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[builtins] Introduce a symbol for each embedded builtin

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This should improve the debugging experience since backtraces will
list the exact builtin instead of just 'embedded_blob'. An example
gdb backtrace:

 #0  <snip address> in Builtins_RegExpPrototypeExec ()
 #1  <snip address> in Builtins_ArgumentsAdaptorTrampoline ()
 <snip further frames>

Bug: v8:6666, v8:7722
Change-Id: Iafc995779903e7d7a980d66e7dad42938ac7d29e
Reviewed-on: https://chromium-review.googlesource.com/1145183
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54598}
This commit is contained in:
jgruber 2018-07-20 13:46:48 +02:00 committed by Commit Bot
parent 039c18e19a
commit d20883f441
1 changed files with 37 additions and 3 deletions
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40
src/snapshot/mksnapshot.cc
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@ -153,6 +153,9 @@ class SnapshotWriter {
static void WriteEmbeddedFileData(FILE* fp, const i::EmbeddedData* blob,
const char* embedded_variant) {
fprintf(fp, "V8_EMBEDDED_TEXT_HEADER(v8_%s_embedded_blob_)\n",
embedded_variant);
#ifdef V8_OS_MACOSX
// Note: On some platforms (observed on mac64), inserting labels into the
// .byte stream causes the compiler to reorder symbols, invalidating stored
// offsets.
@ -161,16 +164,47 @@ class SnapshotWriter {
// there since the chrome build process on mac verifies the order of symbols
// present in the binary.
// For now, the straight-forward solution seems to be to just emit a pure
// .byte stream.
fprintf(fp, "V8_EMBEDDED_TEXT_HEADER(v8_%s_embedded_blob_)\n",
embedded_variant);
// .byte stream on OSX.
WriteBinaryContentsAsByteDirective(fp, blob->data(), blob->size());
#else
WriteBinaryContentsAsByteDirective(fp, blob->data(),
i::EmbeddedData::RawDataOffset());
WriteBuiltins(fp, blob, embedded_variant);
#endif
fprintf(fp, "extern \"C\" const uint8_t v8_%s_embedded_blob_[];\n",
embedded_variant);
fprintf(fp, "static const uint32_t v8_embedded_blob_size_ = %d;\n\n",
blob->size());
}
static void WriteBuiltins(FILE* fp, const i::EmbeddedData* blob,
const char* embedded_variant) {
const bool is_default_variant =
std::strcmp(embedded_variant, "Default") == 0;
for (int i = 0; i < i::Builtins::builtin_count; i++) {
if (!blob->ContainsBuiltin(i)) continue;
// Labels created here will show up in backtraces. We check in
// Isolate::SetEmbeddedBlob that the blob layout remains unchanged, i.e.
// that labels do not insert bytes into the middle of the blob byte
// stream.
if (is_default_variant) {
// Create nicer symbol names for the default mode.
fprintf(fp, "__asm__(V8_ASM_LABEL(\"Builtins_%s\"));\n",
i::Builtins::name(i));
} else {
fprintf(fp, "__asm__(V8_ASM_LABEL(\"%s_Builtins_%s\"));\n",
embedded_variant, i::Builtins::name(i));
}
WriteBinaryContentsAsByteDirective(
fp,
reinterpret_cast<const uint8_t*>(blob->InstructionStartOfBuiltin(i)),
blob->PaddedInstructionSizeOfBuiltin(i));
}
fprintf(fp, "\n");
}
static void WriteBinaryContentsAsByteDirective(FILE* fp, const uint8_t* data,
uint32_t size) {
static const int kTextWidth = 80;