Add a command line option "-arm-strict-align" to disallow unaligned memory
accesses for ARM targets that would otherwise allow it. Radar 8465431.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114941 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMSubtarget.cpp b/lib/Target/ARM/ARMSubtarget.cpp
index 8a4052b..6ecb512 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -27,6 +27,10 @@
UseMOVT("arm-use-movt",
cl::init(true), cl::Hidden);
+static cl::opt<bool>
+StrictAlign("arm-strict-align", cl::Hidden,
+ cl::desc("Disallow all unaligned memory accesses"));
+
ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &FS,
bool isT)
: ARMArchVersion(V4)
@@ -47,6 +51,7 @@
, HasDataBarrier(false)
, Pref32BitThumb(false)
, FPOnlySP(false)
+ , AllowsUnalignedMem(false)
, stackAlignment(4)
, CPUString("generic")
, TargetType(isELF) // Default to ELF unless otherwise specified.
@@ -122,6 +127,11 @@
if (!isThumb() || hasThumb2())
PostRAScheduler = true;
+
+ // v6+ may or may not support unaligned mem access depending on the system
+ // configuration.
+ if (!StrictAlign && hasV6Ops() && isTargetDarwin())
+ AllowsUnalignedMem = true;
}
/// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.