[llvm] r336120 - [AArch64][GlobalISel] Any-extend vararg parameters to stack slot size on Darwin.

[Amara Emerson via llvm-commits]

Author: aemerson
Date: Mon Jul  2 09:39:09 2018
New Revision: 336120

URL: http://llvm.org/viewvc/llvm-project?rev=336120&view=rev
Log:
[AArch64][GlobalISel] Any-extend vararg parameters to stack slot size on Darwin.

We currently don't any-extend vararg parameters before storing them to the stack
locations on Darwin. However, SelectionDAG however does this, and so user code
is in the wild which inadvertently relies on this extension. This can manifest
in cases where the value stored is (int)0, but the actual parameter is interpreted
by va_arg as a pointer, and so not extending to 64 bits causes the callee to
load additional undefined bits.

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp
    llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv-ios.ll

Modified: llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp?rev=336120&r1=336119&r2=336120&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp Mon Jul  2 09:39:09 2018
@@ -155,6 +155,9 @@ struct OutgoingArgHandler : public CallL
 
   void assignValueToAddress(unsigned ValVReg, unsigned Addr, uint64_t Size,
                             MachinePointerInfo &MPO, CCValAssign &VA) override {
+    if (VA.getLocInfo() == CCValAssign::LocInfo::AExt)
+      Size = VA.getLocVT().getSizeInBits() / 8;
+
     auto MMO = MIRBuilder.getMF().getMachineMemOperand(
         MPO, MachineMemOperand::MOStore, Size, 0);
     MIRBuilder.buildStore(ValVReg, Addr, *MMO);

Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv-ios.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv-ios.ll?rev=336120&r1=336119&r2=336120&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv-ios.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv-ios.ll Mon Jul  2 09:39:09 2018
@@ -16,9 +16,9 @@ target triple = "aarch64-apple-ios9.0"
 ; CHECK: $w0 = COPY [[ANSWER]]
 ; CHECK: $d0 = COPY [[D_ONE]]
 ; CHECK: $x1 = COPY [[TWELVE]]
-; CHECK: G_STORE [[THREE]](s8), {{%[0-9]+}}(p0) :: (store 1 into stack, align 0)
-; CHECK: G_STORE [[ONE]](s16), {{%[0-9]+}}(p0) :: (store 2 into stack + 8, align 0)
-; CHECK: G_STORE [[FOUR]](s32), {{%[0-9]+}}(p0) :: (store 4 into stack + 16, align 0)
+; CHECK: G_STORE [[THREE]](s8), {{%[0-9]+}}(p0) :: (store 8 into stack, align 0)
+; CHECK: G_STORE [[ONE]](s16), {{%[0-9]+}}(p0) :: (store 8 into stack + 8, align 0)
+; CHECK: G_STORE [[FOUR]](s32), {{%[0-9]+}}(p0) :: (store 8 into stack + 16, align 0)
 ; CHECK: G_STORE [[F_ONE]](s32), {{%[0-9]+}}(p0) :: (store 4 into stack + 24, align 0)
 ; CHECK: G_STORE [[TWO]](s64), {{%[0-9]+}}(p0) :: (store 8 into stack + 32, align 0)
 declare void @varargs(i32, double, i64, ...)