[compiler-rt][UBSan] Sanitization for alignment assumptions.

Summary:
This is the compiler-rt part.
The clang part is D54589.

This is a second commit, the original one was r351106,
which was mass-reverted in r351159 because 2 compiler-rt tests were failing.

Now, i have fundamentally changed the testing approach:
i malloc a few bytes, intentionally mis-align the pointer
(increment it by one), and check that. Also, i have decreased
the expected alignment. This hopefully should be enough to pacify
all the bots. If not, i guess i might just drop the two 'bad' tests.

Reviewers: filcab, vsk, #sanitizers, vitalybuka, rsmith, morehouse

Reviewed By: morehouse

Subscribers: rjmccall, krytarowski, rsmith, kcc, srhines, kubamracek, dberris, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54590

llvm-svn: 351178

1 files changed, 29 insertions, 0 deletions

diff --git a/compiler-rt/test/ubsan/TestCases/Pointer/alignment-assumption-attribute-alloc_align-on-function.cpp b/compiler-rt/test/ubsan/TestCases/Pointer/alignment-assumption-attribute-alloc_align-on-function.cpp
new file mode 100644
index 00000000000..db22e3a8fcf
--- /dev/null
+++ b/compiler-rt/test/ubsan/TestCases/Pointer/alignment-assumption-attribute-alloc_align-on-function.cpp
@@ -0,0 +1,29 @@
+// RUN: %clang   -x c   -fsanitize=alignment -O0 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+// RUN: %clang   -x c   -fsanitize=alignment -O1 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+// RUN: %clang   -x c   -fsanitize=alignment -O2 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+// RUN: %clang   -x c   -fsanitize=alignment -O3 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+
+// RUN: %clang   -x c++ -fsanitize=alignment -O0 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+// RUN: %clang   -x c++ -fsanitize=alignment -O1 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+// RUN: %clang   -x c++ -fsanitize=alignment -O2 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+// RUN: %clang   -x c++ -fsanitize=alignment -O3 %s -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not=" assumption " --implicit-check-not="note:" --implicit-check-not="error:"
+
+#include <stdlib.h>
+
+char *__attribute__((alloc_align(2)))
+passthrough(char *x, unsigned long alignment) {
+  return x;
+}
+
+int main(int argc, char* argv[]) {
+  char *ptr = (char *)malloc(2);
+
+  passthrough(ptr + 1, 0x8000);
+  // CHECK: {{.*}}alignment-assumption-{{.*}}.cpp:[[@LINE-1]]:3: runtime error: assumption of 32768 byte alignment for pointer of type 'char *' failed
+  // CHECK: {{.*}}alignment-assumption-{{.*}}.cpp:[[@LINE-10]]:22: note: alignment assumption was specified here
+  // CHECK: 0x{{.*}}: note: address is {{.*}} aligned, misalignment offset is {{.*}} byte
+
+  free(ptr);
+
+  return 0;
+}