_CONFIG_DIR}/windows/include)
+    list(APPEND LIBBACKTRACE_INCLUDE_DIR ${LIBBACKTRACE_CONFIG_DIR}/windows/include)
 elseif(LINUX)
     list(APPEND LLVM_INCLUDE_DIR ${LLVM_CONFIG_DIR}/linux/include)
+    list(APPEND LIBBACKTRACE_INCLUDE_DIR ${LIBBACKTRACE_CONFIG_DIR}/linux/include)
 elseif(APPLE)
     list(APPEND LLVM_INCLUDE_DIR ${LLVM_CONFIG_DIR}/darwin/include)
+    list(APPEND LIBBACKTRACE_INCLUDE_DIR ${LIBBACKTRACE_CONFIG_DIR}/darwin/include)
 elseif(ANDROID)
     list(APPEND LLVM_INCLUDE_DIR ${LLVM_CONFIG_DIR}/android/include)
+    list(APPEND LIBBACKTRACE_INCLUDE_DIR ${LIBBACKTRACE_CONFIG_DIR}/android/include)
 endif()
 
 list(APPEND LLVM_INCLUDE_DIR
@@ -1962,6 +1980,7 @@ set(COMMON_INCLUDE_DIR
     ${SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/include
     ${LLVM_INCLUDE_DIR}
+    ${LIBBACKTRACE_INCLUDE_DIR}
 )
 set(OPENGL_INCLUDE_DIR
     ${OPENGL_DIR}
@@ -2002,9 +2021,41 @@ list(REMOVE_ITEM SWIFTSHADER_LIST
     ${SOURCE_DIR}/Common/GrallocAndroid.hpp
 )
 
+if(REACTOR_EMIT_DEBUG_INFO)
+    set(LIBBACKTRACE_LIST
+        ${LIBBACKTRACE_DIR}/atomic.c
+        ${LIBBACKTRACE_DIR}/backtrace.c
+        ${LIBBACKTRACE_DIR}/backtrace.h
+        ${LIBBACKTRACE_DIR}/dwarf.c
+        ${LIBBACKTRACE_DIR}/fileline.c
+        ${LIBBACKTRACE_DIR}/filenames.h
+        ${LIBBACKTRACE_DIR}/internal.h
+        ${LIBBACKTRACE_DIR}/mmap.c
+        ${LIBBACKTRACE_DIR}/mmapio.c
+        ${LIBBACKTRACE_DIR}/posix.c
+        ${LIBBACKTRACE_DIR}/print.c
+        ${LIBBACKTRACE_DIR}/simple.c
+        ${LIBBACKTRACE_DIR}/sort.c
+        ${LIBBACKTRACE_DIR}/state.c
+        ${LIBBACKTRACE_INCLUDE_DIR}/backtrace-supported.h
+        ${LIBBACKTRACE_INCLUDE_DIR}/config.h
+    )
+
+    if(WIN32)
+        list(APPEND LIBBACKTRACE_LIST ${LIBBACKTRACE_DIR}/pecoff.c)
+    elseif(LINUX)
+        list(APPEND LIBBACKTRACE_LIST ${LIBBACKTRACE_DIR}/elf.c)
+    elseif(APPLE)
+        message(FATAL_ERROR "libbacktrace does not support mach-o yet")
+    endif()
+endif(REACTOR_EMIT_DEBUG_INFO)
+
 set(REACTOR_LLVM_LIST
     ${SOURCE_DIR}/Reactor/Reactor.cpp
     ${SOURCE_DIR}/Reactor/LLVMReactor.cpp
+    ${SOURCE_DIR}/Reactor/LLVMReactor.hpp
+    ${SOURCE_DIR}/Reactor/LLVMReactorDebugInfo.cpp
+    ${SOURCE_DIR}/Reactor/LLVMReactorDebugInfo.hpp
     ${SOURCE_DIR}/Reactor/Nucleus.hpp
     ${SOURCE_DIR}/Reactor/Routine.cpp
     ${SOURCE_DIR}/Reactor/Routine.hpp
@@ -2202,6 +2253,17 @@ set_target_properties(ReactorLLVM PROPERTIES
 )
 target_link_libraries(ReactorLLVM llvm ${OS_LIBS})
 
+if(REACTOR_EMIT_DEBUG_INFO)
+    add_library(Libbacktrace STATIC ${LIBBACKTRACE_LIST})
+    set_target_properties(Libbacktrace PROPERTIES
+        INCLUDE_DIRECTORIES "${LIBBACKTRACE_INCLUDE_DIR}"
+        POSITION_INDEPENDENT_CODE 1
+        FOLDER "Core"
+    )
+    target_link_libraries(Libbacktrace ${OS_LIBS})
+    target_link_libraries(ReactorLLVM Libbacktrace)
+endif(REACTOR_EMIT_DEBUG_INFO)
+
 if(${REACTOR_BACKEND} STREQUAL "LLVM")
     set(Reactor ReactorLLVM)
 elseif(${REACTOR_BACKEND} STREQUAL "Subzero")

build/Visual Studio 15 2017 Win64/ReactorLLVM.vcxproj

@@ -122,7 +122,10 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClCompile Include="$(SolutionDir)src\Reactor\Reactor.cpp" />
-    <ClCompile Include="$(SolutionDir)src\Reactor\LLVMReactor.cpp" />
+    <ClCompile Include="$(SolutionDir)src\Reactor\LLVMReactor.cpp"  />
+    <ClInclude Include="$(SolutionDir)src\Reactor\LLVMReactor.hpp" />
+    <ClCompile Include="$(SolutionDir)src\Reactor\LLVMReactorDebugInfo.cpp"  />
+    <ClInclude Include="$(SolutionDir)src\Reactor\LLVMReactorDebugInfo.hpp" />
     <ClInclude Include="$(SolutionDir)src\Reactor\Nucleus.hpp" />
     <ClCompile Include="$(SolutionDir)src\Reactor\Routine.cpp" />
     <ClInclude Include="$(SolutionDir)src\Reactor\Routine.hpp" />

build/Visual Studio 15 2017 Win64/ReactorLLVM.vcxproj.filters

@@ -7,6 +7,9 @@
     <ClCompile Include="$(SolutionDir)src\Reactor\LLVMReactor.cpp">
       <Filter>src\Reactor</Filter>
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)src\Reactor\LLVMReactorDebugInfo.cpp">
+      <Filter>src\Reactor</Filter>
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)src\Reactor\Routine.cpp">
       <Filter>src\Reactor</Filter>
     </ClCompile>
@@ -33,6 +36,12 @@
     <ClInclude Include="$(SolutionDir)src\Reactor\Routine.hpp">
       <Filter>src\Reactor</Filter>
     </ClInclude>
+    <ClInclude Include="$(SolutionDir)src\Reactor\LLVMReactor.hpp">
+      <Filter>src\Reactor</Filter>
+    </ClInclude>
+    <ClInclude Include="$(SolutionDir)src\Reactor\LLVMReactorDebugInfo.hpp">
+      <Filter>src\Reactor</Filter>
+    </ClInclude>
     <ClInclude Include="$(SolutionDir)src\Reactor\LLVMRoutine.hpp">
       <Filter>src\Reactor</Filter>
     </ClInclude>

docs/ReactorDebugInfo.md

+# Reactor Debug Info Generation
+
+## Introduction
+
+Reactor produces Just In Time compiled dynamic executable code and can be used to JIT high performance functions specialized for runtime
+configurations, or to even build a compiler.
+
+In order to debug executable code at a higher level than disassembly, source code files are required.
+
+Reactor has two potential sources of source code:
+
+1. The C++ source code of the program that calls into Reactor.
+2. External source files read by the program and passed to Reactor.
+
+While case (2) is preferable for implementing a compiler, this is currently not
+implemented.
+
+Reactor implements case (1) and this can be used by GDB to single line step and
+inspect variables.
+
+## Supported Platforms
+
+Currently:
+
+* Debug info generation is only supported on Linux with the LLVM 7
+backend.
+* GDB is the only supported debugger.
+* The program must be compiled with debug info iteself.
+
+## Enabling
+
+Debug generation is enabled with `REACTOR_EMIT_DEBUG_INFO` CMake flag (defaults
+to disabled).
+
+## Implementation details
+
+### Source Location
+
+All Reactor functions begin with a call to `RR_DEBUG_INFO_UPDATE_LOC()`, which calls into `rr::DebugInfo::EmitLocation()`.
+
+`rr::DebugInfo::EmitLocation()` calls `rr::DebugInfo::getCallerBacktrace()`,
+which in turn uses [`libbacktrace`](https://github.com/ianlancetaylor/libbacktrace)
+to unwind the stack and find the file, function and line of the caller.
+
+This information is passed to `llvm::IRBuilder<>::SetCurrentDebugLocation`
+to emit source line information for the next LLVM instructions to be built.
+
+### Variables
+
+There are 3 aspects to generating variable debug information:
+
+#### 1. Variable names
+
+Constructing a Reactor `LValue`:
+
+```C++
+rr::Int a = 1;
+```
+
+Will emit an LLVM `alloca` instruction to allocate the storage of the variable,
+and emit another to initialize it to the constant `1`. While fluent, none of the
+Reactor calls see the name of the C++ local variable "`a`", and the LLVM `alloca`
+value gets a meaningless numerical value.
+
+There are two potential ways that Reactor can obtain the variable name:
+
+1. Use the running executable's own debug information to examine the local
+   declaration and extract the local variable's name.
+2. Use the backtrace information to parse the name from the source file.
+
+While (1) is arguably a cleaner and more robust solution, (2) is
+easier to implement and can work for the majority of use cases.
+
+(2) is the current solution implemented.
+
+`rr::DebugInfo::getOrParseFileTokens()` scans a source file line by line, and
+uses a regular expression to look for patterns of `<type> <name>`. Matching is not
+precise, but is adequate to find locals constructed with and without assignment.
+
+#### 2. Variable binding
+
+Given that we can find a variable name for a given source line, we need a way of
+binding the LLVM values to the name.
+
+Given our trivial example:
+
+```C++
+rr::Int a = 1
+```
+
+The `rr::Int` constructor calls `RR_DEBUG_INFO_EMIT_VAR()` passing the storage
+value as single argument. `RR_DEBUG_INFO_EMIT_VAR()` performs the backtrace
+to find the source file and line and uses the token information produced by
+`rr::DebugInfo::getOrParseFileTokens()` to identify the variable name.
+
+However, things get a bit more complicated when there are multiple variables
+being constructed on the same line.
+
+Take for example:
+
+```C++
+rr::Int a = rr::Int(1) + rr::Int(2)
+```
+
+Here we have 3 calls to the `rr::Int` constructor, each calling down
+to `RR_DEBUG_INFO_EMIT_VAR()`.
+
+To disambiguate which of these should be bound to the variable name "`a`",
+`rr::DebugInfo::EmitVariable()` buffers the binding into
+`scope.pending` and the last binding for a given line is used by
+`DebugInfo::emitPending()`. For variable construction and assignment, C++
+guarantees that the LHS is the last value to be constructed.
+
+This solution is not perfect.
+
+Multi-line expressions, multiple assignments on a single line, macro obfuscation
+can all break variable bindings - however the majority of typical cases work.
+
+#### 3. Variable scope
+
+`rr::DebugInfo` maintains a stack of `llvm::DIScope`s and `llvm::DILocation`s
+that mirrors the current backtrace for function being called.
+
+A synthetic call stack is produced by chaining `llvm::DILocation`s with
+`InlinedAt`s.
+
+For example, at the declaration of `i`:
+
+```C++
+void B()
+{
+    rr::Int i; // <- here
+}
+
+void A()
+{
+    B();
+}
+
+int main(int argc, const char* argv[])
+{
+    A();
+}
+```
+
+The `DIScope` hierarchy would be:
+
+```C++
+                              DIFile: "foo.cpp"
+rr::DebugInfo::diScope[0].di: ↳ DISubprogram: "main"
+rr::DebugInfo::diScope[1].di: ↳ DISubprogram: "A"
+rr::DebugInfo::diScope[2].di: ↳ DISubprogram: "B"
+```
+
+The `DILocation` hierarchy would be:
+
+```C++
+rr::DebugInfo::diRootLocation:      DILocation(DISubprogram: "ReactorFunction")
+rr::DebugInfo::diScope[0].location: ↳ DILocation(DISubprogram: "main")
+rr::DebugInfo::diScope[1].location:   ↳ DILocation(DISubprogram: "A")
+rr::DebugInfo::diScope[2].location:     ↳ DILocation(DISubprogram: "B")
+```
+
+Where '↳' represents an `InlinedAt`.
+
+
+`rr::DebugInfo::diScope` is updated by `rr::DebugInfo::syncScope()`.
+
+`llvm::DIScope`s typically do not nest - there is usually a separate
+`llvm::DISubprogram` for each function in the callstack. All local variables
+within a function will typically share the same scope, regardless of whether
+they are declared within a sub-block.
+
+Loops and jumps within a function add complexity. Consider:
+
+```C++
+void B()
+{
+    rr::Int i = 0;
+}
+
+void A()
+{
+    for (int i = 0; i < 3; i++)
+    {
+        rr::Int x = 0;
+    }
+    B();
+}
+
+int main(int argc, const char* argv[])
+{
+    A();
+}
+```
+
+In this particular example Reactor will not be aware of the `for` loop, and will
+attempt to create three variables called "`x`" in the same function scope for `A()`.
+Duplicate symbols in the same `llvm::DIScope` result in undefined behavior.
+
+To solve this, `rr::DebugInfo::syncScope()` observes when a function jumps
+backwards, and forks the current `llvm::DILexicalBlock` for the function. This
+results in a number of `llvm::DILexicalBlock` chains, each declaring variables
+that shadow the previous block.
+
+At the declaration of `i`, the `DIScope` hierarchy would be:
+
+```C++
+                              DIFile: "foo.cpp"
+rr::DebugInfo::diScope[0].di: ↳ DISubprogram: "main"
+                              ↳ DISubprogram: "A"
+                              | ↳ DILexicalBlock: "A".1
+rr::DebugInfo::diScope[1].di: |   ↳ DILexicalBlock: "A".2
+rr::DebugInfo::diScope[2].di: ↳ DISubprogram: "B"
+```
+
+The `DILocation` hierarchy would be:
+
+```C++
+rr::DebugInfo::diRootLocation:      DILocation(DISubprogram: "ReactorFunction")
+rr::DebugInfo::diScope[0].location: ↳ DILocation(DISubprogram: "main")
+rr::DebugInfo::diScope[1].location:   ↳ DILocation(DILexicalBlock: "A".2)
+rr::DebugInfo::diScope[2].location:     ↳ DILocation(DISubprogram: "B")
+```
+
+### Debugger integration
+
+Once the debug information has been generated, it needs to be handed to the
+debugger.
+
+Reactor uses [`llvm::JITEventListener::createGDBRegistrationListener()`](http://llvm.org/doxygen/classllvm_1_1JITEventListener.html#a004abbb5a0d48ac376dfbe3e3c97c306)
+to inform GDB of the JIT'd program and its debugging information.
+More information [can be found here](https://llvm.org/docs/DebuggingJITedCode.html).
+
+LLDB should be able to support this same mechanism, but at the time of writing
+this does not appear to work.
+

src/Reactor/LLVMReactor.hpp

+// Copyright 2019 The SwiftShader Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef rr_LLVMReactor_hpp
+#define rr_LLVMReactor_hpp
+
+namespace llvm
+{
+	class Type;
+	class Value;
+}
+
+namespace rr
+{
+	class Type;
+	class Value;
+
+	llvm::Type *T(Type *t);
+
+	inline Type *T(llvm::Type *t)
+	{
+		return reinterpret_cast<Type*>(t);
+	}
+
+	inline llvm::Value *V(Value *t)
+	{
+		return reinterpret_cast<llvm::Value*>(t);
+	}
+
+	inline Value *V(llvm::Value *t)
+	{
+		return reinterpret_cast<Value*>(t);
+	}
+
+	// Emits a no-op instruction that will not be optimized away.
+	// Useful for emitting something that can have a source location without
+	// effect.
+	void Nop();
+}
+
+#endif // rr_LLVMReactor_hpp

src/Reactor/LLVMReactorDebugInfo.hpp

+// Copyright 2019 The SwiftShader Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef rr_LLVMReactorDebugInfo_hpp
+#define rr_LLVMReactorDebugInfo_hpp
+
+#include "Reactor.hpp"
+
+#ifdef ENABLE_RR_DEBUG_INFO
+
+#include <unordered_set>
+#include <unordered_map>
+#include <vector>
+#include <memory>
+
+// Forward declarations
+namespace llvm
+{
+	class BasicBlock;
+	class ConstantFolder;
+	class DIBuilder;
+	class DICompileUnit;
+	class DIFile;
+	class DILocation;
+	class DIScope;
+	class DISubprogram;
+	class DIType;
+	class Function;
+	class Instruction;
+	class IRBuilderDefaultInserter;
+	class JITEventListener;
+	class LLVMContext;
+	class LoadedObjectInfo;
+	class Module;
+	class Type;
+	class Value;
+
+	namespace object
+	{
+		class ObjectFile;
+	}
+
+	template <typename T, typename Inserter> class IRBuilder;
+} // namespace llvm
+
+namespace rr
+{
+	class Type;
+	class Value;
+
+	// DebugInfo generates LLVM DebugInfo IR from the C++ source that calls
+	// into Reactor functions. See docs/ReactorDebugInfo.mk for more information.
+	class DebugInfo
+	{
+	public:
+		using IRBuilder = llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>;
+
+		DebugInfo(IRBuilder *builder,
+				llvm::LLVMContext *context,
+				llvm::Module *module,
+				llvm::Function *function);
+
+		// Finalize debug info generation. Must be called before the LLVM module
+		// is built.
+		void Finalize();
+
+		// Updates the current source location.
+		void EmitLocation();
+
+		// Binds the value to its symbol in the source file.
+		// See docs/ReactorDebugInfo.mk for more information.
+		void EmitVariable(Value *value);
+
+		// Forcefully flush the binding of the last variable name.
+		// Used for binding the initializer of `For` loops.
+		void Flush();
+
+		// NotifyObjectEmitted informs any attached debuggers of the JIT'd
+		// object.
+		void NotifyObjectEmitted(const llvm::object::ObjectFile &Obj, const llvm::LoadedObjectInfo &L);
+
+		// NotifyFreeingObject informs any attached debuggers that the JIT'd
+		// object is now invalid.
+		void NotifyFreeingObject(const llvm::object::ObjectFile &Obj);
+
+	private:
+		struct Token
+		{
+			enum Kind
+			{
+				Identifier,
+				Return
+			};
+			Kind kind;
+			std::string identifier;
+		};
+
+		using LineTokens = std::unordered_map<unsigned int, Token>;
+
+		struct FunctionLocation
+		{
+			std::string name;
+			std::string file;
+
+			bool operator == (const FunctionLocation &rhs) const { return name == rhs.name && file == rhs.file; }
+			bool operator != (const FunctionLocation &rhs) const { return !(*this == rhs); }
+
+			struct Hash
+			{
+				std::size_t operator()(const FunctionLocation &l) const noexcept
+				{
+					return std::hash<std::string>()(l.file) * 31 +
+							std::hash<std::string>()(l.name);
+				}
+			};
+		};
+
+		struct Location
+		{
+			FunctionLocation function;
+			unsigned int line = 0;
+
+			bool operator == (const Location &rhs) const { return function == rhs.function && line == rhs.line; }
+			bool operator != (const Location &rhs) const { return !(*this == rhs); }
+
+			struct Hash
+			{
+				std::size_t operator()(const Location &l) const noexcept
+				{
+					return FunctionLocation::Hash()(l.function) * 31 +
+							std::hash<unsigned int>()(l.line);
+				}
+			};
+		};
+
+		using Backtrace = std::vector<Location>;
+
+		struct Pending
+		{
+			std::string name;
+			Location location;
+			llvm::DILocation *diLocation = nullptr;
+			llvm::Value *value = nullptr;
+			llvm::Instruction *insertAfter = nullptr;
+			llvm::BasicBlock *block = nullptr;
+			llvm::DIScope *scope = nullptr;
+			bool addNopOnNextLine = false;
+		};
+
+		struct Scope
+		{
+			Location location;
+			llvm::DIScope *di;
+			std::unordered_set<std::string> symbols;
+			Pending pending;
+		};
+
+		void registerBasicTypes();
+
+		void emitPending(Scope &scope, IRBuilder *builder, llvm::DIBuilder *diBuilder);
+
+		// Returns the source location of the non-Reactor calling function.
+		Location getCallerLocation() const;
+
+		// Returns the backtrace for the callstack, starting at the first
+		// non-Reactor file. If limit is non-zero, then a maximum of limit
+		// frames will be returned.
+		Backtrace getCallerBacktrace(size_t limit = 0) const;
+
+		llvm::DILocation* getLocation(const Backtrace &backtrace, size_t i);
+
+		llvm::DIType *getOrCreateType(llvm::Type* type);
+		llvm::DIFile *getOrCreateFile(const char* path);
+		LineTokens const *getOrParseFileTokens(const char* path);
+
+		// Synchronizes diScope with the current backtrace.
+		void syncScope(Backtrace const& backtrace);
+
+		IRBuilder *builder;
+		llvm::LLVMContext *context;
+		llvm::Module *module;
+		llvm::Function *function;
+
+		llvm::DIBuilder *diBuilder;
+		llvm::DICompileUnit *diCU;
+		llvm::DISubprogram *diSubprogram;
+		llvm::DILocation *diRootLocation;
+		std::vector<Scope> diScope;
+		std::unordered_map<std::string, llvm::DIFile*> diFiles;
+		std::unordered_map<llvm::Type*, llvm::DIType*> diTypes;
+		std::unordered_map<std::string, std::unique_ptr<LineTokens>> fileTokens;
+		llvm::JITEventListener *jitEventListener;
+		std::vector<void const*> pushed;
+	};
+
+} // namespace rr
+
+#endif // ENABLE_RR_DEBUG_INFO
+
+#endif // rr_LLVMReactorDebugInfo_hpp

src/Reactor/Reactor.vcxproj

@@ -289,6 +289,7 @@
     <ClCompile Include="LLVMRoutine.cpp" />
     <ClCompile Include="LLVMRoutineManager.cpp" />
     <ClCompile Include="LLVMReactor.cpp" />
+    <ClCompile Include="LLVMReactorDebugInfo.cpp" />
     <ClCompile Include="ExecutableMemory.cpp" />
     <ClCompile Include="Reactor.cpp" />
     <ClCompile Include="Routine.cpp" />
@@ -297,6 +298,8 @@
   <ItemGroup>
     <ClInclude Include="CPUID.hpp" />
     <ClInclude Include="Debug.hpp" />
+    <ClInclude Include="LLVMReactor.hpp" />
+    <ClInclude Include="LLVMReactorDebugInfo.hpp" />
     <ClInclude Include="LLVMRoutine.hpp" />
     <ClInclude Include="LLVMRoutineManager.hpp" />
     <ClInclude Include="ExecutableMemory.hpp" />

src/Reactor/Reactor.vcxproj.filters

@@ -27,6 +27,9 @@
     <ClCompile Include="LLVMReactor.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="LLVMReactorDebugInfo.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
     <ClCompile Include="CPUID.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
@@ -56,6 +59,12 @@
     <ClInclude Include="Routine.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="LLVMReactor.hpp">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="LLVMReactorDebugInfo.hpp">
+      <Filter>Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="LLVMRoutineManager.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>

src/Reactor/SubzeroReactor.cpp

@@ -3425,4 +3425,8 @@ namespace rr
 	RValue<Float4> Log2(RValue<Float4> x) { UNIMPLEMENTED("Subzero Log2()"); return Float4(0); }
 	RValue<UInt4> Ctlz(RValue<UInt4> x, bool isZeroUndef) { UNIMPLEMENTED("Subzero Ctlz()"); return UInt4(0); }
 	RValue<UInt4> Cttz(RValue<UInt4> x, bool isZeroUndef) { UNIMPLEMENTED("Subzero Cttz()"); return UInt4(0); }
+
+	void EmitDebugLocation() {}
+	void EmitDebugVariable(Value* value) {}
+	void FlushDebug() {}
 }

third_party/libbacktrace/config/darwin/include/backtrace-supported.h

+/* backtrace-supported.h.in -- Whether stack backtrace is supported.
+   Copyright (C) 2012-2016 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor, Google.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    (1) Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    (2) Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+
+    (3) The name of the author may not be used to
+    endorse or promote products derived from this software without
+    specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.  */
+
+/* The file backtrace-supported.h.in is used by configure to generate
+   the file backtrace-supported.h.  The file backtrace-supported.h may
+   be #include'd to see whether the backtrace library will be able to
+   get a backtrace and produce symbolic information.  */
+
+
+/* BACKTRACE_SUPPORTED will be #define'd as 1 if the backtrace library
+   should work, 0 if it will not.  Libraries may #include this to make
+   other arrangements.  */
+
+#define BACKTRACE_SUPPORTED 1
+
+/* BACKTRACE_USES_MALLOC will be #define'd as 1 if the backtrace
+   library will call malloc as it works, 0 if it will call mmap
+   instead.  This may be used to determine whether it is safe to call
+   the backtrace functions from a signal handler.  In general this
+   only applies to calls like backtrace and backtrace_pcinfo.  It does
+   not apply to backtrace_simple, which never calls malloc.  It does
+   not apply to backtrace_print, which always calls fprintf and
+   therefore malloc.  */
+
+#define BACKTRACE_USES_MALLOC 0
+
+/* BACKTRACE_SUPPORTS_THREADS will be #define'd as 1 if the backtrace
+   library is configured with threading support, 0 if not.  If this is
+   0, the threaded parameter to backtrace_create_state must be passed
+   as 0.  */
+
+#define BACKTRACE_SUPPORTS_THREADS 1
+
+/* BACKTRACE_SUPPORTS_DATA will be #defined'd as 1 if the backtrace_syminfo
+   will work for variables.  It will always work for functions.  */
+
+#define BACKTRACE_SUPPORTS_DATA 1

third_party/libbacktrace/config/darwin/include/config.h

+/* config.h.  Generated from config.h.in by configure.  */
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* ELF size: 32 or 64 */
+#define BACKTRACE_ELF_SIZE 64
+
+/* XCOFF size: 32 or 64 */
+#define BACKTRACE_XCOFF_SIZE unused
+
+/* Define to 1 if you have the __atomic functions */
+#define HAVE_ATOMIC_FUNCTIONS 1
+
+/* Define to 1 if you have the `clock_gettime' function. */
+#define HAVE_CLOCK_GETTIME 1
+
+/* Define to 1 if you have the declaration of `strnlen', and to 0 if you
+   don't. */
+#define HAVE_DECL_STRNLEN 1
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#define HAVE_DLFCN_H 1
+
+/* Define if dl_iterate_phdr is available. */
+/* #undef HAVE_DL_ITERATE_PHDR */
+
+/* Define to 1 if you have the fcntl function */
+#define HAVE_FCNTL 1
+
+/* Define if getexecname is available. */
+/* #undef HAVE_GETEXECNAME */
+
+/* Define if _Unwind_GetIPInfo is available. */
+#define HAVE_GETIPINFO 1
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#define HAVE_INTTYPES_H 1
+
+/* Define to 1 if you have the `z' library (-lz). */
+#define HAVE_LIBZ 1
+
+/* Define to 1 if you have the <link.h> header file. */
+/* #undef HAVE_LINK_H */
+
+/* Define if AIX loadquery is available. */
+/* #undef HAVE_LOADQUERY */
+
+/* Define to 1 if you have the `lstat' function. */
+#define HAVE_LSTAT 1
+
+/* Define to 1 if you have the <memory.h> header file. */
+#define HAVE_MEMORY_H 1
+
+/* Define to 1 if you have the `readlink' function. */
+#define HAVE_READLINK 1
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#define HAVE_STDINT_H 1
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#define HAVE_STDLIB_H 1
+
+/* Define to 1 if you have the <strings.h> header file. */
+#define HAVE_STRINGS_H 1
+
+/* Define to 1 if you have the <string.h> header file. */
+#define HAVE_STRING_H 1
+
+/* Define to 1 if you have the __sync functions */
+#define HAVE_SYNC_FUNCTIONS 1
+
+/* Define to 1 if you have the <sys/ldr.h> header file. */
+/* #undef HAVE_SYS_LDR_H */
+
+/* Define to 1 if you have the <sys/mman.h> header file. */
+#define HAVE_SYS_MMAN_H 1
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#define HAVE_SYS_STAT_H 1
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#define HAVE_SYS_TYPES_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#define HAVE_UNISTD_H 1
+
+/* Define if -lz is available. */
+#define HAVE_ZLIB 1
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+#define LT_OBJDIR ".libs/"
+
+/* Define to the address where bug reports for this package should be sent. */
+#define PACKAGE_BUGREPORT ""
+
+/* Define to the full name of this package. */
+#define PACKAGE_NAME "package-unused"
+
+/* Define to the full name and version of this package. */
+#define PACKAGE_STRING "package-unused version-unused"
+
+/* Define to the one symbol short name of this package. */
+#define PACKAGE_TARNAME "libbacktrace"
+
+/* Define to the home page for this package. */
+#define PACKAGE_URL ""
+
+/* Define to the version of this package. */
+#define PACKAGE_VERSION "version-unused"
+
+/* Define to 1 if you have the ANSI C header files. */
+#define STDC_HEADERS 1
+
+/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# define _ALL_SOURCE 1
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE 1
+#endif
+/* Enable threading extensions on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# define _POSIX_PTHREAD_SEMANTICS 1
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# define _TANDEM_SOURCE 1
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# define __EXTENSIONS__ 1
+#endif
+
+
+/* Number of bits in a file offset, on hosts where this is settable. */
+/* #undef _FILE_OFFSET_BITS */
+
+/* Define for large files, on AIX-style hosts. */
+/* #undef _LARGE_FILES */
+
+/* Define to 1 if on MINIX. */
+/* #undef _MINIX */
+
+/* Define to 2 if the system does not provide POSIX.1 features except with
+   this defined. */
+/* #undef _POSIX_1_SOURCE */
+
+/* Define to 1 if you need to in order for `stat' and other things to work. */
+/* #undef _POSIX_SOURCE */

third_party/libbacktrace/config/linux/include/backtrace-supported.h

+/* backtrace-supported.h.in -- Whether stack backtrace is supported.
+   Copyright (C) 2012-2016 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor, Google.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    (1) Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    (2) Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+
+    (3) The name of the author may not be used to
+    endorse or promote products derived from this software without
+    specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.  */
+
+/* The file backtrace-supported.h.in is used by configure to generate
+   the file backtrace-supported.h.  The file backtrace-supported.h may
+   be #include'd to see whether the backtrace library will be able to
+   get a backtrace and produce symbolic information.  */
+
+
+/* BACKTRACE_SUPPORTED will be #define'd as 1 if the backtrace library
+   should work, 0 if it will not.  Libraries may #include this to make
+   other arrangements.  */
+
+#define BACKTRACE_SUPPORTED 1
+
+/* BACKTRACE_USES_MALLOC will be #define'd as 1 if the backtrace
+   library will call malloc as it works, 0 if it will call mmap
+   instead.  This may be used to determine whether it is safe to call
+   the backtrace functions from a signal handler.  In general this
+   only applies to calls like backtrace and backtrace_pcinfo.  It does
+   not apply to backtrace_simple, which never calls malloc.  It does
+   not apply to backtrace_print, which always calls fprintf and
+   therefore malloc.  */
+
+#define BACKTRACE_USES_MALLOC 0
+
+/* BACKTRACE_SUPPORTS_THREADS will be #define'd as 1 if the backtrace
+   library is configured with threading support, 0 if not.  If this is
+   0, the threaded parameter to backtrace_create_state must be passed
+   as 0.  */
+
+#define BACKTRACE_SUPPORTS_THREADS 1
+
+/* BACKTRACE_SUPPORTS_DATA will be #defined'd as 1 if the backtrace_syminfo
+   will work for variables.  It will always work for functions.  */
+
+#define BACKTRACE_SUPPORTS_DATA 1

third_party/libbacktrace/config/linux/include/config.h

+/* config.h.  Generated from config.h.in by configure.  */
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* ELF size: 32 or 64 */
+#define BACKTRACE_ELF_SIZE 64
+
+/* XCOFF size: 32 or 64 */
+#define BACKTRACE_XCOFF_SIZE unused
+
+/* Define to 1 if you have the __atomic functions */
+#define HAVE_ATOMIC_FUNCTIONS 1
+
+/* Define to 1 if you have the `clock_gettime' function. */
+#define HAVE_CLOCK_GETTIME 1
+
+/* Define to 1 if you have the declaration of `strnlen', and to 0 if you
+   don't. */
+#define HAVE_DECL_STRNLEN 1
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#define HAVE_DLFCN_H 1
+
+/* Define if dl_iterate_phdr is available. */
+#define HAVE_DL_ITERATE_PHDR 1
+
+/* Define to 1 if you have the fcntl function */
+#define HAVE_FCNTL 1
+
+/* Define if getexecname is available. */
+/* #undef HAVE_GETEXECNAME */
+
+/* Define if _Unwind_GetIPInfo is available. */
+#define HAVE_GETIPINFO 1
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#define HAVE_INTTYPES_H 1
+
+/* Define to 1 if you have the `z' library (-lz). */
+#define HAVE_LIBZ 1
+
+/* Define to 1 if you have the <link.h> header file. */
+#define HAVE_LINK_H 1
+
+/* Define if AIX loadquery is available. */
+/* #undef HAVE_LOADQUERY */
+
+/* Define to 1 if you have the `lstat' function. */
+#define HAVE_LSTAT 1
+
+/* Define to 1 if you have the <memory.h> header file. */
+#define HAVE_MEMORY_H 1
+
+/* Define to 1 if you have the `readlink' function. */
+#define HAVE_READLINK 1
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#define HAVE_STDINT_H 1
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#define HAVE_STDLIB_H 1
+
+/* Define to 1 if you have the <strings.h> header file. */
+#define HAVE_STRINGS_H 1
+
+/* Define to 1 if you have the <string.h> header file. */
+#define HAVE_STRING_H 1
+
+/* Define to 1 if you have the __sync functions */
+#define HAVE_SYNC_FUNCTIONS 1
+
+/* Define to 1 if you have the <sys/ldr.h> header file. */
+/* #undef HAVE_SYS_LDR_H */
+
+/* Define to 1 if you have the <sys/mman.h> header file. */
+#define HAVE_SYS_MMAN_H 1
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#define HAVE_SYS_STAT_H 1
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#define HAVE_SYS_TYPES_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#define HAVE_UNISTD_H 1
+
+/* Define if -lz is available. */
+#define HAVE_ZLIB 1
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+#define LT_OBJDIR ".libs/"
+
+/* Define to the address where bug reports for this package should be sent. */
+#define PACKAGE_BUGREPORT ""
+
+/* Define to the full name of this package. */
+#define PACKAGE_NAME "package-unused"
+
+/* Define to the full name and version of this package. */
+#define PACKAGE_STRING "package-unused version-unused"
+
+/* Define to the one symbol short name of this package. */
+#define PACKAGE_TARNAME "libbacktrace"
+
+/* Define to the home page for this package. */
+#define PACKAGE_URL ""
+
+/* Define to the version of this package. */
+#define PACKAGE_VERSION "version-unused"
+
+/* Define to 1 if you have the ANSI C header files. */
+#define STDC_HEADERS 1
+
+/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# define _ALL_SOURCE 1
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE 1
+#endif
+/* Enable threading extensions on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# define _POSIX_PTHREAD_SEMANTICS 1
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# define _TANDEM_SOURCE 1
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# define __EXTENSIONS__ 1
+#endif
+
+
+/* Number of bits in a file offset, on hosts where this is settable. */
+/* #undef _FILE_OFFSET_BITS */
+
+/* Define for large files, on AIX-style hosts. */
+/* #undef _LARGE_FILES */
+
+/* Define to 1 if on MINIX. */
+/* #undef _MINIX */
+
+/* Define to 2 if the system does not provide POSIX.1 features except with
+   this defined. */
+/* #undef _POSIX_1_SOURCE */
+
+/* Define to 1 if you need to in order for `stat' and other things to work. */
+/* #undef _POSIX_SOURCE */