From e2684662ee16a6b6b26353c2c8a13dcec894b2cd Mon Sep 17 00:00:00 2001
From: George Rimar <grimar@accesssoftek.com>
Date: Tue, 21 Aug 2018 08:13:06 +0000
Subject: [PATCH] [LLD][ELF] - Check the architecture of lazy objects earlier.

Our code in LazyObjFile::parse() has an ELFT switch and
adds a lazy object by its ELFT kind.
Though it might be possible to add a file using a different
architecture and make LLD to silently accept it (if the file
is empty or contains only week symbols). That itself, not a
huge issue perhaps (because the error would be reported later
if the file is fetched), but still does not look clean and correct.

It is possible to report an error earlier and clean up the
code. That is what the patch does.

Ideally, we might want to reuse isCompatible from SymbolTable.cpp,
but it is static and accepts a file as an argument, what is not
convenient. Since such a situation should be rare, I think it
should be OK to go with the way chosen in this patch.

Differential revision: https://reviews.llvm.org/D50899

llvm-svn: 340257
---
 lld/ELF/InputFiles.cpp            | 18 ++----------------
 lld/ELF/InputFiles.h              |  2 --
 lld/test/ELF/lazy-arch-conflict.s |  7 +++++++
 3 files changed, 9 insertions(+), 18 deletions(-)
 create mode 100644 lld/test/ELF/lazy-arch-conflict.s

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 70189af6d601..0fc99c5b2d72 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -1261,25 +1261,11 @@ template <class ELFT> void LazyObjFile::parse() {
     return;
   }
 
-  switch (getELFKind(this->MB)) {
-  case ELF32LEKind:
-    addElfSymbols<ELF32LE>();
-    return;
-  case ELF32BEKind:
-    addElfSymbols<ELF32BE>();
-    return;
-  case ELF64LEKind:
-    addElfSymbols<ELF64LE>();
+  if (getELFKind(this->MB) != Config->EKind) {
+    error("incompatible file: " + this->MB.getBufferIdentifier());
     return;
-  case ELF64BEKind:
-    addElfSymbols<ELF64BE>();
-    return;
-  default:
-    llvm_unreachable("getELFKind");
   }
-}
 
-template <class ELFT> void LazyObjFile::addElfSymbols() {
   ELFFile<ELFT> Obj = check(ELFFile<ELFT>::create(MB.getBuffer()));
   ArrayRef<typename ELFT::Shdr> Sections = CHECK(Obj.sections(), this);
 
diff --git a/lld/ELF/InputFiles.h b/lld/ELF/InputFiles.h
index 0db3203b0ba2..e31ecbfd4b78 100644
--- a/lld/ELF/InputFiles.h
+++ b/lld/ELF/InputFiles.h
@@ -272,8 +272,6 @@ public:
   bool AddedToLink = false;
 
 private:
-  template <class ELFT> void addElfSymbols();
-
   uint64_t OffsetInArchive;
 };
 
diff --git a/lld/test/ELF/lazy-arch-conflict.s b/lld/test/ELF/lazy-arch-conflict.s
new file mode 100644
index 000000000000..09f2dad866f8
--- /dev/null
+++ b/lld/test/ELF/lazy-arch-conflict.s
@@ -0,0 +1,7 @@
+# REQUIRES: x86
+
+# RUN: echo '.globl foo; .weak foo; .quad foo;' | llvm-mc -filetype=obj -triple=x86_64-unknown-linux - -o %t64.o
+# RUN: echo '.globl foo; foo:' | llvm-mc -filetype=obj -triple=i686-pc-linux - -o %t32.o
+# RUN: not ld.lld %t64.o --start-lib %t32.o --end-lib -o /dev/null 2>&1 | Filecheck %s
+
+# CHECK: error: incompatible file: {{.*}}32.o
-- 
2.34.1