[RuntimeDyld][COFF] Skip non-loaded sections when calculating ImageBase.

Non-loaded sections (whose unused load-address defaults to zero) should not
be taken into account when calculating ImageBase, or ImageBase will be
incorrectly set to 0.

Patch by Andrew Scheidecker. Thanks Andrew!

https://reviews.llvm.org/D51343

+        // The Sections list may contain sections that weren't loaded for
+        // whatever reason: they may be debug sections, and ProcessAllSections
+        // is false, or they may be sections that contain 0 bytes. If the
+        // section isn't loaded, the load address will be 0, and it should not
+        // be included in the ImageBase calculation.

llvm-svn: 344995

1 files changed, 7 insertions, 1 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFX86_64.h b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFX86_64.h
index 2d6e5c4aea6..39bdc4b6921 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFX86_64.h
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFX86_64.h
@@ -37,7 +37,13 @@ private:
     if (!ImageBase) {
       ImageBase = std::numeric_limits<uint64_t>::max();
       for (const SectionEntry &Section : Sections)
-        ImageBase = std::min(ImageBase, Section.getLoadAddress());
+        // The Sections list may contain sections that weren't loaded for
+        // whatever reason: they may be debug sections, and ProcessAllSections
+        // is false, or they may be sections that contain 0 bytes. If the
+        // section isn't loaded, the load address will be 0, and it should not
+        // be included in the ImageBase calculation.
+        if (Section.getLoadAddress() != 0)
+          ImageBase = std::min(ImageBase, Section.getLoadAddress());
     }
     return ImageBase;
   }