[torque] Fix multi-line AssertStatements

R=tebbi@chromium.org

Bug: v8:7793
Change-Id: I691b3682aec3269350ee02c29b48ce1d46a1ffcb
Reviewed-on: https://chromium-review.googlesource.com/1098656Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#53701}

src/builtins/array.tq

@@ -622,9 +622,8 @@ module array {
       let element: Object = Load<E>(context, elements, i) otherwise Bailout;
       let j: Smi = i - 1;
       for (; j >= from; --j) {
-        // TODO(szuend): Introduce line breaks when multi-line asserts are
-        //               fixed in Torque.
-        assert(CanUseSameAccessor<E>(context, receiver, initialReceiverMap, initialReceiverLength));
+        assert(CanUseSameAccessor<E>(
+            context, receiver, initialReceiverMap, initialReceiverLength));
 
         let tmp: Object = Load<E>(context, elements, j) otherwise Bailout;
         let order: Number = CallCompareFn<E>(
@@ -783,9 +782,8 @@ module array {
       // From low_end to idx are elements equal to pivot.
       // From idx to high_start are elements that haven"t been compared yet.
       for (let idx: Smi = low_end + 1; idx < high_start; idx++) {
-        // TODO(szuend): Introduce line breaks when multi-line asserts are
-        //               fixed in Torque.
-        assert(CanUseSameAccessor<E>(context, receiver, initialReceiverMap, initialReceiverLength));
+        assert(CanUseSameAccessor<E>(
+            context, receiver, initialReceiverMap, initialReceiverLength));
 
         let element: Object = Load<E>(context, elements, idx) otherwise Bailout;
         let order: Number = CallCompareFn<E>(

src/torque/implementation-visitor.cc

@@ -679,6 +679,24 @@ const Type* ImplementationVisitor::Visit(DebugStatement* stmt) {
   }
 }
 
+namespace {
+
+std::string FormatAssertSource(const std::string& str) {
+  // Replace all whitespace characters with a space character.
+  std::string str_no_newlines = str;
+  std::replace_if(str_no_newlines.begin(), str_no_newlines.end(),
+                  [](unsigned char c) { return isspace(c); }, ' ');
+
+  // str might include indentation, squash multiple space characters into one.
+  std::string result;
+  std::unique_copy(str_no_newlines.begin(), str_no_newlines.end(),
+                   std::back_inserter(result),
+                   [](char a, char b) { return a == ' ' && b == ' '; });
+  return result;
+}
+
+}  // namespace
+
 const Type* ImplementationVisitor::Visit(AssertStatement* stmt) {
   bool do_check = !stmt->debug_only;
 #if defined(DEBUG)
@@ -717,8 +735,9 @@ const Type* ImplementationVisitor::Visit(AssertStatement* stmt) {
     GenerateLabelBind(false_label);
     GenerateIndent();
     source_out() << "Print(\""
-                 << "assert '" << stmt->source << "' failed at "
-                 << PositionAsString(stmt->pos) << "\");" << std::endl;
+                 << "assert '" << FormatAssertSource(stmt->source)
+                 << "' failed at " << PositionAsString(stmt->pos) << "\");"
+                 << std::endl;
     GenerateIndent();
     source_out() << "Unreachable();" << std::endl;
 

test/torque/test-torque.tq

@@ -213,4 +213,10 @@ module test {
     let x: int32 = 0x40000000;
     let y: int32 = 0x7fffffff;
   }
+
+  macro TestMultilineAssert() {
+    let someVeryLongVariableNameThatWillCauseLineBreaks: Smi = 5;
+    check(someVeryLongVariableNameThatWillCauseLineBreaks > 0
+           && someVeryLongVariableNameThatWillCauseLineBreaks < 10);
+  }
 }