1
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function _typeof(obj) { if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }
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2
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3
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import { encodeNode } from "@webassemblyjs/wasm-gen";
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4
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import { overrideBytesInBuffer } from "@webassemblyjs/helper-buffer";
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5
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import constants from "@webassemblyjs/helper-wasm-bytecode";
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6
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import * as t from "@webassemblyjs/ast";
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7
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8
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function findLastSection(ast, forSection) {
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9
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var targetSectionId = constants.sections[forSection]; // $FlowIgnore: metadata can not be empty
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10
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11
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var moduleSections = ast.body[0].metadata.sections;
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12
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var lastSection;
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13
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var lastId = 0;
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14
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|
15
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for (var i = 0, len = moduleSections.length; i < len; i++) {
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16
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var section = moduleSections[i]; // Ignore custom section since they can actually occur everywhere
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17
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18
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if (section.section === "custom") {
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19
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continue;
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20
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}
|
21
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22
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var sectionId = constants.sections[section.section];
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23
|
|
24
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if (targetSectionId > lastId && targetSectionId < sectionId) {
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25
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return lastSection;
|
26
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}
|
27
|
|
28
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lastId = sectionId;
|
29
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lastSection = section;
|
30
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}
|
31
|
|
32
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return lastSection;
|
33
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}
|
34
|
|
35
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export function createEmptySection(ast, uint8Buffer, section) {
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36
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// previous section after which we are going to insert our section
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37
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var lastSection = findLastSection(ast, section);
|
38
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var start, end;
|
39
|
/**
|
40
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* It's the first section
|
41
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*/
|
42
|
|
43
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if (lastSection == null || lastSection.section === "custom") {
|
44
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start = 8
|
45
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/* wasm header size */
|
46
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;
|
47
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end = start;
|
48
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} else {
|
49
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start = lastSection.startOffset + lastSection.size.value + 1;
|
50
|
end = start;
|
51
|
} // section id
|
52
|
|
53
|
|
54
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start += 1;
|
55
|
var sizeStartLoc = {
|
56
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line: -1,
|
57
|
column: start
|
58
|
};
|
59
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var sizeEndLoc = {
|
60
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line: -1,
|
61
|
column: start + 1
|
62
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}; // 1 byte for the empty vector
|
63
|
|
64
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var size = t.withLoc(t.numberLiteralFromRaw(1), sizeEndLoc, sizeStartLoc);
|
65
|
var vectorOfSizeStartLoc = {
|
66
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line: -1,
|
67
|
column: sizeEndLoc.column
|
68
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};
|
69
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var vectorOfSizeEndLoc = {
|
70
|
line: -1,
|
71
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column: sizeEndLoc.column + 1
|
72
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};
|
73
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var vectorOfSize = t.withLoc(t.numberLiteralFromRaw(0), vectorOfSizeEndLoc, vectorOfSizeStartLoc);
|
74
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var sectionMetadata = t.sectionMetadata(section, start, size, vectorOfSize);
|
75
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var sectionBytes = encodeNode(sectionMetadata);
|
76
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uint8Buffer = overrideBytesInBuffer(uint8Buffer, start - 1, end, sectionBytes); // Add section into the AST for later lookups
|
77
|
|
78
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if (_typeof(ast.body[0].metadata) === "object") {
|
79
|
// $FlowIgnore: metadata can not be empty
|
80
|
ast.body[0].metadata.sections.push(sectionMetadata);
|
81
|
t.sortSectionMetadata(ast.body[0]);
|
82
|
}
|
83
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/**
|
84
|
* Update AST
|
85
|
*/
|
86
|
// Once we hit our section every that is after needs to be shifted by the delta
|
87
|
|
88
|
|
89
|
var deltaBytes = +sectionBytes.length;
|
90
|
var encounteredSection = false;
|
91
|
t.traverse(ast, {
|
92
|
SectionMetadata: function SectionMetadata(path) {
|
93
|
if (path.node.section === section) {
|
94
|
encounteredSection = true;
|
95
|
return;
|
96
|
}
|
97
|
|
98
|
if (encounteredSection === true) {
|
99
|
t.shiftSection(ast, path.node, deltaBytes);
|
100
|
}
|
101
|
}
|
102
|
});
|
103
|
return {
|
104
|
uint8Buffer: uint8Buffer,
|
105
|
sectionMetadata: sectionMetadata
|
106
|
};
|
107
|
}
|