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perf(endpoints): Add peephole optimizations to endpoint resolution codegen
Add compile-time peephole optimizations to both BDD and Rules endpoint resolver code generation that eliminate unnecessary allocations and method dispatch overhead: 1. coalesce+substring → startsWith/endsWith/regionMatches 2. ite(cond, a, b) → inline ternary (cond ? a : b) 3. coalesce(boolExpr, default) → inline null-check 4. stringEquals → .equals() unconditionally 5. Dead null-check elimination on ite assigns 6. Endpoint.of(EndpointUrl) zero-attribute factory 7. isValidHostLabel → isValidHostLabelSingle/Multi specialization 8. StringConcatExpression parenthesization for .equals() source
1 parent d5f508e commit 0269d85

10 files changed

Lines changed: 761 additions & 18 deletions

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‎codegen/src/main/java/software/amazon/awssdk/codegen/poet/rules2/CodeGeneratorVisitor.java‎

Lines changed: 157 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -109,6 +109,13 @@ public Void visitFunctionCallExpression(FunctionCallExpression e) {
109109
builder.add(" == null");
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return null;
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}
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// Peephole-optimized synthetic functions
114+
if (fn.startsWith("__")) {
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emitPeepholeOptimized(fn, e.arguments());
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return null;
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}
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RuleFunctionMirror func = typeMirror.resolveFunction(e.name());
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builder.add("$T.$L(", func.containingType().type(), func.javaName());
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List<RuleExpression> args = e.arguments();
@@ -124,9 +131,152 @@ public Void visitFunctionCallExpression(FunctionCallExpression e) {
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return null;
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}
126133

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/**
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* Emits peephole-optimized native Java code for synthetic function calls.
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* These avoid allocations by using String.startsWith/endsWith/regionMatches
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* and inline ternary expressions instead of calling RulesFunctions.
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*/
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private void emitPeepholeOptimized(String fn, List<RuleExpression> args) {
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switch (fn) {
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case PrepareForCodegenVisitor.STARTS_WITH:
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emitStartsWith(args);
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break;
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case PrepareForCodegenVisitor.ENDS_WITH:
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emitEndsWith(args);
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break;
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case PrepareForCodegenVisitor.REGION_MATCHES:
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emitRegionMatches(args);
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break;
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case PrepareForCodegenVisitor.ITE:
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emitIte(args);
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break;
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case PrepareForCodegenVisitor.COALESCE_BOOL:
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emitCoalesceBoolean(args);
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break;
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case PrepareForCodegenVisitor.IS_VALID_HOST_LABEL:
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emitIsValidHostLabel(args);
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break;
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default:
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throw new IllegalStateException("Unknown peephole function: " + fn);
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}
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}
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/**
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* Emits: {@code (str != null && str.startsWith("literal"))}
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*/
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private void emitStartsWith(List<RuleExpression> args) {
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builder.add("(");
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args.get(0).accept(this);
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builder.add(" != null && ");
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args.get(0).accept(this);
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builder.add(".startsWith(");
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args.get(1).accept(this);
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builder.add("))");
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}
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/**
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* Emits: {@code (str != null && str.endsWith("literal"))}
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*/
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private void emitEndsWith(List<RuleExpression> args) {
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builder.add("(");
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args.get(0).accept(this);
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builder.add(" != null && ");
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args.get(0).accept(this);
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builder.add(".endsWith(");
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args.get(1).accept(this);
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builder.add("))");
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}
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/**
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* Emits a regionMatches check. Offset can be negative to indicate "from end" (reverse=true).
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* <ul>
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* <li>Positive offset: {@code (str != null && str.length() >= (offset + litLen)
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* && str.regionMatches(offset, "literal", 0, litLen))}</li>
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* <li>Negative offset (value = -stopIdx): {@code (str != null && str.length() >= stopIdx
196+
* && str.regionMatches(str.length() - stopIdx, "literal", 0, litLen))}</li>
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* </ul>
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*/
199+
private void emitRegionMatches(List<RuleExpression> args) {
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RuleExpression strExpr = args.get(0);
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int offset = ((LiteralIntegerExpression) args.get(1)).value();
202+
String literal = ((LiteralStringExpression) args.get(2)).value();
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int litLen = literal.length();
204+
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builder.add("(");
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strExpr.accept(this);
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builder.add(" != null && ");
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209+
if (offset >= 0) {
210+
// Forward: str.length() >= (offset + litLen) && str.regionMatches(offset, literal, 0, litLen)
211+
strExpr.accept(this);
212+
builder.add(".length() >= $L && ", offset + litLen);
213+
strExpr.accept(this);
214+
builder.add(".regionMatches(");
215+
builder.add("$L, $S, 0, $L", offset, literal, litLen);
216+
builder.add("))");
217+
} else {
218+
// Reverse: offset encodes -(stopIdx). Actual position = str.length() - stopIdx
219+
int stopIdx = -offset;
220+
strExpr.accept(this);
221+
builder.add(".length() >= $L && ", stopIdx);
222+
strExpr.accept(this);
223+
builder.add(".regionMatches(");
224+
strExpr.accept(this);
225+
builder.add(".length() - $L, $S, 0, $L", stopIdx, literal, litLen);
226+
builder.add("))");
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}
228+
}
229+
230+
/**
231+
* Emits: {@code (cond ? ifTrue : ifFalse)}
232+
*/
233+
private void emitIte(List<RuleExpression> args) {
234+
builder.add("(");
235+
args.get(0).accept(this);
236+
builder.add(" ? ");
237+
args.get(1).accept(this);
238+
builder.add(" : ");
239+
args.get(2).accept(this);
240+
builder.add(")");
241+
}
242+
243+
/**
244+
* Emits: {@code (expr != null ? expr : defaultValue)}
245+
*/
246+
private void emitCoalesceBoolean(List<RuleExpression> args) {
247+
builder.add("(");
248+
args.get(0).accept(this);
249+
builder.add(" != null ? ");
250+
args.get(0).accept(this);
251+
builder.add(" : ");
252+
args.get(1).accept(this);
253+
builder.add(")");
254+
}
255+
256+
/**
257+
* Emits: {@code RulesFunctions.isValidHostLabelSingle(str)} or
258+
* {@code RulesFunctions.isValidHostLabelMulti(str)}
259+
*/
260+
private void emitIsValidHostLabel(List<RuleExpression> args) {
261+
boolean allowDots = ((LiteralBooleanExpression) args.get(1)).value();
262+
RuleFunctionMirror func = typeMirror.resolveFunction("isValidHostLabel");
263+
builder.add("$T.$L(", func.containingType().type(),
264+
allowDots ? "isValidHostLabelMulti" : "isValidHostLabelSingle");
265+
args.get(0).accept(this);
266+
builder.add(")");
267+
}
268+
127269
@Override
128270
public Void visitMethodCallExpression(MethodCallExpression e) {
271+
// Wrap compound expressions (string concat) in parens to ensure correct binding
272+
boolean needsParens = e.source().kind() == RuleExpression.RuleExpressionKind.STRING_CONCAT;
273+
if (needsParens) {
274+
builder.add("(");
275+
}
129276
e.source().accept(this);
277+
if (needsParens) {
278+
builder.add(")");
279+
}
130280
builder.add(".$L(", e.name());
131281
boolean isFirst = true;
132282
for (RuleExpression arg : e.arguments()) {
@@ -330,10 +480,16 @@ private String callParams(String ruleId) {
330480
public Void visitEndpointExpression(EndpointExpression e) {
331481
Map<String, RuleExpression> properties = e.properties().properties();
332482
boolean hasHeaders = !e.headers().headers().isEmpty();
483+
boolean hasNoAttributes = !hasHeaders && properties.isEmpty();
333484
boolean hasAuthSchemesOnly = !hasHeaders && properties.size() == 1 && properties.containsKey("authSchemes");
334485
boolean hasTwoAttrs = !hasHeaders && properties.size() == 2 && properties.containsKey("authSchemes");
335486

336-
if (hasAuthSchemesOnly) {
487+
if (hasNoAttributes) {
488+
// Most optimized: Endpoint.of(url) — no attributes, no headers, no builder allocation
489+
builder.add("return $T.of(", Endpoint.class);
490+
EndpointUrlCodeEmitter.emit(e.url(), builder, this);
491+
builder.addStatement(")");
492+
} else if (hasAuthSchemesOnly) {
337493
// Optimized: Endpoint.ofAttribute(url, AUTH_SCHEMES, list)
338494
builder.add("return $T.ofAttribute(", Endpoint.class);
339495
EndpointUrlCodeEmitter.emit(e.url(), builder, this);

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