[dfsan] Add explicit zero extensions for shadow parameters in function wrappers.

In the case where dfsan provides a custom wrapper for a function,
shadow parameters are added for each parameter of the function.
These parameters are i16s. For targets which do not consider this
a legal type, the lack of sign extension information would cause
LLVM to generate anyexts around their usage with phi variables
and calling convention logic.

Address this by introducing zero exts for each shadow parameter.

Reviewers: pcc, slthakur

Differential Revision: https://reviews.llvm.org/D33349

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311087 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index a33490f6e4acf5141935d120cf13737cc19d42f9..ddc975cbed1a71db1224336b0b6a09e75f3046ad 100644 (file)
--- a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -1470,6 +1470,7 @@ void DFSanVisitor::visitCallSite(CallSite CS) {
         }
 
         i = CS.arg_begin();
+        const unsigned ShadowArgStart = Args.size();
         for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
           Args.push_back(DFSF.getShadow(*i));
 
@@ -1505,6 +1506,15 @@ void DFSanVisitor::visitCallSite(CallSite CS) {
         CustomCI->setCallingConv(CI->getCallingConv());
         CustomCI->setAttributes(CI->getAttributes());
 
+        // Update the parameter attributes of the custom call instruction to
+        // zero extend the shadow parameters. This is required for targets
+        // which consider ShadowTy an illegal type.
+        for (unsigned n = 0; n < FT->getNumParams(); n++) {
+          const unsigned ArgNo = ShadowArgStart + n;
+          if (CustomCI->getArgOperand(ArgNo)->getType() == DFSF.DFS.ShadowTy)
+            CustomCI->addParamAttr(ArgNo, Attribute::ZExt);
+        }
+
         if (!FT->getReturnType()->isVoidTy()) {
           LoadInst *LabelLoad = IRB.CreateLoad(DFSF.LabelReturnAlloca);
           DFSF.setShadow(CustomCI, LabelLoad);

diff --git a/test/Instrumentation/DataFlowSanitizer/Inputs/shadow-args-abilist.txt b/test/Instrumentation/DataFlowSanitizer/Inputs/shadow-args-abilist.txt
new file mode 100644 (file)
index 0000000..723cbc9
--- /dev/null
+++ b/test/Instrumentation/DataFlowSanitizer/Inputs/shadow-args-abilist.txt
@@ -0,0 +1,8 @@
+fun:dfsan_get_label=uninstrumented
+fun:dfsan_get_label=custom
+
+fun:k2=uninstrumented
+fun:k2=custom
+
+fun:k4=uninstrumented
+fun:k4=custom

diff --git a/test/Instrumentation/DataFlowSanitizer/abilist.ll b/test/Instrumentation/DataFlowSanitizer/abilist.ll
index 8b30875a03fa8c15851ead38fa594e89283ea824..e33237ffe19dcebfd0d44e8af4fd732d3a69bd7a 100644 (file)
--- a/test/Instrumentation/DataFlowSanitizer/abilist.ll
+++ b/test/Instrumentation/DataFlowSanitizer/abilist.ll
@@ -47,13 +47,13 @@ define void @f(i32 %x) {
   ; CHECK: %[[LABELVA1:.*]] = alloca [2 x i16]
   ; CHECK: %[[LABELRETURN:.*]] = alloca i16
 
-  ; CHECK: call void @__dfsw_custom1(i32 1, i32 2, i16 0, i16 0)
+  ; CHECK: call void @__dfsw_custom1(i32 1, i32 2, i16 zeroext 0, i16 zeroext 0)
   call void @custom1(i32 1, i32 2)
 
-  ; CHECK: call i32 @__dfsw_custom2(i32 1, i32 2, i16 0, i16 0, i16* %[[LABELRETURN]])
+  ; CHECK: call i32 @__dfsw_custom2(i32 1, i32 2, i16 zeroext 0, i16 zeroext 0, i16* %[[LABELRETURN]])
   call i32 @custom2(i32 1, i32 2)
 
-  ; CHECK: call void @__dfsw_customcb({{.*}} @"dfst0$customcb", i8* bitcast ({{.*}} @"dfs$cb" to i8*), i16 0)
+  ; CHECK: call void @__dfsw_customcb({{.*}} @"dfst0$customcb", i8* bitcast ({{.*}} @"dfs$cb" to i8*), i16 zeroext 0)
   call void @customcb(i32 (i32)* @cb)
 
   ; CHECK: %[[LABELVA1_0:.*]] = getelementptr inbounds [2 x i16], [2 x i16]* %[[LABELVA1]], i32 0, i32 0
@@ -61,12 +61,12 @@ define void @f(i32 %x) {
   ; CHECK: %[[LABELVA1_1:.*]] = getelementptr inbounds [2 x i16], [2 x i16]* %[[LABELVA1]], i32 0, i32 1
   ; CHECK: store i16 %{{.*}}, i16* %[[LABELVA1_1]]
   ; CHECK: %[[LABELVA1_0A:.*]] = getelementptr inbounds [2 x i16], [2 x i16]* %[[LABELVA1]], i32 0, i32 0
-  ; CHECK: call void (i32, i16, i16*, ...) @__dfsw_custom3(i32 1, i16 0, i16* %[[LABELVA1_0A]], i32 2, i32 %{{.*}})
+  ; CHECK: call void (i32, i16, i16*, ...) @__dfsw_custom3(i32 1, i16 zeroext 0, i16* %[[LABELVA1_0A]], i32 2, i32 %{{.*}})
   call void (i32, ...) @custom3(i32 1, i32 2, i32 %x)
 
   ; CHECK: %[[LABELVA2_0:.*]] = getelementptr inbounds [2 x i16], [2 x i16]* %[[LABELVA2]], i32 0, i32 0
   ; CHECK: %[[LABELVA2_0A:.*]] = getelementptr inbounds [2 x i16], [2 x i16]* %[[LABELVA2]], i32 0, i32 0
-  ; CHECK: call i32 (i32, i16, i16*, i16*, ...) @__dfsw_custom4(i32 1, i16 0, i16* %[[LABELVA2_0A]], i16* %[[LABELRETURN]], i32 2, i32 3)
+  ; CHECK: call i32 (i32, i16, i16*, i16*, ...) @__dfsw_custom4(i32 1, i16 zeroext 0, i16* %[[LABELVA2_0A]], i16* %[[LABELRETURN]], i32 2, i32 3)
   call i32 (i32, ...) @custom4(i32 1, i32 2, i32 3)
 
   ret void

diff --git a/test/Instrumentation/DataFlowSanitizer/shadow-args-zext.ll b/test/Instrumentation/DataFlowSanitizer/shadow-args-zext.ll
new file mode 100644 (file)
index 0000000..0ffbf19
--- /dev/null
+++ b/test/Instrumentation/DataFlowSanitizer/shadow-args-zext.ll
@@ -0,0 +1,54 @@
+; RUN: opt -mtriple=x86_64-unknown-linux-gnu < %s -dfsan -S --dfsan-abilist=%S/Inputs/shadow-args-abilist.txt  | FileCheck %s
+
+; REQUIRES: x86-registered-target
+
+; Test that the custom abi marks shadow parameters as zero extended.
+
+define i32 @m() {
+entry:
+  %call = call zeroext i16 @dfsan_get_label(i64 signext 56)
+  %conv = zext i16 %call to i32
+  ret i32 %conv
+}
+
+; CHECK-LABEL: @"dfs$m"
+; CHECK: %{{.*}} = call zeroext i16 @__dfsw_dfsan_get_label(i64 signext 56, i16 zeroext 0, i16* %{{.*}})
+
+define i32 @k() {
+entry:
+  %call = call zeroext i16 @k2(i64 signext 56, i64 signext 67)
+  %conv = zext i16 %call to i32
+  ret i32 %conv
+}
+
+; CHECK-LABEL: @"dfs$k"
+; CHECK: %{{.*}} = call zeroext i16 @__dfsw_k2(i64 signext 56, i64 signext 67, i16 zeroext {{.*}}, i16 zeroext {{.*}}, i16* %{{.*}})
+
+define i32 @k3() {
+entry:
+  %call = call zeroext i16 @k4(i64 signext 56, i64 signext 67, i64 signext 78, i64 signext 89)
+  %conv = zext i16 %call to i32
+  ret i32 %conv
+}
+
+; CHECK-LABEL: @"dfs$k3"
+; CHECK: %{{.*}} = call zeroext i16 @__dfsw_k4(i64 signext 56, i64 signext 67, i64 signext 78, i64 signext 89, i16 zeroext {{.*}}, i16 zeroext {{.*}}, i16 zeroext {{.*}}, i16 zeroext {{.*}}, i16* %{{.*}})
+
+declare zeroext i16 @dfsan_get_label(i64 signext)
+
+; CHECK-LABEL: @"dfsw$dfsan_get_label"
+; CHECK: %{{.*}} = call i16 @__dfsw_dfsan_get_label(i64 %0, i16 zeroext %1, i16* %{{.*}})
+
+declare zeroext i16 @k2(i64 signext, i64 signext)
+; CHECK-LABEL: @"dfsw$k2"
+; CHECK: %{{.*}} = call i16 @__dfsw_k2(i64 %{{.*}}, i64 %{{.*}}, i16 zeroext %{{.*}}, i16 zeroext %{{.*}}, i16* %{{.*}})
+
+declare zeroext i16 @k4(i64 signext, i64 signext, i64 signext, i64 signext)
+
+; CHECK-LABEL: @"dfsw$k4"
+; CHECK: %{{.*}} = call i16 @__dfsw_k4(i64 %{{.*}}, i64 %{{.*}}, i64  %{{.*}}, i64 %{{.*}}, i16 zeroext %{{.*}}, i16 zeroext %{{.*}}, i16 zeroext %{{.*}}, i16 zeroext %{{.*}}, i16* %{{.*}})
+
+
+; CHECK: declare zeroext i16 @__dfsw_dfsan_get_label(i64 signext, i16, i16*)
+; CHECK: declare zeroext i16 @__dfsw_k2(i64 signext, i64 signext, i16, i16, i16*)
+; CHECK: declare zeroext i16 @__dfsw_k4(i64 signext, i64 signext, i64 signext, i64 signext, i16, i16, i16, i16, i16*)