[tbb-commits] [tor-browser/tor-browser-45.1.1esr-6.0-1] Bug 1233963 - Work around recent GNU gold behavior with segments starting before the first section they contain

[gk at torproject.org]

commit 1ad955bf2c0a772599f46d2247f06d89508b6d76
Author: Mike Hommey <mh+mozilla at glandium.org>
Date:   Tue Jan 19 14:31:04 2016 +0900

    Bug 1233963 - Work around recent GNU gold behavior with segments starting before the first section they contain
---
 build/unix/elfhack/elf.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/build/unix/elfhack/elf.cpp b/build/unix/elfhack/elf.cpp
index 666b535..743afde 100644
--- a/build/unix/elfhack/elf.cpp
+++ b/build/unix/elfhack/elf.cpp
@@ -258,7 +258,10 @@ Elf::Elf(std::ifstream &file)
                 segment->addSection(sections[j]);
         // Make sure that our view of segments corresponds to the original
         // ELF file.
-        assert(segment->getFileSize() == phdr.p_filesz);
+        // GNU gold likes to start some segments before the first section
+        // they contain. https://sourceware.org/bugzilla/show_bug.cgi?id=19392
+        unsigned int gold_adjustment = segment->getAddr() - phdr.p_vaddr;
+        assert(segment->getFileSize() == phdr.p_filesz - gold_adjustment);
         // gold makes TLS segments end on an aligned virtual address, even
         // when the underlying section ends before that, while bfd ld
         // doesn't. It's fine if we don't keep that alignment.
@@ -267,7 +270,7 @@ Elf::Elf(std::ifstream &file)
             unsigned int align = segment->getAlign();
             memsize = (memsize + align - 1) & ~(align - 1);
         }
-        assert(memsize == phdr.p_memsz);
+        assert(memsize == phdr.p_memsz - gold_adjustment);
         segments.push_back(segment);
     }