Add Travis builds with sanitizers

This triggers 5 independent build / test runs:
 - clang, no sanitizer;
 - clang, UB sanitizer;
 - clang, address sanitizer (disabled for now);
 - clang, thread sanitizer (disabled for now);
 - GCC.

Enabling UBSan led to these changes:
 - Fix a bunch of undefined behavior throughout the code base.
 - Fix some tests that relied on that undefined behavior.
 - Make some of the tests easier to debug by printing their command line.
 - Add ubsan blacklist to work around libstdc++ bug.
 - Example testcase also needs sanitizer because libsupport.a uses it.

1 files changed, 6 insertions, 3 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index db7cc1ae0..c72c7e98a 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -385,7 +385,7 @@ private:
       }
       if (ast[1] == MINUS && ast[2][0] == NUM) {
         double num = -ast[2][1]->getNumber();
-        assert(isInteger32(num));
+        assert(isSInteger32(num));
         return Literal((int32_t)num);
       }
       if (ast[1] == PLUS && ast[2][0] == UNARY_PREFIX && ast[2][1] == MINUS && ast[2][2][0] == NUM) {
@@ -912,9 +912,12 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
     } else if (what == NUM) {
       auto ret = allocator.alloc<Const>();
       double num = ast[1]->getNumber();
-      if (isInteger32(num)) {
+      if (isSInteger32(num)) {
         ret->value.type = WasmType::i32;
-        ret->value.i32 = toInteger32(num);
+        ret->value.i32 = toSInteger32(num);
+      } else if (isUInteger32(num)) {
+        ret->value.type = WasmType::i32;
+        ret->value.i32 = toUInteger32(num);
       } else {
         ret->value.type = WasmType::f64;
         ret->value.f64 = num;