Bug 1833385 - Call C++ function to flatten ropes in RegExp stubs. r=iain

On Speedometer 3, the most common reason for the stubs failing is rope input strings. We can avoid this by doing a `callWithABI` to a helper function to flatten the rope. Differential Revision: https://phabricator.services.mozilla.com/D178178
iaxat · May 17, 2023 · 8e95328 · 8e95328
1 parent e76581c
commit 8e95328
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Showing 2 changed files with 44 additions and 21 deletions.
diff --git a/js/src/jit-test/tests/regexp/rope-inputs.js b/js/src/jit-test/tests/regexp/rope-inputs.js
@@ -0,0 +1,10 @@
+function test() {
+    var re = /abc(.+)z/;
+    for (var i = 0; i < 100; i++) {
+        assertEq(re.exec(newRope("abcd", "xyz"))[1], "dxy");
+        assertEq(re.test(newRope("abcd", "xyz")), true);
+        assertEq(re[Symbol.search](newRope(".abcd", "xyz")), 1);
+        assertEq(re[Symbol.match](newRope("abcd", "xyz"))[1], "dxy");
+    }
+}
+test();
diff --git a/js/src/jit/CodeGenerator.cpp b/js/src/jit/CodeGenerator.cpp
@@ -2007,8 +2007,37 @@ static bool PrepareAndExecuteRegExp(JSContext* cx, MacroAssembler& masm,
   // Initialize MatchPairs::pairs[0]::start to MatchPair::NoMatch
   masm.store32(Imm32(MatchPair::NoMatch), firstMatchStartAddress);
 
-  // Check for a linear input string.
-  masm.branchIfRope(input, failure);
+  // Determine the set of volatile inputs to save when calling into C++ or
+  // regexp code.
+  LiveGeneralRegisterSet volatileRegs;
+  if (lastIndex.volatile_()) {
+    volatileRegs.add(lastIndex);
+  }
+  if (input.volatile_()) {
+    volatileRegs.add(input);
+  }
+  if (regexp.volatile_()) {
+    volatileRegs.add(regexp);
+  }
+
+  // Ensure the input string is not a rope.
+  Label isLinear;
+  masm.branchIfNotRope(input, &isLinear);
+  {
+    masm.PushRegsInMask(volatileRegs);
+
+    using Fn = JSLinearString* (*)(JSString*);
+    masm.setupUnalignedABICall(temp1);
+    masm.passABIArg(input);
+    masm.callWithABI<Fn, js::jit::LinearizeForCharAccessPure>();
+
+    MOZ_ASSERT(!volatileRegs.has(temp1));
+    masm.storeCallPointerResult(temp1);
+    masm.PopRegsInMask(volatileRegs);
+
+    masm.branchTestPtr(Assembler::Zero, temp1, temp1, failure);
+  }
+  masm.bind(&isLinear);
 
   // Load the RegExpShared.
   Register regexpReg = temp1;
@@ -2023,14 +2052,9 @@ static bool PrepareAndExecuteRegExp(JSContext* cx, MacroAssembler& masm,
                  Address(regexpReg, RegExpShared::offsetOfPatternAtom()),
                  ImmWord(0), &notAtom);
   {
-    LiveGeneralRegisterSet regsToSave(GeneralRegisterSet::Volatile());
-    regsToSave.takeUnchecked(temp1);
-    regsToSave.takeUnchecked(temp2);
-    regsToSave.takeUnchecked(temp3);
-
     masm.computeEffectiveAddress(matchPairsAddress, temp3);
 
-    masm.PushRegsInMask(regsToSave);
+    masm.PushRegsInMask(volatileRegs);
     using Fn = RegExpRunStatus (*)(RegExpShared* re, JSLinearString* input,
                                    size_t start, MatchPairs* matchPairs);
     masm.setupUnalignedABICall(temp2);
@@ -2040,8 +2064,9 @@ static bool PrepareAndExecuteRegExp(JSContext* cx, MacroAssembler& masm,
     masm.passABIArg(temp3);
     masm.callWithABI<Fn, js::ExecuteRegExpAtomRaw>();
 
+    MOZ_ASSERT(!volatileRegs.has(temp1));
     masm.storeCallInt32Result(temp1);
-    masm.PopRegsInMask(regsToSave);
+    masm.PopRegsInMask(volatileRegs);
 
     masm.jump(&checkSuccess);
   }
@@ -2104,18 +2129,6 @@ static bool PrepareAndExecuteRegExp(JSContext* cx, MacroAssembler& masm,
   masm.storePtr(temp2, matchesAddress);
   masm.storePtr(lastIndex, startIndexAddress);
 
-  // Save any volatile inputs.
-  LiveGeneralRegisterSet volatileRegs;
-  if (lastIndex.volatile_()) {
-    volatileRegs.add(lastIndex);
-  }
-  if (input.volatile_()) {
-    volatileRegs.add(input);
-  }
-  if (regexp.volatile_()) {
-    volatileRegs.add(regexp);
-  }
-
   // Execute the RegExp.
   masm.computeEffectiveAddress(
       Address(FramePointer, inputOutputDataStartOffset), temp2);