From 9ca96384f34c6dd3c63be5482616e50500fb1f43 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Mon, 7 Mar 2016 14:05:09 +0000
Subject: [PATCH] [DFSan] Remove an overly aggressive assert reported in
 PR26068.

This code has been successfully used to bootstrap libc++ in a no-asserts
mode for a very long time, so the code that follows cannot be completely
incorrect. I've added a test that shows the current behavior for this
kind of code with DFSan. If it is desirable for DFSan to do something
special when processing an invoke of a variadic function, it can be
added, but we shouldn't keep an assert that we've been ignoring due to
release builds anyways.

llvm-svn: 262829
---
 .../Instrumentation/DataFlowSanitizer.cpp          |  4 --
 .../test/Instrumentation/DataFlowSanitizer/call.ll | 43 ++++++++++++++++++++--
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 42f4701..c964a1f 100644
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -1412,10 +1412,6 @@ void DFSanVisitor::visitCallSite(CallSite CS) {
   if (F == DFSF.DFS.DFSanVarargWrapperFn)
     return;
 
-  assert(!(cast<FunctionType>(
-      CS.getCalledValue()->getType()->getPointerElementType())->isVarArg() &&
-           dyn_cast<InvokeInst>(CS.getInstruction())));
-
   IRBuilder<> IRB(CS.getInstruction());
 
   DenseMap<Value *, Function *>::iterator i =
diff --git a/llvm/test/Instrumentation/DataFlowSanitizer/call.ll b/llvm/test/Instrumentation/DataFlowSanitizer/call.ll
index dadb40f..f196d1b 100644
--- a/llvm/test/Instrumentation/DataFlowSanitizer/call.ll
+++ b/llvm/test/Instrumentation/DataFlowSanitizer/call.ll
@@ -2,13 +2,16 @@
 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"
 
-; CHECK: @__dfsan_arg_tls = external thread_local(initialexec) global [64 x i16]
-; CHECK: @__dfsan_retval_tls = external thread_local(initialexec) global i16
+; CHECK-LABEL: @__dfsan_arg_tls
+; CHECK: = external thread_local(initialexec) global [64 x i16]
+
+; CHECK-LABEL: @__dfsan_retval_tls
+; CHECK: = external thread_local(initialexec) global i16
 
 declare i32 @f(i32)
 declare float @llvm.sqrt.f32(float)
 
-; CHECK: @"dfs$call"
+; CHECK-LABEL: @"dfs$call"
 define i32 @call() {
   ; CHECK: store{{.*}}__dfsan_arg_tls
   ; CHECK: call{{.*}}@"dfs$f"
@@ -22,3 +25,37 @@ define i32 @call() {
   ; CHECK: ret i32
   ret i32 %r
 }
+
+declare i32 @__gxx_personality_v0(...)
+
+declare i8* @__cxa_begin_catch(i8*)
+
+declare void @__cxa_end_catch()
+
+declare void @g(...)
+
+; CHECK-LABEL: @"dfs$h"
+; CHECK: personality {{.*}} @"dfs$__gxx_personality_v0" {{.*}} {
+define i32 @h() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+; CHECK: invoke void (...) @"dfs$g"(i32 42)
+  invoke void (...) @g(i32 42)
+          to label %try.cont unwind label %lpad
+
+lpad:
+  %0 = landingpad { i8*, i32 }
+          catch i8* null
+  %1 = extractvalue { i8*, i32 } %0, 0
+
+  ; CHECK: store {{.*}} @__dfsan_arg_tls
+  ; CHECK: call {{.*}} @"dfs$__cxa_begin_catch"
+  ; CHECK: load {{.*}} @__dfsan_retval_tls
+  %2 = tail call i8* @__cxa_begin_catch(i8* %1)
+
+  ; CHECK: call {{.*}} @"dfs$__cxa_end_catch"
+  tail call void @__cxa_end_catch()
+  br label %try.cont
+
+try.cont:
+  ret i32 0
+}
-- 
2.7.4