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Update for v8 4.6 #37

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Oct 2, 2015
Merged

Update for v8 4.6 #37

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112 changes: 97 additions & 15 deletions src/mdb_v8.c
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Original file line number Diff line number Diff line change
Expand Up @@ -198,6 +198,7 @@ ssize_t V8_OFF_JSOBJECT_PROPERTIES;
ssize_t V8_OFF_MAP_CONSTRUCTOR;
ssize_t V8_OFF_MAP_CONSTRUCTOR_OR_BACKPOINTER;
ssize_t V8_OFF_MAP_INOBJECT_PROPERTIES;
ssize_t V8_OFF_MAP_INOBJECT_PROPERTIES_OR_CTOR_FUN_INDEX;
ssize_t V8_OFF_MAP_INSTANCE_ATTRIBUTES;
ssize_t V8_OFF_MAP_INSTANCE_DESCRIPTORS;
ssize_t V8_OFF_MAP_INSTANCE_SIZE;
Expand All @@ -224,6 +225,9 @@ ssize_t V8_OFF_SLICEDSTRING_PARENT;
ssize_t V8_OFF_SLICEDSTRING_OFFSET;
ssize_t V8_OFF_STRING_LENGTH;
ssize_t V8_OFF_JSTYPEDARRAY_LENGTH;
ssize_t V8_OFF_JSARRAYBUFFER_BACKINGSTORE;
ssize_t V8_OFF_JSARRAYBUFFERVIEW_BUFFER;
ssize_t V8_OFF_JSARRAYBUFFERVIEW_CONTENT_OFFSET;

/* see node_string.h */
#define NODE_OFF_EXTSTR_DATA sizeof (uintptr_t)
Expand Down Expand Up @@ -424,7 +428,17 @@ static v8_offset_t v8_offsets[] = {
"Map", "constructor_or_backpointer",
B_FALSE, V8_CONSTANT_ADDED_SINCE(4, 3)},
{ &V8_OFF_MAP_INOBJECT_PROPERTIES,
"Map", "inobject_properties" },
"Map", "inobject_properties",
B_FALSE, V8_CONSTANT_REMOVED_SINCE(4, 6) },
#ifdef _LP64
{ &V8_OFF_MAP_INOBJECT_PROPERTIES_OR_CTOR_FUN_INDEX,
"Map", "inobject_properties_or_constructor_function_index",
B_FALSE, V8_CONSTANT_FALLBACK(4, 6), 8 },
#else
{ &V8_OFF_MAP_INOBJECT_PROPERTIES_OR_CTOR_FUN_INDEX,
"Map", "inobject_properties_or_constructor_function_index",
B_FALSE, V8_CONSTANT_FALLBACK(4, 6), 4 },
#endif
{ &V8_OFF_MAP_INSTANCE_ATTRIBUTES,
"Map", "instance_attributes" },
{ &V8_OFF_MAP_INSTANCE_DESCRIPTORS,
Expand Down Expand Up @@ -482,6 +496,26 @@ static v8_offset_t v8_offsets[] = {
"JSTypedArray", "length",
B_FALSE, V8_CONSTANT_FALLBACK(4, 5), 27 },
#endif
#ifdef _LP64
{ &V8_OFF_JSARRAYBUFFER_BACKINGSTORE,
"JSArrayBuffer", "backing_store",
B_FALSE, V8_CONSTANT_FALLBACK(4, 6), 23 },
#else
{ &V8_OFF_JSARRAYBUFFER_BACKINGSTORE,
"JSArrayBuffer", "backing_store",
B_FALSE, V8_CONSTANT_FALLBACK(4, 6), 11 },
#endif
{ &V8_OFF_JSARRAYBUFFERVIEW_BUFFER,
"JSArrayBufferView", "buffer" },
#ifdef _LP64
{ &V8_OFF_JSARRAYBUFFERVIEW_CONTENT_OFFSET,
"JSArrayBufferView", "byte_offset",
B_FALSE, V8_CONSTANT_FALLBACK(4, 6), 31 },
#else
{ &V8_OFF_JSARRAYBUFFERVIEW_CONTENT_OFFSET,
"JSArrayBufferView", "byte_offset",
B_FALSE, V8_CONSTANT_FALLBACK(4, 6), 15 },
#endif
};

static int v8_noffsets = sizeof (v8_offsets) / sizeof (v8_offsets[0]);
Expand Down Expand Up @@ -877,6 +911,10 @@ autoconfigure(v8_cfg_t *cfgp)
if (V8_OFF_MAP_CONSTRUCTOR_OR_BACKPOINTER != -1)
V8_OFF_MAP_CONSTRUCTOR = V8_OFF_MAP_CONSTRUCTOR_OR_BACKPOINTER;

if (V8_OFF_MAP_INOBJECT_PROPERTIES_OR_CTOR_FUN_INDEX != -1)
V8_OFF_MAP_INOBJECT_PROPERTIES =
V8_OFF_MAP_INOBJECT_PROPERTIES_OR_CTOR_FUN_INDEX;

return (failed ? -1 : 0);
}

Expand Down Expand Up @@ -5420,6 +5458,8 @@ dcmd_nodebuffer(uintptr_t addr, uint_t flags, int argc,
char *bufp = buf;
size_t len = sizeof (buf);
uintptr_t elts, rawbuf;
uintptr_t arraybuffer_view_buffer;
uintptr_t arraybufferview_content_offset;

/*
* The undocumented "-f" option allows users to override constructor
Expand All @@ -5440,21 +5480,63 @@ dcmd_nodebuffer(uintptr_t addr, uint_t flags, int argc,
}
}

/*
* This works for Buffer instance in node < 4.0 because they use
* elements slots to reference the backing storage. It also works
* with Buffer in node >= 4.0 because they actually are typed arrays
* and typed arrays use elements slots to store the external data.
* We could use the "backing_store" member of the JSArrayBuffer
* associated to a typed array instead, but using elements for
* both "old" Buffer instances and new ones has the benefit of
* being able to reuse more code.
*/
if (read_heap_ptr(&elts, addr, V8_OFF_JSOBJECT_ELEMENTS) != 0)
return (DCMD_ERR);
if (strcmp(buf, "Buffer") == 0 ||
V8_OFF_JSARRAYBUFFER_BACKINGSTORE == -1) {
/*
* This works for Buffer instances in node < 4.0 because they
* use elements slots to reference the backing storage. If
* the constructor name is not "Buffer" but "Uint8Array" and
* V8_OFF_JSARRAYBUFFER_BACKINGSTORE == -1, it means we are in
* the range of node versions >= 4.0 and <= 4.1 that ship with
* V8 4.5.x. For these versions, it also works because Buffer
* instances are actually typed arrays but their backing storage
* an ExternalUint8Arrayelements whose address is stored in the
* first element's slot.
*/
if (read_heap_ptr(&elts, addr, V8_OFF_JSOBJECT_ELEMENTS) != 0)
return (DCMD_ERR);

if (obj_v8internal(elts, 0, &rawbuf) != 0)
return (DCMD_ERR);
if (obj_v8internal(elts, 0, &rawbuf) != 0)
return (DCMD_ERR);
} else {
/*
* The buffer instance's constructor name is Uint8Array, and
* V8_OFF_JSARRAYBUFFER_BACKINGSTORE != -1, which means that
* we're dealing with a node version that ships with V8 4.6 or
* later. For these versions, buffer instances store their data
* as a typed array, but this time instead of having the backing
* store as an ExternalUint8Array referenced from an element
* slot, it can be found at two different locations:
*
* 1. As a FixedTypedArray casted as a FixedTypedArrayBase in an
* element slot.
*
* 2. As the "backing_store" property of the corresponding
* JSArrayBuffer.
*
* The second way to retrieve the backing store seems like
* it will be less likely to change, and is thus the one we're
* using.
*/
if (V8_OFF_JSARRAYBUFFER_BACKINGSTORE == -1 ||
V8_OFF_JSARRAYBUFFERVIEW_BUFFER == -1 ||
V8_OFF_JSARRAYBUFFERVIEW_CONTENT_OFFSET == -1)
return (DCMD_ERR);

if (read_heap_ptr(&arraybuffer_view_buffer, addr,
V8_OFF_JSARRAYBUFFERVIEW_BUFFER) != 0)
return (DCMD_ERR);

if (read_heap_ptr(&rawbuf, arraybuffer_view_buffer,
V8_OFF_JSARRAYBUFFER_BACKINGSTORE) != 0)
return (DCMD_ERR);

if (read_heap_smi(&arraybufferview_content_offset, addr,
V8_OFF_JSARRAYBUFFERVIEW_CONTENT_OFFSET) != 0)
return (DCMD_ERR);

rawbuf += arraybufferview_content_offset;
}

mdb_printf("%p\n", rawbuf);
return (DCMD_OK);
Expand Down
43 changes: 33 additions & 10 deletions test/standalone/tst.postmortem_details.js
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Original file line number Diff line number Diff line change
Expand Up @@ -14,9 +14,17 @@ var os = require('os');
var path = require('path');
var util = require('util');

var NODE_MAJOR = Number(process.versions.node.split('.')[0]);
var NODE_VERSIONS = process.versions.node.split('.');
var NODE_MAJOR = Number(NODE_VERSIONS[0]);
assert.equal(isNaN(NODE_MAJOR), false);

var V8_VERSIONS = process.versions.v8.split('.');
var V8_MAJOR = Number(V8_VERSIONS[0]);
assert.equal(isNaN(V8_MAJOR), false);

var V8_MINOR = Number(V8_VERSIONS[1]);
assert.equal(isNaN(V8_MINOR), false);

/*
* We're going to look specifically for this function and buffer in the core
* file.
Expand Down Expand Up @@ -135,9 +143,17 @@ gcore.on('exit', function (code) {
assert.equal(testlines.length, 1);
assert.equal(testlines[0], '0x' + buffer + ': Hello');
});
verifiers.push(function verifyV8internal(testlines) {
assert.deepEqual(testlines, [ buffer ]);
});
// Buffer instances are implemented as typed arrays in Node
// versions that ship with V8 >= 4.6. Typed arrays in these versions
// of V8 do not *directly* store their underlying buffer as an
// "internal" element, so ::v8internal would not output its address.
// It would instead output the address of a FixedTypedArrayBase
// instance. Thus, skip the test.
if (V8_MAJOR < 4 || V8_MAJOR === 4 && V8_MINOR < 6) {
verifiers.push(function verifyV8internal(testlines) {
assert.deepEqual(testlines, [ buffer ]);
});
}
verifiers.push(function verifyJsfunctionN(testlines) {
assert.equal(testlines.length, 2);
var parts = testlines[1].trim().split(/\s+/);
Expand Down Expand Up @@ -212,12 +228,19 @@ gcore.on('exit', function (code) {
mdb.stdin.write('::cat ' + tmpfile +
' | ::nodebuffer | ::eval "./ccccc"\n');

mdb.stdin.write('!echo test: v8internal\n');
mdb.stdin.write('::cat ' + tmpfile +
' | ::v8print ! awk \'$2 == "elements"{' +
'print $4 }\' > ' + tmpfile + '\n');
mdb.stdin.write('::cat ' + tmpfile + ' | ::v8internal 0\n');

// Buffer instances are implemented as typed arrays in Node
// versions that ship with V8 >= 4.6. Typed arrays in these versions
// of V8 do not *directly* store their underlying buffer as an
// "internal" element, so ::v8internal would not output its address.
// It would instead output the address of a FixedTypedArrayBase
// instance. Thus, skip the test.
if (V8_MAJOR < 4 || V8_MAJOR === 4 && V8_MINOR < 6) {
mdb.stdin.write('!echo test: v8internal\n');
mdb.stdin.write('::cat ' + tmpfile +
' | ::v8print ! awk \'$2 == "elements"{' +
'print $4 }\' > ' + tmpfile + '\n');
mdb.stdin.write('::cat ' + tmpfile + ' | ::v8internal 0\n');
}
mdb.stdin.write('!echo test: jsfunctions -n\n');
mdb.stdin.write('::jsfunctions -n myTestFunction ! cat\n');
mdb.stdin.write('!echo test: jsfunctions -s\n');
Expand Down