[PATCH] D55943: [RuntimeDyld] load all non-relocation sections with ProcessAllSections

[Yonghong Song via Phabricator via llvm-commits]

yonghong-song created this revision.
yonghong-song added reviewers: lhames, labath.
Herald added subscribers: llvm-commits, aprantl.

This commit tried to address the following use case.

  . bcc (https://github.com/iovisor/bcc) utilizes llvm JIT to
    compile for BTF target.
  . with -g, .BTF and .BTF.ext sections (BPF debug info)
    will be generated by LLVM.
  . .BTF does not have relocations and .BTF.ext has some
    relocations.
  . With ProcessAllSections, .BTF.ext is loaded by JIT dynamic linker
    and is available to application. But .BTF is not loaded.

The bcc application needs to both .BTF.ext and .BTF for debugging
purpose. Since .BTF is not loaded, this patch addressed this issue

  by iterating over all sections and loading any missing
  non-relocation sections, after symbol/relocation processing
  in loadObjectImpl().


Repository:
  rL LLVM

https://reviews.llvm.org/D55943

Files:
  lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp


Index: lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
===================================================================
--- lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -382,6 +382,29 @@
       Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
   }
 
+  // Process remaining sections
+  if (ProcessAllSections) {
+    LLVM_DEBUG(dbgs() << "Process remaining sections:\n");
+    for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
+         SI != SE; ++SI) {
+      section_iterator RelocatedSection = SI->getRelocatedSection();
+
+      // Ignore relocation sections
+      if (RelocatedSection != SE)
+        continue;
+
+      bool IsCode = SI->isText();
+      unsigned SectionID = 0;
+      if (auto SectionIDOrErr = findOrEmitSection(Obj, *SI, IsCode,
+                                                  LocalSections))
+        SectionID = *SectionIDOrErr;
+      else
+        return SectionIDOrErr.takeError();
+
+      LLVM_DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
+    }
+  }
+
   // Give the subclasses a chance to tie-up any loose ends.
   if (auto Err = finalizeLoad(Obj, LocalSections))
     return std::move(Err);


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