[llvm-objdump] Add --build-id flag for debuginfod lookups without binary.

Adding a --build-id flag allows handling binaries that are referenced in
logs from remote systems, but that aren't necessarily present on the
local machine. These are fetched via debuginfod and handled as if they
were input filenames.

Reviewed By: jhenderson, MaskRay

Differential Revision: https://reviews.llvm.org/D133992

1 files changed, 25 insertions, 2 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 689aa0a..f7d6666d 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -2916,6 +2916,17 @@ static void parseIntArg(const llvm::opt::InputArgList &InputArgs, int ID,
   }
 }
 
+static object::BuildID parseBuildIDArg(const opt::Arg *A) {
+  StringRef V(A->getValue());
+  std::string Bytes;
+  if (!tryGetFromHex(V, Bytes))
+    reportCmdLineError(A->getSpelling() + ": expected a build ID, but got '" +
+                       V + "'");
+  ArrayRef<uint8_t> BuildID(reinterpret_cast<const uint8_t *>(Bytes.data()),
+                            Bytes.size());
+  return object::BuildID(BuildID.begin(), BuildID.end());
+}
+
 static void invalidArgValue(const opt::Arg *A) {
   reportCmdLineError("'" + StringRef(A->getValue()) +
                      "' is not a valid value for '" + A->getSpelling() + "'");
@@ -3084,6 +3095,17 @@ static void parseObjdumpOptions(const llvm::opt::InputArgList &InputArgs) {
     llvm::cl::ParseCommandLineOptions(2, Argv);
   }
 
+  // Look up any provided build IDs, then append them to the input filenames.
+  for (const opt::Arg *A : InputArgs.filtered(OBJDUMP_build_id)) {
+    object::BuildID BuildID = parseBuildIDArg(A);
+    Optional<std::string> Path = BIDFetcher->fetch(BuildID);
+    if (!Path) {
+      reportCmdLineError(A->getSpelling() + ": could not find build ID '" +
+                         A->getValue() + "'");
+    }
+    InputFilenames.push_back(std::move(*Path));
+  }
+
   // objdump defaults to a.out if no filenames specified.
   if (InputFilenames.empty())
     InputFilenames.push_back("a.out");
@@ -3153,8 +3175,9 @@ int main(int argc, char **argv) {
 
   // Initialize debuginfod.
   const bool ShouldUseDebuginfodByDefault =
-      HTTPClient::isAvailable() &&
-      !ExitOnErr(getDefaultDebuginfodUrls()).empty();
+      InputArgs.hasArg(OBJDUMP_build_id) ||
+      (HTTPClient::isAvailable() &&
+       !ExitOnErr(getDefaultDebuginfodUrls()).empty());
   std::vector<std::string> DebugFileDirectories =
       InputArgs.getAllArgValues(OBJDUMP_debug_file_directory);
   if (InputArgs.hasFlag(OBJDUMP_debuginfod, OBJDUMP_no_debuginfod,