[msan] Handle param-tls overflow.

ParamTLS (shadow for function arguments) is of limited size. This change
makes all arguments that do not fit unpoisoned, and avoids writing
past the end of a TLS buffer.

llvm-svn: 220351

1 files changed, 74 insertions, 0 deletions

diff --git a/compiler-rt/test/msan/param_tls_limit.cc b/compiler-rt/test/msan/param_tls_limit.cc
new file mode 100644
index 00000000000..869afc93577
--- /dev/null
+++ b/compiler-rt/test/msan/param_tls_limit.cc
@@ -0,0 +1,74 @@
+// ParamTLS has limited size. Everything that does not fit is considered fully
+// initialized.
+
+// RUN: %clangxx_msan -m64 -O0 %s -o %t && %run %t
+// RUN: %clangxx_msan -fsanitize-memory-track-origins -m64 -O0 %s -o %t && %run %t
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -m64 -O0 %s -o %t && %run %t
+
+#include <sanitizer/msan_interface.h>
+#include <assert.h>
+
+// This test assumes that ParamTLS size is 800 bytes.
+
+// This test passes poisoned values through function argument list.
+// In case of overflow, argument is unpoisoned.
+#define OVERFLOW(x) assert(__msan_test_shadow(&x, sizeof(x)) == -1)
+// In case of no overflow, it is still poisoned.
+#define NO_OVERFLOW(x) assert(__msan_test_shadow(&x, sizeof(x)) == 0)
+
+template<int N>
+struct S {
+  char x[N];
+};
+
+void f100(S<100> s) {
+  NO_OVERFLOW(s);
+}
+
+void f800(S<800> s) {
+  NO_OVERFLOW(s);
+}
+
+void f801(S<801> s) {
+  OVERFLOW(s);
+}
+
+void f1000(S<1000> s) {
+  OVERFLOW(s);
+}
+
+void f_many(int a, double b, S<800> s, int c, double d) {
+  NO_OVERFLOW(a);
+  NO_OVERFLOW(b);
+  OVERFLOW(s);
+  OVERFLOW(c);
+  OVERFLOW(d);
+}
+
+// -8 bytes for "int a", aligned by 8
+// -2 to make "int c" a partial fit
+void f_many2(int a, S<800 - 8 - 2> s, int c, double d) {
+  NO_OVERFLOW(a);
+  NO_OVERFLOW(s);
+  OVERFLOW(c);
+  OVERFLOW(d);
+}
+
+int main(void) {
+  S<100> s100;
+  S<800> s800;
+  S<801> s801;
+  S<1000> s1000;
+  f100(s100);
+  f800(s800);
+  f801(s801);
+  f1000(s1000);
+
+  int i;
+  double d;
+  f_many(i, d, s800, i, d);
+
+  S<800 - 8 - 2> s788;
+  f_many2(i, s788, i, d);
+  return 0;
+}