[DWARF parser] Fix nasty memory corruption in .dwo files handling.

Forge a test case where llvm-symbolizer has to use external .dwo
file to produce the inlining information.

llvm-svn: 217270

lib/DebugInfo/DWARFUnit.cpp

@@ -235,11 +235,14 @@ size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
   return DieArray.size();
 }
 
-DWARFUnit::DWOHolder::DWOHolder(std::unique_ptr<object::ObjectFile> DWOFile)
-    : DWOFile(std::move(DWOFile)),
-      DWOContext(
-          cast<DWARFContext>(DIContext::getDWARFContext(*this->DWOFile))),
-      DWOU(nullptr) {
+DWARFUnit::DWOHolder::DWOHolder(StringRef DWOPath)
+    : DWOFile(), DWOContext(), DWOU(nullptr) {
+  auto Obj = object::ObjectFile::createObjectFile(DWOPath);
+  if (!Obj)
+    return;
+  DWOFile = std::move(Obj.get());
+  DWOContext.reset(
+      cast<DWARFContext>(DIContext::getDWARFContext(*DWOFile.getBinary())));
   if (DWOContext->getNumDWOCompileUnits() > 0)
     DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
 }
@@ -261,12 +264,7 @@ bool DWARFUnit::parseDWO() {
     sys::path::append(AbsolutePath, CompilationDir);
   }
   sys::path::append(AbsolutePath, DWOFileName);
-  ErrorOr<object::OwningBinary<object::ObjectFile>> DWOFile =
-      object::ObjectFile::createObjectFile(AbsolutePath);
-  if (!DWOFile)
-    return false;
-  // Reset DWOHolder.
-  DWO = llvm::make_unique<DWOHolder>(std::move(DWOFile->getBinary()));
+  DWO = llvm::make_unique<DWOHolder>(AbsolutePath);
   DWARFUnit *DWOCU = DWO->getUnit();
   // Verify that compile unit in .dwo file is valid.
   if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {

lib/DebugInfo/DWARFUnit.h

@@ -51,11 +51,11 @@ class DWARFUnit {
   std::vector<DWARFDebugInfoEntryMinimal> DieArray;
 
   class DWOHolder {
-    std::unique_ptr<object::ObjectFile> DWOFile;
+    object::OwningBinary<object::ObjectFile> DWOFile;
     std::unique_ptr<DWARFContext> DWOContext;
     DWARFUnit *DWOU;
   public:
-    DWOHolder(std::unique_ptr<object::ObjectFile> DWOFile);
+    DWOHolder(StringRef DWOPath);
     DWARFUnit *getUnit() const { return DWOU; }
   };
   std::unique_ptr<DWOHolder> DWO;

test/DebugInfo/Inputs/split-dwarf-test.cc

@@ -0,0 +1,17 @@
+int foo(int a) {
+  return a + 1;
+}
+
+int main(int argc, char *argv[]) {
+  return foo(argc);
+}
+
+// Build instructions:
+// 1) clang++ -### -O2 -gsplit-dwarf.cc split-dwarf-test.cc -o split-dwarf-test
+// 2) Replace the value "-fdebug-compilation-dir" flag to "Output"
+//      (this is the temp directory used by lit).
+// 3) Manually run clang-cc1, objcopy and ld invocations.
+// 4) Copy the binary and .dwo file to the Inputs directory. Make sure the
+//    .dwo file will be available for symbolizer (use test RUN-lines to copy
+//    the .dwo file to a directory
+//    <execution_directory>/<directory_provided_in_fdebug_compilation_dir>.

test/DebugInfo/llvm-symbolizer.test

@@ -19,10 +19,15 @@ RUN: echo "%p/Inputs/macho-universal:x86_64 0x100000f05" >> %t.input
 RUN: echo "%p/Inputs/llvm-symbolizer-dwo-test 0x400514" >> %t.input
 RUN: echo "%p/Inputs/fission-ranges.elf-x86_64 0x720" >> %t.input
 RUN: echo "%p/Inputs/arange-overlap.elf-x86_64 0x714" >> %t.input
+RUN: cp %p/Inputs/split-dwarf-test.dwo %T
+RUN: echo "%p/Inputs/split-dwarf-test 0x4004d0" >> %t.input
+RUN: echo "%p/Inputs/split-dwarf-test 0x4004c0" >> %t.input
 
 RUN: llvm-symbolizer --functions=linkage --inlining --demangle=false \
 RUN:    --default-arch=i386 < %t.input | FileCheck %s
 
+REQUIRES: shell
+
 CHECK:       main
 CHECK-NEXT: /tmp/dbginfo{{[/\\]}}dwarfdump-test.cc:16
 
@@ -98,6 +103,14 @@ CHECK-NEXT: {{.*}}fission-ranges.cc:6
 CHECK: _ZN1S3bazEv
 CHECK-NEXT: {{.*}}arange-overlap.cc:6
 
+CHECK: _Z3fooi
+CHECK-NEXT: {{.*}}split-dwarf-test.cc
+CHECK-NEXT: main
+CHECK-NEXT: {{.*}}split-dwarf-test.cc
+
+CHECK: _Z3fooi
+CHECK-NEXT: {{.*}}split-dwarf-test.cc
+
 RUN: echo "unexisting-file 0x1234" > %t.input2
 RUN: llvm-symbolizer < %t.input2