commit 267f2bf9c3f384bb007c686d165b32959143a247
author John Porto <jpp@chromium.org> Thu Mar 24 06:11:29 2016 -0700
committer John Porto <jpp@chromium.org> Thu Mar 24 06:11:29 2016 -0700
tree e3b54c70089526cc9b5fcae08d36b4bfa0091f5b
parent abe7dd5ff616fcca53099d09b8e747a40879666a

Subzero. Fixes valgrind errors.

Valgrind used to report errors about uninitialized variable access in
Subzero, when it was built with -O2. The problem was traced to

size_t Alignment = Var->getAlignment;
Alignment = std::max(MinAlignment, Var->getAlignment())

Apparently, the compiler will not correctly zero-extend
Var->getAlignment(), and thus Alignment's upper 32-bits would be
garbage.

BUG=
R=kschimpf@google.com, stichnot@chromium.org

Review URL: https://codereview.chromium.org/1825363003 .

src/IceELFObjectWriter.cpp

diff --git a/src/IceELFObjectWriter.cpp b/src/IceELFObjectWriter.cpp
index 26e76f0..98b774b 100644
--- a/src/IceELFObjectWriter.cpp
+++ b/src/IceELFObjectWriter.cpp
@@ -388,9 +388,8 @@
     // entry will be created separately.
     if (!Var->hasInitializer())
       continue;
-    Elf64_Xword Align = Var->getAlignment();
     constexpr Elf64_Xword MinAlign = 1;
-    Align = std::max(Align, MinAlign);
+    const auto Align = std::max<Elf64_Xword>(MinAlign, Var->getAlignment());
     Section->padToAlignment(Str, Align);
     SizeT SymbolSize = Var->getNumBytes();
     bool IsExternal = Var->isExternal() || Ctx.getFlags().getDisableInternal();