Implement GDB integration for source level debugging of code JITed using

the MCJIT execution engine.

The GDB JIT debugging integration support works by registering a loaded
object image with a pre-defined function that GDB will monitor if GDB
is attached. GDB integration support is implemented for ELF only at this
time. This integration requires GDB version 7.0 or newer.

Patch by Andy Kaylor!

 

llvm-svn: 154868

1 files changed, 26 insertions, 11 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 63cec1aca3b..1b1840ae066 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -59,11 +59,17 @@ void RuntimeDyldImpl::mapSectionAddress(void *LocalAddress,
   llvm_unreachable("Attempting to remap address of unknown section!");
 }
 
+// Subclasses can implement this method to create specialized image instances
+// The caller owns the the pointer that is returned.
+ObjectImage *RuntimeDyldImpl::createObjectImage(const MemoryBuffer *InputBuffer) {
+  ObjectFile *ObjFile = ObjectFile::createObjectFile(const_cast<MemoryBuffer*>
+                                                                 (InputBuffer));
+  ObjectImage *Obj = new ObjectImage(ObjFile);
+  return Obj;
+}
+
 bool RuntimeDyldImpl::loadObject(const MemoryBuffer *InputBuffer) {
-  // FIXME: ObjectFile don't modify MemoryBuffer.
-  //        It should use const MemoryBuffer as parameter.
-  OwningPtr<ObjectFile> obj(ObjectFile::createObjectFile(
-                                       const_cast<MemoryBuffer*>(InputBuffer)));
+  OwningPtr<ObjectImage> obj(createObjectImage(InputBuffer));
   if (!obj)
     report_fatal_error("Unable to create object image from memory buffer!");
 
@@ -110,7 +116,8 @@ bool RuntimeDyldImpl::loadObject(const MemoryBuffer *InputBuffer) {
                                 (uintptr_t)FileOffset;
         uintptr_t SectOffset = (uintptr_t)(SymPtr - (const uint8_t*)sData.begin());
         unsigned SectionID =
-          findOrEmitSection(*si,
+          findOrEmitSection(*obj,
+                            *si,
                             SymType == object::SymbolRef::ST_Function,
                             LocalSections);
         bool isGlobal = flags & SymbolRef::SF_Global;
@@ -128,7 +135,7 @@ bool RuntimeDyldImpl::loadObject(const MemoryBuffer *InputBuffer) {
 
   // Allocate common symbols
   if (CommonSize != 0)
-    emitCommonSymbols(CommonSymbols, CommonSize, LocalSymbols);
+    emitCommonSymbols(*obj, CommonSymbols, CommonSize, LocalSymbols);
 
   // Parse and proccess relocations
   DEBUG(dbgs() << "Parse relocations:\n");
@@ -145,7 +152,7 @@ bool RuntimeDyldImpl::loadObject(const MemoryBuffer *InputBuffer) {
 
       // If it's first relocation in this section, find its SectionID
       if (isFirstRelocation) {
-        SectionID = findOrEmitSection(*si, true, LocalSections);
+        SectionID = findOrEmitSection(*obj, *si, true, LocalSections);
         DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
         isFirstRelocation = false;
       }
@@ -164,10 +171,14 @@ bool RuntimeDyldImpl::loadObject(const MemoryBuffer *InputBuffer) {
       processRelocationRef(RI, *obj, LocalSections, LocalSymbols, Stubs);
     }
   }
+
+  handleObjectLoaded(obj.take());
+
   return false;
 }
 
-unsigned RuntimeDyldImpl::emitCommonSymbols(const CommonSymbolMap &Map,
+unsigned RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
+                                            const CommonSymbolMap &Map,
                                             uint64_t TotalSize,
                                             LocalSymbolMap &LocalSymbols) {
   // Allocate memory for the section
@@ -191,6 +202,7 @@ unsigned RuntimeDyldImpl::emitCommonSymbols(const CommonSymbolMap &Map,
     uint64_t Size = it->second;
     StringRef Name;
     it->first.getName(Name);
+    Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
     LocalSymbols[Name.data()] = SymbolLoc(SectionID, Offset);
     Offset += Size;
     Addr += Size;
@@ -199,7 +211,8 @@ unsigned RuntimeDyldImpl::emitCommonSymbols(const CommonSymbolMap &Map,
   return SectionID;
 }
 
-unsigned RuntimeDyldImpl::emitSection(const SectionRef &Section,
+unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
+                                      const SectionRef &Section,
                                       bool IsCode) {
 
   unsigned StubBufSize = 0,
@@ -257,6 +270,7 @@ unsigned RuntimeDyldImpl::emitSection(const SectionRef &Section,
                  << " StubBufSize: " << StubBufSize
                  << " Allocate: " << Allocate
                  << "\n");
+    Obj.updateSectionAddress(Section, (uint64_t)Addr);
   }
   else {
     // Even if we didn't load the section, we need to record an entry for it
@@ -277,7 +291,8 @@ unsigned RuntimeDyldImpl::emitSection(const SectionRef &Section,
   return SectionID;
 }
 
-unsigned RuntimeDyldImpl::findOrEmitSection(const SectionRef &Section,
+unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
+                                            const SectionRef &Section,
                                             bool IsCode,
                                             ObjSectionToIDMap &LocalSections) {
 
@@ -286,7 +301,7 @@ unsigned RuntimeDyldImpl::findOrEmitSection(const SectionRef &Section,
   if (i != LocalSections.end())
     SectionID = i->second;
   else {
-    SectionID = emitSection(Section, IsCode);
+    SectionID = emitSection(Obj, Section, IsCode);
     LocalSections[Section] = SectionID;
   }
   return SectionID;