From ddad187ce79305cd81fbe9d046de32e05836e134 Mon Sep 17 00:00:00 2001
From: Keno Fischer <kfischer@college.harvard.edu>
Date: Wed, 21 Oct 2015 20:22:04 +0000
Subject: [PATCH] [RuntimeDyld] Ignore ST_FILE symbols when constructing
 GlobalSymbolTable

Summary: ELF's STT_File symbols may overlap with regular globals in
other files, so we should ignore them here in order to avoid having
bogus entries in the symbol table that confuse us when resolving relocations.

Reviewers: lhames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13888

llvm-svn: 250942
---
 .../ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp    |  3 ++-
 .../ExecutionEngine/RuntimeDyld/X86/ELF_STT_FILE.s | 14 ++++++++++++++
 .../RuntimeDyld/X86/Inputs/ELF_STT_FILE_FILE.s     |  3 +++
 .../RuntimeDyld/X86/Inputs/ELF_STT_FILE_GLOBAL.s   |  2 ++
 4 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/ExecutionEngine/RuntimeDyld/X86/ELF_STT_FILE.s
 create mode 100644 llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_FILE.s
 create mode 100644 llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_GLOBAL.s

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 1c276a8728ad..f24a49e8b292 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -179,7 +179,8 @@ RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
       if (Flags & SymbolRef::SF_Exported)
         RTDyldSymFlags |= JITSymbolFlags::Exported;
 
-      if (Flags & SymbolRef::SF_Absolute) {
+      if (Flags & SymbolRef::SF_Absolute &&
+          SymType != object::SymbolRef::ST_File) {
         auto Addr = I->getAddress();
         Check(Addr.getError());
         uint64_t SectOffset = *Addr;
diff --git a/llvm/test/ExecutionEngine/RuntimeDyld/X86/ELF_STT_FILE.s b/llvm/test/ExecutionEngine/RuntimeDyld/X86/ELF_STT_FILE.s
new file mode 100644
index 000000000000..50cc65079bd0
--- /dev/null
+++ b/llvm/test/ExecutionEngine/RuntimeDyld/X86/ELF_STT_FILE.s
@@ -0,0 +1,14 @@
+# RUN: llvm-mc -triple=x86_64-pc-linux -relocation-model=pic -filetype=obj -o %T/test_ELF_STT_FILE_FILE_x86-64.o %p/Inputs/ELF_STT_FILE_FILE.s
+# RUN: llvm-mc -triple=x86_64-pc-linux -relocation-model=pic -filetype=obj -o %T/test_ELF_STT_FILE_GLOBAL_x86-64.o %p/Inputs/ELF_STT_FILE_GLOBAL.s
+# RUN: llvm-mc -triple=x86_64-pc-linux -relocation-model=pic -filetype=obj -o %T/test_ELF_STT_FILE_x86-64.o %s
+# RUN: llvm-rtdyld -triple=x86_64-pc-linux -verify %T/test_ELF_STT_FILE_GLOBAL_x86-64.o %T/test_ELF_STT_FILE_FILE_x86-64.o %T/test_ELF_STT_FILE_x86-64.o
+
+# Test that RTDyldELF ignores STT_FILE symbols, and in particular does
+# crash if we are relocating against a symbol that happens to have the
+# same name as an STT_FILE symbol.
+
+_main:
+    movq    foo.c@GOTPCREL(%rip), %rax
+    movq    bar.c@GOTPCREL(%rip), %rax
+    movq    $0, %rax
+    retq
diff --git a/llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_FILE.s b/llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_FILE.s
new file mode 100644
index 000000000000..7280c51b5867
--- /dev/null
+++ b/llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_FILE.s
@@ -0,0 +1,3 @@
+.file "foo.c"
+.global bar.c
+bar.c:
diff --git a/llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_GLOBAL.s b/llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_GLOBAL.s
new file mode 100644
index 000000000000..a7e5342746e2
--- /dev/null
+++ b/llvm/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ELF_STT_FILE_GLOBAL.s
@@ -0,0 +1,2 @@
+.global foo.c
+foo.c: