Enforce asm restrictions on switch more precisely.

Enforce cases have no duplicates.
Enforce cases have a maximum range of 2^31.
Enforce default case comes last.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=test-asm-validator
R=aseemgarg@chromium.org,titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1578963003

Cr-Commit-Position: refs/heads/master@{#33221}

src/typing-asm.cc

@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "src/v8.h"
-
 #include "src/typing-asm.h"
 
+#include <limits>
+
+#include "src/v8.h"
+
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/codegen.h"
@@ -386,9 +388,14 @@ void AsmTyper::VisitSwitchStatement(SwitchStatement* stmt) {
   RECURSE(VisitWithExpectation(stmt->tag(), cache_.kAsmSigned,
                                "switch expression non-integer"));
   ZoneList<CaseClause*>* clauses = stmt->cases();
+  ZoneSet<int32_t> cases(zone());
   for (int i = 0; i < clauses->length(); ++i) {
     CaseClause* clause = clauses->at(i);
-    if (!clause->is_default()) {
+    if (clause->is_default()) {
+      if (i != clauses->length() - 1) {
+        FAIL(clause, "default case out of order");
+      }
+    } else {
       Expression* label = clause->label();
       RECURSE(VisitWithExpectation(label, cache_.kAsmSigned,
                                    "case label non-integer"));
@@ -396,11 +403,22 @@ void AsmTyper::VisitSwitchStatement(SwitchStatement* stmt) {
       Handle<Object> value = label->AsLiteral()->value();
       int32_t value32;
       if (!value->ToInt32(&value32)) FAIL(label, "illegal case label value");
+      if (cases.find(value32) != cases.end()) {
+        FAIL(label, "duplicate case value");
+      }
+      cases.insert(value32);
     }
     // TODO(bradnelson): Detect duplicates.
     ZoneList<Statement*>* stmts = clause->statements();
     RECURSE(VisitStatements(stmts));
   }
+  if (cases.size() > 0) {
+    int64_t min_case = *cases.begin();
+    int64_t max_case = *cases.rbegin();
+    if (max_case - min_case > std::numeric_limits<int32_t>::max()) {
+      FAIL(stmt, "case range too large");
+    }
+  }
 }
 
 

test/cctest/test-asm-validator.cc

@@ -2024,3 +2024,27 @@ TEST(SwitchTest) {
   }
   CHECK_FUNC_TYPES_END
 }
+
+
+TEST(BadSwitchRange) {
+  CHECK_FUNC_ERROR(
+      "function bar() { switch (1) { case -1: case 0x7fffffff: } }\n"
+      "function foo() { bar(); }",
+      "asm: line 39: case range too large\n");
+}
+
+
+TEST(DuplicateSwitchCase) {
+  CHECK_FUNC_ERROR(
+      "function bar() { switch (1) { case 0: case 0: } }\n"
+      "function foo() { bar(); }",
+      "asm: line 39: duplicate case value\n");
+}
+
+
+TEST(BadSwitchOrder) {
+  CHECK_FUNC_ERROR(
+      "function bar() { switch (1) { default: case 0: } }\n"
+      "function foo() { bar(); }",
+      "asm: line 39: default case out of order\n");
+}