From a77d9f726a7e3c51f04d1d74d091ae1a87d63544 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Thu, 15 Aug 2013 18:51:12 +0000
Subject: DataFlowSanitizer: Add a debugging feature to help us track nonzero
 labels.

Summary:
When the -dfsan-debug-nonzero-labels parameter is supplied, the code
is instrumented such that when a call parameter, return value or load
produces a nonzero label, the function __dfsan_nonzero_label is called.
The idea is that a debugger breakpoint can be set on this function
in a nominally label-free program to help identify any bugs in the
instrumentation pass causing labels to be introduced.

Reviewers: eugenis

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1405

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188472 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../DataFlowSanitizer/debug-nonzero-labels.ll      | 23 ++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll

(limited to 'test/Instrumentation')

diff --git a/test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll b/test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll
new file mode 100644
index 0000000..4329fd1
--- /dev/null
+++ b/test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll
@@ -0,0 +1,23 @@
+; RUN: opt < %s -dfsan -dfsan-args-abi -dfsan-debug-nonzero-labels -S | FileCheck %s
+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"
+
+declare i32 @g()
+
+; CHECK: define { i32, i16 } @f(i32, i16)
+define i32 @f(i32) {
+  ; CHECK: [[LOCALLABELALLOCA:%.*]] = alloca i16
+  ; CHECK: [[ARGCMP:%.*]] = icmp ne i16 %1, 0
+  ; CHECK: br i1 [[ARGCMP]]
+  %i = alloca i32
+  store i32 %0, i32* %i
+  ; CHECK: [[CALL:%.*]] = call { i32, i16 } @g()
+  ; CHECK: [[CALLLABEL:%.*]] = extractvalue { i32, i16 } [[CALL]], 1
+  ; CHECK: [[CALLCMP:%.*]] = icmp ne i16 [[CALLLABEL]], 0
+  ; CHECK: br i1 [[CALLCMP]]
+  %call = call i32 @g()
+  ; CHECK: [[LOCALLABEL:%.*]] = load i16* [[LOCALLABELALLOCA]]
+  ; CHECK: [[LOCALCMP:%.*]] = icmp ne i16 [[LOCALLABEL]], 0
+  ; CHECK: br i1 [[LOCALCMP]]
+  %load = load i32* %i
+  ret i32 %load
+}
-- 
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