From 142fdff0d5eb2b39df3254691cd00bf50f10cf36 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Fri, 1 Aug 2014 21:18:18 +0000
Subject: [PATCH] [dfsan] Correctly handle loads and stores of zero size.

llvm-svn: 214561
---
 llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp |  8 ++++++++
 llvm/test/Instrumentation/DataFlowSanitizer/load.ll       | 14 +++++++++++++-
 llvm/test/Instrumentation/DataFlowSanitizer/store.ll      | 13 +++++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 35057cdd..aa68ff5 100644
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -1092,6 +1092,11 @@ Value *DFSanFunction::loadShadow(Value *Addr, uint64_t Size, uint64_t Align,
 
 void DFSanVisitor::visitLoadInst(LoadInst &LI) {
   uint64_t Size = DFSF.DFS.DL->getTypeStoreSize(LI.getType());
+  if (Size == 0) {
+    DFSF.setShadow(&LI, DFSF.DFS.ZeroShadow);
+    return;
+  }
+
   uint64_t Align;
   if (ClPreserveAlignment) {
     Align = LI.getAlignment();
@@ -1166,6 +1171,9 @@ void DFSanFunction::storeShadow(Value *Addr, uint64_t Size, uint64_t Align,
 void DFSanVisitor::visitStoreInst(StoreInst &SI) {
   uint64_t Size =
       DFSF.DFS.DL->getTypeStoreSize(SI.getValueOperand()->getType());
+  if (Size == 0)
+    return;
+
   uint64_t Align;
   if (ClPreserveAlignment) {
     Align = SI.getAlignment();
diff --git a/llvm/test/Instrumentation/DataFlowSanitizer/load.ll b/llvm/test/Instrumentation/DataFlowSanitizer/load.ll
index 6cd5151..8324224 100644
--- a/llvm/test/Instrumentation/DataFlowSanitizer/load.ll
+++ b/llvm/test/Instrumentation/DataFlowSanitizer/load.ll
@@ -2,6 +2,18 @@
 ; RUN: opt < %s -dfsan -dfsan-combine-pointer-labels-on-load=0 -S | FileCheck %s --check-prefix=NO_COMBINE_PTR_LABEL
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 
+define {} @load0({}* %p) {
+  ; COMBINE_PTR_LABEL: @"dfs$load0"
+  ; COMBINE_PTR_LABEL: load
+  ; COMBINE_PTR_LABEL-NOT: load
+
+  ; NO_COMBINE_PTR_LABEL: @"dfs$load0"
+  ; NO_COMBINE_PTR_LABEL: load
+  ; NO_COMBINE_PTR_LABEL-NOT: load
+  %a = load {}* %p
+  ret {} %a
+}
+
 define i8 @load8(i8* %p) {
   ; COMBINE_PTR_LABEL: @"dfs$load8"
   ; COMBINE_PTR_LABEL: load i16*
@@ -152,4 +164,4 @@ define i64 @load64(i64* %p) {
 
   %a = load i64* %p
   ret i64 %a
-}
\ No newline at end of file
+}
diff --git a/llvm/test/Instrumentation/DataFlowSanitizer/store.ll b/llvm/test/Instrumentation/DataFlowSanitizer/store.ll
index 8060537..d14bdb6 100644
--- a/llvm/test/Instrumentation/DataFlowSanitizer/store.ll
+++ b/llvm/test/Instrumentation/DataFlowSanitizer/store.ll
@@ -2,6 +2,19 @@
 ; RUN: opt < %s -dfsan -dfsan-combine-pointer-labels-on-store=0 -S | FileCheck %s --check-prefix=NO_COMBINE_PTR_LABEL
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 
+define void @store0({} %v, {}* %p) {
+  ; COMBINE_PTR_LABEL: @"dfs$store0"
+  ; COMBINE_PTR_LABEL: store
+  ; COMBINE_PTR_LABEL-NOT: store
+
+  ; NO_COMBINE_PTR_LABEL: @"dfs$store0"
+  ; NO_COMBINE_PTR_LABEL: store
+  ; NO_COMBINE_PTR_LABEL-NOT: store
+
+  store {} %v, {}* %p
+  ret void
+}
+
 define void @store8(i8 %v, i8* %p) {
   ; NO_COMBINE_PTR_LABEL: @"dfs$store8"
   ; NO_COMBINE_PTR_LABEL: load i16* {{.*}} @__dfsan_arg_tls
-- 
2.7.4