[llvm] r220101 - [msan] Fix handling of byval arguments with large alignment.

[Evgeniy Stepanov]

Author: eugenis
Date: Fri Oct 17 18:29:44 2014
New Revision: 220101

URL: http://llvm.org/viewvc/llvm-project?rev=220101&view=rev
Log:
[msan] Fix handling of byval arguments with large alignment.

MSan param-tls slots are 8-byte aligned. This change clips
alignment of memcpy into param-tls to 8.

Added:
    llvm/trunk/test/Instrumentation/MemorySanitizer/byval-alignment.ll
Modified:
    llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp

Modified: llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp?rev=220101&r1=220100&r2=220101&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp Fri Oct 17 18:29:44 2014
@@ -2329,7 +2329,8 @@ struct MemorySanitizerVisitor : public I
         assert(A->getType()->isPointerTy() &&
                "ByVal argument is not a pointer!");
         Size = MS.DL->getTypeAllocSize(A->getType()->getPointerElementType());
-        unsigned Alignment = CS.getParamAlignment(i + 1);
+        unsigned ParamAlignment = CS.getParamAlignment(i + 1);
+        unsigned Alignment = std::min(ParamAlignment, kShadowTLSAlignment);
         Store = IRB.CreateMemCpy(ArgShadowBase,
                                  getShadowPtr(A, Type::getInt8Ty(*MS.C), IRB),
                                  Size, Alignment);

Added: llvm/trunk/test/Instrumentation/MemorySanitizer/byval-alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/MemorySanitizer/byval-alignment.ll?rev=220101&view=auto
==============================================================================
--- llvm/trunk/test/Instrumentation/MemorySanitizer/byval-alignment.ll (added)
+++ llvm/trunk/test/Instrumentation/MemorySanitizer/byval-alignment.ll Fri Oct 17 18:29:44 2014
@@ -0,0 +1,20 @@
+; Test that copy alignment for byval arguments is limited by param-tls slot alignment.
+
+; RUN: opt < %s -msan -msan-check-access-address=0 -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.S = type { i64, i64, i64, [8 x i8] }
+
+; CHECK: [[A:%.*]] = bitcast i64* {{.*}} add {{.*}} ptrtoint {{.*}} @__msan_param_tls {{.*}} i64 8)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[A]], i8* {{.*}}, i64 32, i32 8, i1 false)
+
+define void @Caller() sanitize_memory {
+entry:
+  %agg.tmp = alloca %struct.S, align 16
+  call void @Callee(i32 1, %struct.S* byval align 16 %agg.tmp)
+  ret void
+}
+
+declare void @Callee(i32, %struct.S* byval align 16)