Added a setting that enables saving all .o files from a given JIT expression.

This allows debugging of the JIT and other analyses of the internals of the
expression parser.  I've also added a testcase that verifies that the setting
works correctly when off and on.

llvm-svn: 282434

lldb/include/lldb/Expression/IRExecutionUnit.h

@@ -33,6 +33,7 @@ namespace llvm {
 
 class Module;
 class ExecutionEngine;
+class ObjectCache;
 
 } // namespace llvm
 
@@ -398,6 +399,7 @@ private:
 
   std::unique_ptr<llvm::LLVMContext> m_context_ap;
   std::unique_ptr<llvm::ExecutionEngine> m_execution_engine_ap;
+  std::unique_ptr<llvm::ObjectCache> m_object_cache_ap;
   std::unique_ptr<llvm::Module>
       m_module_ap;        ///< Holder for the module until it's been handed off
   llvm::Module *m_module; ///< Owned by the execution engine

lldb/include/lldb/Target/Target.h

@@ -128,6 +128,8 @@ public:
 
   bool GetEnableNotifyAboutFixIts() const;
 
+  bool GetEnableSaveObjects() const;
+
   bool GetEnableSyntheticValue() const;
 
   uint32_t GetMaximumNumberOfChildrenToDisplay() const;

lldb/packages/Python/lldbsuite/test/expression_command/save_jit_objects/Makefile

@@ -0,0 +1,5 @@
+LEVEL = ../../make
+
+C_SOURCES := main.c
+
+include $(LEVEL)/Makefile.rules

lldb/packages/Python/lldbsuite/test/expression_command/save_jit_objects/TestSaveJITObjects.py

@@ -0,0 +1,57 @@
+"""
+Test that LLDB can emit JIT objects when the appropriate setting is enabled
+"""
+
+from __future__ import print_function
+
+import os
+import time
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+def enumerateJITFiles():
+    return [f for f in os.listdir(os.getcwd()) if f.startswith("jit")]
+    
+def countJITFiles():
+    return len(enumerateJITFiles())
+
+def cleanJITFiles():
+    for j in enumerateJITFiles():
+        os.remove(j)
+    return
+
+class SaveJITObjectsTestCase(TestBase):
+    mydir = TestBase.compute_mydir(__file__)
+
+    def test_save_jit_objects(self):
+        self.build()
+        src_file = "main.c"
+        src_file_spec = lldb.SBFileSpec(src_file)
+  
+        exe_path = os.path.join(os.getcwd(), "a.out")
+        target = self.dbg.CreateTarget(exe_path)
+
+        breakpoint = target.BreakpointCreateBySourceRegex(
+            "break", src_file_spec)
+
+        process = target.LaunchSimple(None, None,
+                                      self.get_process_working_directory())
+
+        thread = process.GetSelectedThread()
+        frame = thread.GetSelectedFrame()
+
+        cleanJITFiles()
+        frame.EvaluateExpression("(void*)malloc(0x1)")
+        self.assertTrue(countJITFiles() == 0,
+                        "No files emitted with save-jit-objects=false")
+
+        self.runCmd("settings set target.save-jit-objects true")
+        frame.EvaluateExpression("(void*)malloc(0x1)")
+        jit_files_count = countJITFiles()
+        cleanJITFiles()
+        self.assertTrue(jit_files_count != 0,
+                        "At least one file emitted with save-jit-objects=true")
+
+        process.Kill()

lldb/packages/Python/lldbsuite/test/expression_command/save_jit_objects/main.c

@@ -0,0 +1,14 @@
+//===-- main.c --------------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+int main (int argc, char const *argv[])
+{
+	const char* foo = "Hello world"; // break here
+    return 0;
+}

lldb/source/Expression/IRExecutionUnit.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/ExecutionEngine/ObjectCache.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
@@ -306,6 +307,32 @@ void IRExecutionUnit::GetRunnableInfo(Error &error, lldb::addr_t &func_addr,
     return;
   }
 
+  class ObjectDumper : public llvm::ObjectCache {
+  public:
+    void notifyObjectCompiled(const llvm::Module *module,
+                              llvm::MemoryBufferRef object) override {
+      int fd = 0;
+      llvm::SmallVector<char, 256> result_path;
+      std::string object_name_model =
+          "jit-object-" + module->getModuleIdentifier() + "-%%%.o";
+      (void)llvm::sys::fs::createUniqueFile(object_name_model, fd, result_path);
+      llvm::raw_fd_ostream fds(fd, true);
+      fds.write(object.getBufferStart(), object.getBufferSize());
+    }
+
+    std::unique_ptr<llvm::MemoryBuffer>
+    getObject(const llvm::Module *module) override {
+      // Return nothing - we're just abusing the object-cache mechanism to dump
+      // objects.
+      return nullptr;
+    }
+  };
+
+  if (process_sp->GetTarget().GetEnableSaveObjects()) {
+    m_object_cache_ap = llvm::make_unique<ObjectDumper>();
+    m_execution_engine_ap->setObjectCache(m_object_cache_ap.get());
+  }
+
   // Make sure we see all sections, including ones that don't have
   // relocations...
   m_execution_engine_ap->setProcessAllSections(true);

lldb/source/Target/Target.cpp

@@ -3246,6 +3246,8 @@ static PropertyDefinition g_properties[] = {
      nullptr, "Automatically apply fix-it hints to expressions."},
     {"notify-about-fixits", OptionValue::eTypeBoolean, false, true, nullptr,
      nullptr, "Print the fixed expression text."},
+    {"save-jit-objects", OptionValue::eTypeBoolean, false, false, nullptr,
+     nullptr, "Save intermediate object files generated by the LLVM JIT"},
     {"max-children-count", OptionValue::eTypeSInt64, false, 256, nullptr,
      nullptr, "Maximum number of children to expand in any level of depth."},
     {"max-string-summary-length", OptionValue::eTypeSInt64, false, 1024,
@@ -3370,6 +3372,7 @@ enum {
   ePropertyAutoImportClangModules,
   ePropertyAutoApplyFixIts,
   ePropertyNotifyAboutFixIts,
+  ePropertySaveObjects,
   ePropertyMaxChildrenCount,
   ePropertyMaxSummaryLength,
   ePropertyMaxMemReadSize,
@@ -3788,6 +3791,12 @@ bool TargetProperties::GetEnableNotifyAboutFixIts() const {
       nullptr, idx, g_properties[idx].default_uint_value != 0);
 }
 
+bool TargetProperties::GetEnableSaveObjects() const {
+  const uint32_t idx = ePropertySaveObjects;
+  return m_collection_sp->GetPropertyAtIndexAsBoolean(
+      nullptr, idx, g_properties[idx].default_uint_value != 0);
+}
+
 bool TargetProperties::GetEnableSyntheticValue() const {
   const uint32_t idx = ePropertyEnableSynthetic;
   return m_collection_sp->GetPropertyAtIndexAsBoolean(