[builtins] Properly handle arbitrary addresses in builtin lookup

TryLookupCode can be passed arbitrary addresses, e.g. by tentative
name lookups during disassembly. This CL makes sure that addresses
within non-builtin-code sections of the embedded blob (metadata or
padding) are handled properly.

Bug: v8:6666, v8:8334
Change-Id: I42eca57062e30eabd7bb1b069786aa809706cd2c
Reviewed-on: https://chromium-review.googlesource.com/c/1292060Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56865}

src/instruction-stream.cc

@@ -26,12 +26,17 @@ Code* InstructionStream::TryLookupCode(Isolate* isolate, Address address) {
   if (!PcIsOffHeap(isolate, address)) return nullptr;
 
   EmbeddedData d = EmbeddedData::FromBlob();
+  if (address < d.InstructionStartOfBuiltin(0)) return nullptr;
+
+  // Note: Addresses within the padding section between builtins (i.e. within
+  // start + size <= address < start + padded_size) are interpreted as belonging
+  // to the preceding builtin.
 
   int l = 0, r = Builtins::builtin_count;
   while (l < r) {
     const int mid = (l + r) / 2;
     Address start = d.InstructionStartOfBuiltin(mid);
-    Address end = start + d.InstructionSizeOfBuiltin(mid);
+    Address end = start + d.PaddedInstructionSizeOfBuiltin(mid);
 
     if (address < start) {
       r = mid;

src/snapshot/snapshot.h

@@ -96,7 +96,8 @@ class EmbeddedData final {
 
   // Padded with kCodeAlignment.
   uint32_t PaddedInstructionSizeOfBuiltin(int i) const {
-    return PadAndAlign(InstructionSizeOfBuiltin(i));
+    uint32_t size = InstructionSizeOfBuiltin(i);
+    return (size == 0) ? 0 : PadAndAlign(size);
   }
 
   size_t CreateHash() const;

test/cctest/cctest.status

@@ -453,11 +453,4 @@
   'test-dtoa/*': [SKIP],
 }],  # variant == no_wasm_traps
 
-##############################################################################
-['arch == ia32', {
-  # TODO(v8:8334): Fix code printing.
-  'test-assembler-ia32/AssemblerIa32JumpTables1': [SKIP],
-  'test-assembler-ia32/AssemblerIa32JumpTables2': [SKIP],
-}],  # 'arch == ia32'
-
 ]