Mozilla bug 1998923 - Make better inline and never-inline decisions around EnsureBufferSpace in the tokenizer. r=farre

Differential Revision: https://phabricator.services.mozilla.com/D271752

Author: hsivonen

src/nu/validator/htmlparser/impl/Portability.java

@@ -31,6 +31,7 @@
 
 public final class Portability {
 
+    // [NOCPP[
     public static int checkedAdd(int a, int b) throws SAXException {
         // This can't be translated code, because in C++ signed integer overflow is UB, so the below code would be wrong.
         assert a >= 0;
@@ -41,6 +42,7 @@ public static int checkedAdd(int a, int b) throws SAXException {
         }
         return sum;
     }
+    // ]NOCPP]
 
     // Allocating methods
 

src/nu/validator/htmlparser/impl/Tokenizer.java

@@ -982,12 +982,9 @@ private void emitOrAppendCharRefBuf(int returnState) throws SAXException {
      * @param c
      *            the UTF-16 code unit to append
      */
-    private void appendStrBuf(char c) {
-        // CPPONLY: assert strBufLen < strBuf.length: "Previous buffer length insufficient.";
+    @Inline private void appendStrBuf(char c) {
         // CPPONLY: if (strBufLen == strBuf.length) {
-        // CPPONLY:     if (!EnsureBufferSpace(1)) {
-        // CPPONLY:         assert false: "RELEASE: Unable to recover from buffer reallocation failure";
-        // CPPONLY:     } // TODO: Add telemetry when outer if fires but inner does not
+        // CPPONLY:     EnsureBufferSpaceShouldNeverHappen(1);
         // CPPONLY: }
         strBuf[strBufLen++] = c;
     }
@@ -1094,13 +1091,12 @@ private void maybeAppendSpaceToBogusComment() throws SAXException {
         // ]NOCPP]
     }
 
-    private void appendStrBuf(@NoLength char[] buffer, int offset, int length) throws SAXException {
-        int newLen = Portability.checkedAdd(strBufLen, length);
-        // CPPONLY: assert newLen <= strBuf.length: "Previous buffer length insufficient.";
+    @Inline private void appendStrBuf(@NoLength char[] buffer, int offset, int length) throws SAXException {
+        // Years of crash stats have shown that the this addition doesn't overflow, as it logically
+        // shouldn't.
+        int newLen = strBufLen + length;
         // CPPONLY: if (strBuf.length < newLen) {
-        // CPPONLY:     if (!EnsureBufferSpace(length)) {
-        // CPPONLY:         assert false: "RELEASE: Unable to recover from buffer reallocation failure";
-        // CPPONLY:     } // TODO: Add telemetry when outer if fires but inner does not
+        // CPPONLY:     EnsureBufferSpaceShouldNeverHappen(length);
         // CPPONLY: }
         System.arraycopy(buffer, offset, strBuf, strBufLen, length);
         strBufLen = newLen;