[llvm] 00e436f - [llvm-symbolizer] Support debug file lookup using build ID
Petr Hosek via llvm-commits
llvm-commits at lists.llvm.org
Wed Dec 4 15:08:39 PST 2019
Author: Petr Hosek
Date: 2019-12-04T15:07:56-08:00
New Revision: 00e436f1307f506681782d26f4d3b9e98feada5a
URL: https://github.com/llvm/llvm-project/commit/00e436f1307f506681782d26f4d3b9e98feada5a
DIFF: https://github.com/llvm/llvm-project/commit/00e436f1307f506681782d26f4d3b9e98feada5a.diff
LOG: [llvm-symbolizer] Support debug file lookup using build ID
Build ID is a protocol for looking up debug files that's already
supported by various tools including debuggers. For example, when
locating debug files, gdb would check the following directories:
- /usr/lib/debug/.build-id/ab/cdef1234.debug
- /usr/bin/ls.debug
- /usr/bin/.debug/ls.debug
- /usr/lib/debug/usr/bin/ls.debug
llvm-symbolizer currently consults all of these except for build ID
based one. This patch implements support for build ID lookup. The
set of debug directories to search is specified by the new option:
--debug-file-directory, whose name matches the debug-file-directory
variable used by gdb for the same purpose.
Differential Revision: https://reviews.llvm.org/D70759
Added:
llvm/test/DebugInfo/Inputs/.build-id/ab/b50d82b6bdc861.debug
llvm/test/DebugInfo/symbolize-build-id.test
Modified:
llvm/include/llvm/DebugInfo/Symbolize/Symbolize.h
llvm/lib/DebugInfo/Symbolize/Symbolize.cpp
llvm/tools/llvm-symbolizer/llvm-symbolizer.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/DebugInfo/Symbolize/Symbolize.h b/llvm/include/llvm/DebugInfo/Symbolize/Symbolize.h
index 11599fc1797d..8bfa5432b811 100644
--- a/llvm/include/llvm/DebugInfo/Symbolize/Symbolize.h
+++ b/llvm/include/llvm/DebugInfo/Symbolize/Symbolize.h
@@ -16,6 +16,7 @@
#include "llvm/DebugInfo/Symbolize/SymbolizableModule.h"
#include "llvm/Object/Binary.h"
#include "llvm/Object/ObjectFile.h"
+#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Support/Error.h"
#include <algorithm>
#include <cstdint>
@@ -44,6 +45,7 @@ class LLVMSymbolizer {
std::vector<std::string> DsymHints;
std::string FallbackDebugPath;
std::string DWPName;
+ std::vector<std::string> DebugFileDirectory;
};
LLVMSymbolizer() = default;
@@ -98,6 +100,9 @@ class LLVMSymbolizer {
ObjectFile *lookUpDebuglinkObject(const std::string &Path,
const ObjectFile *Obj,
const std::string &ArchName);
+ ObjectFile *lookUpBuildIDObject(const std::string &Path,
+ const ELFObjectFileBase *Obj,
+ const std::string &ArchName);
/// Returns pair of pointers to object and debug object.
Expected<ObjectPair> getOrCreateObjectPair(const std::string &Path,
diff --git a/llvm/lib/DebugInfo/Symbolize/Symbolize.cpp b/llvm/lib/DebugInfo/Symbolize/Symbolize.cpp
index be79d9e637c1..cb076aed3aac 100644
--- a/llvm/lib/DebugInfo/Symbolize/Symbolize.cpp
+++ b/llvm/lib/DebugInfo/Symbolize/Symbolize.cpp
@@ -284,6 +284,79 @@ bool darwinDsymMatchesBinary(const MachOObjectFile *DbgObj,
return !memcmp(dbg_uuid.data(), bin_uuid.data(), dbg_uuid.size());
}
+template <typename ELFT>
+Optional<ArrayRef<uint8_t>> getBuildID(const ELFFile<ELFT> *Obj) {
+ if (!Obj)
+ return {};
+ auto PhdrsOrErr = Obj->program_headers();
+ if (!PhdrsOrErr) {
+ consumeError(PhdrsOrErr.takeError());
+ return {};
+ }
+ for (const auto &P : *PhdrsOrErr) {
+ if (P.p_type != ELF::PT_NOTE)
+ continue;
+ Error Err = Error::success();
+ for (const auto &N : Obj->notes(P, Err))
+ if (N.getType() == ELF::NT_GNU_BUILD_ID && N.getName() == ELF::ELF_NOTE_GNU)
+ return N.getDesc();
+ }
+ return {};
+}
+
+Optional<ArrayRef<uint8_t>> getBuildID(const ELFObjectFileBase *Obj) {
+ Optional<ArrayRef<uint8_t>> BuildID;
+ if (auto *O = dyn_cast<ELFObjectFile<ELF32LE>>(Obj))
+ BuildID = getBuildID(O->getELFFile());
+ else if (auto *O = dyn_cast<ELFObjectFile<ELF32BE>>(Obj))
+ BuildID = getBuildID(O->getELFFile());
+ else if (auto *O = dyn_cast<ELFObjectFile<ELF64LE>>(Obj))
+ BuildID = getBuildID(O->getELFFile());
+ else if (auto *O = dyn_cast<ELFObjectFile<ELF64BE>>(Obj))
+ BuildID = getBuildID(O->getELFFile());
+ else
+ llvm_unreachable("unsupported file format");
+ return BuildID;
+}
+
+bool findDebugBinary(const std::vector<std::string> &DebugFileDirectory,
+ const ArrayRef<uint8_t> BuildID,
+ std::string &Result) {
+ auto getDebugPath = [&](StringRef Directory) {
+ SmallString<128> Path{Directory};
+ sys::path::append(Path, ".build-id",
+ llvm::toHex(BuildID[0], /*LowerCase=*/true),
+ llvm::toHex(BuildID.slice(1), /*LowerCase=*/true));
+ Path += ".debug";
+ return Path;
+ };
+ if (DebugFileDirectory.empty()) {
+ SmallString<128> Path = getDebugPath(
+#if defined(__NetBSD__)
+ // Try /usr/libdata/debug/.build-id/../...
+ "/usr/libdata/debug"
+#else
+ // Try /usr/lib/debug/.build-id/../...
+ "/usr/lib/debug"
+#endif
+ );
+ if (llvm::sys::fs::exists(Path)) {
+ Result = Path.str();
+ return true;
+ }
+ } else {
+ for (const auto &Directory : DebugFileDirectory) {
+ // Try <debug-file-directory>/.build-id/../...
+ SmallString<128> Path = getDebugPath(Directory);
+ if (llvm::sys::fs::exists(Path)) {
+ Result = Path.str();
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
} // end anonymous namespace
ObjectFile *LLVMSymbolizer::lookUpDsymFile(const std::string &ExePath,
@@ -335,6 +408,25 @@ ObjectFile *LLVMSymbolizer::lookUpDebuglinkObject(const std::string &Path,
return DbgObjOrErr.get();
}
+ObjectFile *LLVMSymbolizer::lookUpBuildIDObject(const std::string &Path,
+ const ELFObjectFileBase *Obj,
+ const std::string &ArchName) {
+ auto BuildID = getBuildID(Obj);
+ if (!BuildID)
+ return nullptr;
+ if (BuildID->size() < 2)
+ return nullptr;
+ std::string DebugBinaryPath;
+ if (!findDebugBinary(Opts.DebugFileDirectory, *BuildID, DebugBinaryPath))
+ return nullptr;
+ auto DbgObjOrErr = getOrCreateObject(DebugBinaryPath, ArchName);
+ if (!DbgObjOrErr) {
+ consumeError(DbgObjOrErr.takeError());
+ return nullptr;
+ }
+ return DbgObjOrErr.get();
+}
+
Expected<LLVMSymbolizer::ObjectPair>
LLVMSymbolizer::getOrCreateObjectPair(const std::string &Path,
const std::string &ArchName) {
@@ -355,6 +447,8 @@ LLVMSymbolizer::getOrCreateObjectPair(const std::string &Path,
if (auto MachObj = dyn_cast<const MachOObjectFile>(Obj))
DbgObj = lookUpDsymFile(Path, MachObj, ArchName);
+ else if (auto ELFObj = dyn_cast<const ELFObjectFileBase>(Obj))
+ DbgObj = lookUpBuildIDObject(Path, ELFObj, ArchName);
if (!DbgObj)
DbgObj = lookUpDebuglinkObject(Path, Obj, ArchName);
if (!DbgObj)
diff --git a/llvm/test/DebugInfo/Inputs/.build-id/ab/b50d82b6bdc861.debug b/llvm/test/DebugInfo/Inputs/.build-id/ab/b50d82b6bdc861.debug
new file mode 100755
index 000000000000..5eafa358a9c6
Binary files /dev/null and b/llvm/test/DebugInfo/Inputs/.build-id/ab/b50d82b6bdc861.debug
diff er
diff --git a/llvm/test/DebugInfo/symbolize-build-id.test b/llvm/test/DebugInfo/symbolize-build-id.test
new file mode 100644
index 000000000000..40221ae9e057
--- /dev/null
+++ b/llvm/test/DebugInfo/symbolize-build-id.test
@@ -0,0 +1,28 @@
+# RUN: yaml2obj %s -o %t
+
+# RUN: llvm-symbolizer --debug-file-directory=/non-existent --obj=%t 0x20112f | FileCheck --check-prefix=UNKNOWN %s
+
+# UNKNOWN: ??
+# UNKNOWN-NEXT: ??:0:0
+
+# RUN: llvm-symbolizer --debug-file-directory=%p/Inputs --obj=%t 0x20112f | FileCheck --check-prefix=FOUND %s
+
+# FOUND: main
+# FOUND-NEXT: /tmp/dbginfo{{[/\\]}}dwarfdump-test.cc:16
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_EXEC
+ Machine: EM_X86_64
+Sections:
+ - Name: .note.gnu.build-id
+ Type: SHT_NOTE
+ Flags: [ SHF_ALLOC ]
+ Content: 040000000800000003000000474e5500abb50d82b6bdc861
+ProgramHeaders:
+ - Type: PT_NOTE
+ Flags: [ PF_R ]
+ Sections:
+ - Section: .note.gnu.build-id
diff --git a/llvm/tools/llvm-symbolizer/llvm-symbolizer.cpp b/llvm/tools/llvm-symbolizer/llvm-symbolizer.cpp
index 54ce87d47979..c9bc0309a654 100644
--- a/llvm/tools/llvm-symbolizer/llvm-symbolizer.cpp
+++ b/llvm/tools/llvm-symbolizer/llvm-symbolizer.cpp
@@ -150,6 +150,12 @@ static cl::opt<std::string>
ClFallbackDebugPath("fallback-debug-path", cl::init(""),
cl::desc("Fallback path for debug binaries."));
+static cl::list<std::string>
+ ClDebugFileDirectory("debug-file-directory", cl::ZeroOrMore,
+ cl::value_desc("dir"),
+ cl::desc("Path to directory where to look for debug "
+ "files."));
+
static cl::opt<DIPrinter::OutputStyle>
ClOutputStyle("output-style", cl::init(DIPrinter::OutputStyle::LLVM),
cl::desc("Specify print style"),
@@ -299,6 +305,7 @@ int main(int argc, char **argv) {
Opts.DefaultArch = ClDefaultArch;
Opts.FallbackDebugPath = ClFallbackDebugPath;
Opts.DWPName = ClDwpName;
+ Opts.DebugFileDirectory = ClDebugFileDirectory;
for (const auto &hint : ClDsymHint) {
if (sys::path::extension(hint) == ".dSYM") {
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