[llvm] 0dd8782 - Add a flag to control whether to propagate labels from condition values to results
Jianzhou Zhao via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 11 12:42:18 PST 2020
Author: Jianzhou Zhao
Date: 2020-11-11T20:41:42Z
New Revision: 0dd87825db2e73c2fb538f710217673ac15b7255
URL: https://github.com/llvm/llvm-project/commit/0dd87825db2e73c2fb538f710217673ac15b7255
DIFF: https://github.com/llvm/llvm-project/commit/0dd87825db2e73c2fb538f710217673ac15b7255.diff
LOG: Add a flag to control whether to propagate labels from condition values to results
Before the change, DFSan always does the propagation. W/o
origin tracking, it is harder to understand such flows. After
the change, the flag is off by default.
Reviewed-by: morehouse
Differential Revision: https://reviews.llvm.org/D91234
Added:
llvm/test/Instrumentation/DataFlowSanitizer/select.ll
Modified:
llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 523e7b19ecb1..9879c9961654 100644
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -186,6 +186,13 @@ static cl::opt<bool> ClFast16Labels(
"labels to 16."),
cl::Hidden, cl::init(false));
+// Controls whether the pass tracks the control flow of select instructions.
+static cl::opt<bool> ClTrackSelectControlFlow(
+ "dfsan-track-select-control-flow",
+ cl::desc("Propagate labels from condition values of select instructions "
+ "to results."),
+ cl::Hidden, cl::init(true));
+
static StringRef GetGlobalTypeString(const GlobalValue &G) {
// Types of GlobalVariables are always pointer types.
Type *GType = G.getValueType();
@@ -1541,22 +1548,21 @@ void DFSanVisitor::visitSelectInst(SelectInst &I) {
Value *CondShadow = DFSF.getShadow(I.getCondition());
Value *TrueShadow = DFSF.getShadow(I.getTrueValue());
Value *FalseShadow = DFSF.getShadow(I.getFalseValue());
+ Value *ShadowSel = nullptr;
if (isa<VectorType>(I.getCondition()->getType())) {
- DFSF.setShadow(
- &I,
- DFSF.combineShadows(
- CondShadow, DFSF.combineShadows(TrueShadow, FalseShadow, &I), &I));
+ ShadowSel = DFSF.combineShadows(TrueShadow, FalseShadow, &I);
} else {
- Value *ShadowSel;
if (TrueShadow == FalseShadow) {
ShadowSel = TrueShadow;
} else {
ShadowSel =
SelectInst::Create(I.getCondition(), TrueShadow, FalseShadow, "", &I);
}
- DFSF.setShadow(&I, DFSF.combineShadows(CondShadow, ShadowSel, &I));
}
+ DFSF.setShadow(&I, ClTrackSelectControlFlow
+ ? DFSF.combineShadows(CondShadow, ShadowSel, &I)
+ : ShadowSel);
}
void DFSanVisitor::visitMemSetInst(MemSetInst &I) {
diff --git a/llvm/test/Instrumentation/DataFlowSanitizer/select.ll b/llvm/test/Instrumentation/DataFlowSanitizer/select.ll
new file mode 100644
index 000000000000..275f8282da16
--- /dev/null
+++ b/llvm/test/Instrumentation/DataFlowSanitizer/select.ll
@@ -0,0 +1,76 @@
+; RUN: opt < %s -dfsan -dfsan-track-select-control-flow=1 -S | FileCheck %s --check-prefix=TRACK_CONTROL_FLOW
+; RUN: opt < %s -dfsan -dfsan-track-select-control-flow=0 -S | FileCheck %s --check-prefix=NO_TRACK_CONTROL_FLOW
+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"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i8 @select8(i1 %c, i8 %t, i8 %f) {
+ ; TRACK_CONTROL_FLOW: %1 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 2)
+ ; TRACK_CONTROL_FLOW: %2 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 1)
+ ; TRACK_CONTROL_FLOW: %3 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 0)
+ ; TRACK_CONTROL_FLOW: %4 = select i1 %c, i16 %2, i16 %1
+ ; TRACK_CONTROL_FLOW: %5 = icmp ne i16 %3, %4
+ ; TRACK_CONTROL_FLOW: %7 = call {{.*}} i16 @__dfsan_union(i16 {{.*}} %3, i16 {{.*}} %4)
+ ; TRACK_CONTROL_FLOW: %9 = phi i16 [ %7, {{.*}} ], [ %3, {{.*}} ]
+ ; TRACK_CONTROL_FLOW: %a = select i1 %c, i8 %t, i8 %f
+ ; TRACK_CONTROL_FLOW: store i16 %9, i16* @__dfsan_retval_tls
+ ; TRACK_CONTROL_FLOW: ret i8 %a
+
+ ; NO_TRACK_CONTROL_FLOW: %1 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 2)
+ ; NO_TRACK_CONTROL_FLOW: %2 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 1)
+ ; NO_TRACK_CONTROL_FLOW: %3 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 0)
+ ; NO_TRACK_CONTROL_FLOW: %4 = select i1 %c, i16 %2, i16 %1
+ ; NO_TRACK_CONTROL_FLOW: %a = select i1 %c, i8 %t, i8 %f
+ ; NO_TRACK_CONTROL_FLOW: store i16 %4, i16* @__dfsan_retval_tls
+ ; NO_TRACK_CONTROL_FLOW: ret i8 %a
+
+ %a = select i1 %c, i8 %t, i8 %f
+ ret i8 %a
+}
+
+define i8 @select8e(i1 %c, i8 %tf) {
+ ; TRACK_CONTROL_FLOW: %1 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 1)
+ ; TRACK_CONTROL_FLOW: %2 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 0)
+ ; TRACK_CONTROL_FLOW: %3 = icmp ne i16 %2, %1
+ ; TRACK_CONTROL_FLOW: %5 = call {{.*}} i16 @__dfsan_union(i16 {{.*}} %2, i16 {{.*}} %1)
+ ; TRACK_CONTROL_FLOW: %7 = phi i16 [ %5, {{.*}} ], [ %2, {{.*}} ]
+ ; TRACK_CONTROL_FLOW: %a = select i1 %c, i8 %tf, i8 %tf
+ ; TRACK_CONTROL_FLOW: store i16 %7, i16* @__dfsan_retval_tls
+ ; TRACK_CONTROL_FLOW: ret i8 %a
+
+ ; NO_TRACK_CONTROL_FLOW: %1 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 1)
+ ; NO_TRACK_CONTROL_FLOW: %2 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 0)
+ ; NO_TRACK_CONTROL_FLOW: %a = select i1 %c, i8 %tf, i8 %tf
+ ; NO_TRACK_CONTROL_FLOW: store i16 %1, i16* @__dfsan_retval_tls
+ ; NO_TRACK_CONTROL_FLOW: ret i8 %a
+
+ %a = select i1 %c, i8 %tf, i8 %tf
+ ret i8 %a
+}
+
+define <4 x i8> @select8v(<4 x i1> %c, <4 x i8> %t, <4 x i8> %f) {
+ ; TRACK_CONTROL_FLOW: %1 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 2)
+ ; TRACK_CONTROL_FLOW: %2 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 1)
+ ; TRACK_CONTROL_FLOW: %3 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 0)
+ ; TRACK_CONTROL_FLOW: %4 = icmp ne i16 %2, %1
+ ; TRACK_CONTROL_FLOW: %6 = call {{.*}} i16 @__dfsan_union(i16 {{.*}} %2, i16 zeroext %1)
+ ; TRACK_CONTROL_FLOW: %8 = phi i16 [ %6, {{.*}} ], [ %2, {{.*}} ]
+ ; TRACK_CONTROL_FLOW: %9 = icmp ne i16 %3, %8
+ ; TRACK_CONTROL_FLOW: %11 = call {{.*}} i16 @__dfsan_union(i16 {{.*}} %3, i16 zeroext %8)
+ ; TRACK_CONTROL_FLOW: %13 = phi i16 [ %11, {{.*}} ], [ %3, {{.*}} ]
+ ; TRACK_CONTROL_FLOW: %a = select <4 x i1> %c, <4 x i8> %t, <4 x i8> %f
+ ; TRACK_CONTROL_FLOW: store i16 %13, i16* @__dfsan_retval_tls
+ ; TRACK_CONTROL_FLOW: ret <4 x i8> %a
+
+ ; NO_TRACK_CONTROL_FLOW: %1 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 2)
+ ; NO_TRACK_CONTROL_FLOW: %2 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 1)
+ ; NO_TRACK_CONTROL_FLOW: %3 = load i16, i16* getelementptr inbounds ([64 x i16], [64 x i16]* @__dfsan_arg_tls, i64 0, i64 0)
+ ; NO_TRACK_CONTROL_FLOW: %4 = icmp ne i16 %2, %1
+ ; NO_TRACK_CONTROL_FLOW: %6 = call {{.*}} i16 @__dfsan_union(i16 {{.*}} %2, i16 {{.*}} %1)
+ ; NO_TRACK_CONTROL_FLOW: %8 = phi i16 [ %6, {{.*}} ], [ %2, {{.*}} ]
+ ; NO_TRACK_CONTROL_FLOW: %a = select <4 x i1> %c, <4 x i8> %t, <4 x i8> %f
+ ; NO_TRACK_CONTROL_FLOW: store i16 %8, i16* @__dfsan_retval_tls
+ ; NO_TRACK_CONTROL_FLOW: ret <4 x i8> %a
+
+ %a = select <4 x i1> %c, <4 x i8> %t, <4 x i8> %f
+ ret <4 x i8> %a
+}
\ No newline at end of file
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