[llvm-dwp] Implement -e option

The binutils utility dwp has an option "-e" 
https://gcc.gnu.org/wiki/DebugFissionDWP
to specify an executable/library to get the list 
of *.dwo files from it. This option is particularly useful when 
someone runs the tool manually outside of a build system.
This diff adds an implementation of "-e" to llvm-dwp.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D37371

llvm-svn: 312409

test/tools/llvm-dwp/X86/dwos_list_from_exec_simple.test

@@ -0,0 +1,97 @@
+REQUIRES: shell
+
+RUN: rm -rf %t
+RUN: mkdir %t
+RUN: cd %t
+RUN: cp %p/../Inputs/dwos_list_from_exec/a.dwo a.dwo
+RUN: cp %p/../Inputs/dwos_list_from_exec/b.dwo b.dwo
+RUN: cp %p/../Inputs/dwos_list_from_exec/c.dwo c.dwo
+RUN: cp %p/../Inputs/dwos_list_from_exec/d.dwo d.dwo
+RUN: cp %p/../Inputs/dwos_list_from_exec/e.dwo e.dwo
+RUN: cp %p/../Inputs/dwos_list_from_exec/main main
+RUN: cp %p/../Inputs/dwos_list_from_exec/libd.so libd.so
+RUN: llvm-dwp c.dwo e.dwo -e main -e libd.so -o pkg.dwp
+RUN: llvm-dwarfdump pkg.dwp | FileCheck %s
+
+Build commands for the test binaries:
+
+clang++ -Xclang -fdebug-compilation-dir -Xclang "./" -g -O0 -gsplit-dwarf a.cpp b.cpp -o main
+clang++ -g -O0 -gsplit-dwarf -c c.cpp -o c.o
+clang++ -Xclang -fdebug-compilation-dir -Xclang "./" -g -O0 -gsplit-dwarf -fPIC -shared d.cpp -o libd.so
+clang++ -g -O0 -gsplit-dwarf -c e.cpp -o e.o
+
+sources:
+a.cpp:
+  void a() {}
+
+b.cpp:
+  void b() {}
+  int main() {
+     return 0;
+  }
+
+c.cpp:
+  void c() {}
+
+d.cpp:
+  void d() {}
+
+e.cpp:
+  void e() {}
+
+CHECK-LABEL: .debug_abbrev.dwo contents:
+
+CHECK-LABEL: Abbrev table for offset:
+CHECK: DW_TAG_compile_unit
+CHECK: DW_TAG_subprogram
+
+CHECK-LABEL: Abbrev table for offset:
+CHECK: DW_TAG_compile_unit
+CHECK: DW_TAG_subprogram
+
+CHECK-LABEL: Abbrev table for offset:
+CHECK: DW_TAG_compile_unit
+CHECK: DW_TAG_subprogram
+
+CHECK-LABEL: Abbrev table for offset:
+CHECK: DW_TAG_compile_unit
+CHECK: DW_TAG_subprogram
+
+CHECK-LABEL: Abbrev table for offset:
+CHECK: DW_TAG_compile_unit
+CHECK: DW_TAG_subprogram
+
+CHECK: .debug_info.dwo contents:
+CHECK: [[AOFF:0x[0-9a-f]*]]:
+
+CHECK-LABEL: Compile Unit: length = {{.*}} version = 0x0004
+CHECK: DW_TAG_compile_unit
+CHECK:   DW_AT_name {{.*}} "c.cpp"
+CHECK:   DW_TAG_subprogram
+CHECK:     DW_AT_name {{.*}} "c"
+
+CHECK-LABEL: Compile Unit: length = {{.*}} version = 0x0004
+CHECK: DW_TAG_compile_unit
+CHECK:   DW_AT_name {{.*}} "e.cpp"
+CHECK:   DW_TAG_subprogram
+CHECK:     DW_AT_name {{.*}} "e"
+
+CHECK-LABEL: Compile Unit: length = {{.*}} version = 0x0004
+CHECK: DW_TAG_compile_unit
+CHECK:   DW_AT_name {{.*}} "a.cpp"
+CHECK:   DW_TAG_subprogram
+CHECK:     DW_AT_name {{.*}} "a"
+
+CHECK-LABEL: Compile Unit: length = {{.*}} version = 0x0004
+CHECK: DW_TAG_compile_unit
+CHECK:   DW_AT_name {{.*}} "b.cpp"
+CHECK:   DW_TAG_subprogram
+CHECK:     DW_AT_name {{.*}} "b"
+CHECK:   DW_TAG_subprogram
+CHECK:     DW_AT_name {{.*}} "main"
+
+CHECK-LABEL: Compile Unit: length = {{.*}} version = 0x0004
+CHECK: DW_TAG_compile_unit
+CHECK:   DW_AT_name {{.*}} "d.cpp"
+CHECK:   DW_TAG_subprogram
+CHECK:     DW_AT_name {{.*}} "d"

tools/llvm-dwp/llvm-dwp.cpp

@@ -17,6 +17,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
 #include "llvm/MC/MCAsmInfo.h"
@@ -36,6 +37,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Options.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/raw_ostream.h"
@@ -49,9 +51,14 @@ using namespace llvm::object;
 using namespace cl;
 
 OptionCategory DwpCategory("Specific Options");
-static list<std::string> InputFiles(Positional, OneOrMore,
+static list<std::string> InputFiles(Positional, ZeroOrMore,
                                     desc("<input files>"), cat(DwpCategory));
 
+static list<std::string> ExecFilenames(
+    "e", ZeroOrMore,
+    desc("Specify the executable/library files to get the list of *.dwo from"),
+    value_desc("filename"), cat(DwpCategory));
+
 static opt<std::string> OutputFilename(Required, "o",
                                        desc("Specify the output file."),
                                        value_desc("filename"),
@@ -463,6 +470,35 @@ buildDuplicateError(const std::pair<uint64_t, UnitIndexEntry> &PrevE,
       " and " + buildDWODescription(ID.Name, DWPName, ID.DWOName));
 }
 
+static Expected<SmallVector<std::string, 16>>
+getDWOFilenames(StringRef ExecFilename) {
+  auto ErrOrObj = object::ObjectFile::createObjectFile(ExecFilename);
+  if (!ErrOrObj)
+    return ErrOrObj.takeError();
+
+  const ObjectFile &Obj = *ErrOrObj.get().getBinary();
+  std::unique_ptr<DWARFContext> DWARFCtx = DWARFContext::create(Obj);
+
+  SmallVector<std::string, 16> DWOPaths;
+  for (const auto &CU : DWARFCtx->compile_units()) {
+    const DWARFDie &Die = CU->getUnitDIE();
+    std::string DWOName = dwarf::toString(
+        Die.find({dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}), "");
+    if (DWOName.empty())
+      continue;
+    std::string DWOCompDir =
+        dwarf::toString(Die.find(dwarf::DW_AT_comp_dir), "");
+    if (!DWOCompDir.empty()) {
+      SmallString<16> DWOPath;
+      sys::path::append(DWOPath, DWOCompDir, DWOName);
+      DWOPaths.emplace_back(DWOPath.data(), DWOPath.size());
+    } else {
+      DWOPaths.push_back(std::move(DWOName));
+    }
+  }
+  return std::move(DWOPaths);
+}
+
 static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
   const auto &MCOFI = *Out.getContext().getObjectFileInfo();
   MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
@@ -676,7 +712,19 @@ int main(int argc, char **argv) {
   if (!MS)
     return error("no object streamer for target " + TripleName, Context);
 
-  if (auto Err = write(*MS, InputFiles)) {
+  std::vector<std::string> DWOFilenames = InputFiles;
+  for (const auto &ExecFilename : ExecFilenames) {
+    auto DWOs = getDWOFilenames(ExecFilename);
+    if (!DWOs) {
+      logAllUnhandledErrors(DWOs.takeError(), errs(), "error: ");
+      return 1;
+    }
+    DWOFilenames.insert(DWOFilenames.end(),
+                        std::make_move_iterator(DWOs->begin()),
+                        std::make_move_iterator(DWOs->end()));
+  }
+
+  if (auto Err = write(*MS, DWOFilenames)) {
     logAllUnhandledErrors(std::move(Err), errs(), "error: ");
     return 1;
   }