From 7b9c96a5716a789ac64ccd9886d01a974584aca3 Mon Sep 17 00:00:00 2001
From: Iain Sandoe <iain@sandoe.co.uk>
Date: Sun, 2 Sep 2018 20:20:29 +0100
Subject: [PATCH] [dsymutil, WIP, DEBUG] work on GCC LTO problem

---
 llvm/tools/dsymutil/DebugMap.cpp            |  7 ++++
 llvm/tools/dsymutil/DwarfLinker.cpp         |  7 +++-
 llvm/tools/dsymutil/MachODebugMapParser.cpp | 38 +++++++++++++++++++--
 3 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/llvm/tools/dsymutil/DebugMap.cpp b/llvm/tools/dsymutil/DebugMap.cpp
index 26137773a4e..302bb0f8bc7 100644
--- a/llvm/tools/dsymutil/DebugMap.cpp
+++ b/llvm/tools/dsymutil/DebugMap.cpp
@@ -33,6 +33,8 @@
 #include <utility>
 #include <vector>
 
+#include "llvm/Support/Debug.h"
+
 namespace llvm {
 
 namespace dsymutil {
@@ -92,9 +94,14 @@ DebugMap::addDebugMapObject(StringRef ObjectFilePath,
 
 const DebugMapObject::DebugMapEntry *
 DebugMapObject::lookupSymbol(StringRef SymbolName) const {
+dbgs () << "looking for " << SymbolName;
   StringMap<SymbolMapping>::const_iterator Sym = Symbols.find(SymbolName);
   if (Sym == Symbols.end())
+    {
+      dbgs () << " NO\n";
     return nullptr;
+    }
+  dbgs () << " OK\n";
   return &*Sym;
 }
 
diff --git a/llvm/tools/dsymutil/DwarfLinker.cpp b/llvm/tools/dsymutil/DwarfLinker.cpp
index 430e8e063e3..a9e8a9a053e 100644
--- a/llvm/tools/dsymutil/DwarfLinker.cpp
+++ b/llvm/tools/dsymutil/DwarfLinker.cpp
@@ -973,7 +973,12 @@ unsigned DwarfLinker::DIECloner::cloneDieReferenceAttribute(
   }
 
   if (!RefInfo.Clone) {
-    assert(Ref > InputDIE.getOffset());
+//    assert(Ref > InputDIE.getOffset());
+   if (Ref <= InputDIE.getOffset()) {
+dbgs() << format(" Ref : %u ID offst : %u ", Ref, InputDIE.getOffset());
+dbgs() << "inpdie: "; InputDIE.dump();
+dbgs() << "refdie: ";RefDie.dump();
+   }
     // We haven't cloned this DIE yet. Just create an empty one and
     // store it. It'll get really cloned when we process it.
     RefInfo.Clone = DIE::get(DIEAlloc, dwarf::Tag(RefDie.getTag()));
diff --git a/llvm/tools/dsymutil/MachODebugMapParser.cpp b/llvm/tools/dsymutil/MachODebugMapParser.cpp
index 48155b40204..edcf92d22f5 100644
--- a/llvm/tools/dsymutil/MachODebugMapParser.cpp
+++ b/llvm/tools/dsymutil/MachODebugMapParser.cpp
@@ -15,6 +15,8 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Format.h"
 
 namespace {
 using namespace llvm;
@@ -151,6 +153,7 @@ void MachODebugMapParser::switchToNewDebugMapObject(
 
   CurrentDebugMapObject =
       &Result->addDebugMapObject(Path, Timestamp, MachO::N_OSO);
+dbgs () << " loading symbols for : " + Path.str() + "\n";
   loadCurrentObjectFileSymbols(*Object);
 }
 
@@ -454,6 +457,7 @@ void MachODebugMapParser::loadCurrentObjectFileSymbols(
     uint64_t Addr = Sym.getValue();
     Expected<StringRef> Name = Sym.getName();
     if (!Name) {
+dbgs() << " <empty name>\n";
       // TODO: Actually report errors helpfully.
       consumeError(Name.takeError());
       continue;
@@ -466,10 +470,40 @@ void MachODebugMapParser::loadCurrentObjectFileSymbols(
     // relocations will use the symbol itself, and won't need an
     // object file address. The object file address field is optional
     // in the DebugMap, leave it unassigned for these symbols.
-    if (Sym.getFlags() & (SymbolRef::SF_Absolute | SymbolRef::SF_Common))
+    if (Sym.getFlags() & (SymbolRef::SF_Absolute | SymbolRef::SF_Common)) {
       CurrentObjectAddresses[*Name] = None;
-    else
+      continue;
+    } else
       CurrentObjectAddresses[*Name] = Addr;
+    Expected<SymbolRef::Type> TypeOrErr = Sym.getType();
+    if (!TypeOrErr) {
+dbgs() << " bade type?\n";
+      // TODO: Actually report errors helpfully.
+      consumeError(TypeOrErr.takeError());
+      continue;
+    }
+    SymbolRef::Type Type = *TypeOrErr;
+    if (Type == SymbolRef::ST_Debug || Type == SymbolRef::ST_Unknown)
+      continue;
+    uint8_t SymType =
+        Obj.getSymbolTableEntry(Sym.getRawDataRefImpl()).n_type;
+    if (!(SymType & (MachO::N_EXT | MachO::N_PEXT)))
+      continue;
+    Expected<section_iterator> SectionOrErr = Sym.getSection();
+    if (!SectionOrErr) {
+      // TODO: Actually report errors helpfully.
+      consumeError(SectionOrErr.takeError());
+      continue;
+    }
+    section_iterator Section = *SectionOrErr;
+    //if (!Section->isDebug()) how to do this?
+    //  continue;
+    StringRef SectName;
+    Section->getName(SectName);
+    if (SectName == "__debug_info") {
+dbgs() << *Name << " " << SectName << format(" 0x%llx\n", Addr);
+      CurrentDebugMapObject->addSymbol(*Name, Addr, 0, 0);
+    }
   }
 }