AArch64: Safely handle the incoming sret call argument.

This adds a safe interface to the machine independent InputArg struct
for accessing the index of the original (IR-level) argument. When a
non-native return type is lowered, we generate the hidden
machine-level sret argument on-the-fly. Before this fix, we were
representing this argument as OrigArgIndex == 0, which is an outright
lie. In particular this crashed in the AArch64 backend where we
actually try to access the type of the original argument.

Now we use a sentinel value for machine arguments that have no
original argument index. AArch64, ARM, Mips, and PPC now check for this
case before accessing the original argument.

Fixes <rdar://19792160> Null pointer assertion in AArch64TargetLowering

llvm-svn: 229413

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/R600/R600ISelLowering.cpp b/llvm/lib/Target/R600/R600ISelLowering.cpp
index 70cc876cd93..38e17f13755 100644
--- a/llvm/lib/Target/R600/R600ISelLowering.cpp
+++ b/llvm/lib/Target/R600/R600ISelLowering.cpp
@@ -1693,7 +1693,7 @@ SDValue R600TargetLowering::LowerFormalArguments(
     // XXX - I think PartOffset should give you this, but it seems to give the
     // size of the register which isn't useful.
 
-    unsigned ValBase = ArgLocs[In.OrigArgIndex].getLocMemOffset();
+    unsigned ValBase = ArgLocs[In.getOrigArgIndex()].getLocMemOffset();
     unsigned PartOffset = VA.getLocMemOffset();
     unsigned Offset = 36 + VA.getLocMemOffset();