Add control flow complexity limiter

src/compiler/checker.ts

@@ -540,7 +540,8 @@ namespace ts {
         let flowLoopStart = 0;
         let flowLoopCount = 0;
         let sharedFlowCount = 0;
-        let flowAnalysisDisabled = false;
+        let flowNodeCount = -1;
+        let flowAnalysisErrors = false;
 
         const emptyStringType = getLiteralType("");
         const zeroType = getLiteralType(0);
@@ -15949,17 +15950,14 @@ namespace ts {
             return false;
         }
 
-        function reportFlowControlError(node: Node) {
-            const block = <Block | ModuleBlock | SourceFile>findAncestor(node, isFunctionOrModuleBlock);
-            const sourceFile = getSourceFileOfNode(node);
-            const span = getSpanOfTokenAtPosition(sourceFile, block.statements.pos);
-            diagnostics.add(createFileDiagnostic(sourceFile, span.start, span.length, Diagnostics.The_containing_function_or_module_body_is_too_large_for_control_flow_analysis));
+        function getContainingBlock(node: Node) {
+            return <Block | ModuleBlock | SourceFile>findAncestor(node, isFunctionOrModuleBlock);
         }
 
         function getFlowTypeOfReference(reference: Node, declaredType: Type, initialType = declaredType, flowContainer?: Node, couldBeUninitialized?: boolean) {
             let key: string | undefined;
             let flowDepth = 0;
-            if (flowAnalysisDisabled) {
+            if (flowAnalysisErrors && getNodeLinks(getContainingBlock(reference)).flags & NodeCheckFlags.FlowAnalysisError) {
                 return errorType;
             }
             if (!reference.flowNode || !couldBeUninitialized && !(declaredType.flags & TypeFlags.Narrowable)) {
@@ -15979,14 +15977,23 @@ namespace ts {
             return resultType;
 
             function getTypeAtFlowNode(flow: FlowNode): FlowType {
-                if (flowDepth === 2000) {
-                    // We have made 2000 recursive invocations. To avoid overflowing the call stack we report an error
-                    // and disable further control flow analysis in the containing function or module body.
-                    flowAnalysisDisabled = true;
-                    reportFlowControlError(reference);
+                if (flowDepth === 2000 || flowNodeCount === 500000) {
+                    // We have made 2000 recursive invocations or visited 500000 control flow nodes while analyzing
+                    // the containing function or module body, the limit at which we consider the function or module
+                    // body is too complex and disable further control flow analysis.
+                    const block = getContainingBlock(reference);
+                    const nodeLinks = getNodeLinks(block);
+                    if (!(nodeLinks.flags & NodeCheckFlags.FlowAnalysisError)) {
+                        nodeLinks.flags |= NodeCheckFlags.FlowAnalysisError;
+                        const sourceFile = getSourceFileOfNode(block);
+                        const span = getSpanOfTokenAtPosition(sourceFile, block.statements.pos);
+                        diagnostics.add(createFileDiagnostic(sourceFile, span.start, span.length, Diagnostics.The_containing_function_or_module_body_is_too_complex_for_control_flow_analysis));
+                        flowAnalysisErrors = true;
+                    }
                     return errorType;
                 }
                 flowDepth++;
+                if (flowNodeCount >= 0) flowNodeCount++;
                 while (true) {
                     const flags = flow.flags;
                     if (flags & FlowFlags.Shared) {
@@ -26026,9 +26033,10 @@ namespace ts {
                 checkGrammarStatementInAmbientContext(node);
             }
             if (isFunctionOrModuleBlock(node)) {
-                const saveFlowAnalysisDisabled = flowAnalysisDisabled;
+                const saveFlowNodeCount = flowNodeCount;
+                flowNodeCount = 0;
                 forEach(node.statements, checkSourceElement);
-                flowAnalysisDisabled = saveFlowAnalysisDisabled;
+                flowNodeCount = saveFlowNodeCount;
             }
             else {
                 forEach(node.statements, checkSourceElement);
@@ -28861,7 +28869,9 @@ namespace ts {
 
         function checkSourceFile(node: SourceFile) {
             performance.mark("beforeCheck");
+            flowNodeCount = 0;
             checkSourceFileWorker(node);
+            flowNodeCount = -1;
             performance.mark("afterCheck");
             performance.measure("Check", "beforeCheck", "afterCheck");
         }

src/compiler/diagnosticMessages.json

@@ -2044,7 +2044,7 @@
         "category": "Error",
         "code": 2562
     },
-    "The containing function or module body is too large for control flow analysis.": {
+    "The containing function or module body is too complex for control flow analysis.": {
         "category": "Error",
         "code": 2563
     },

src/compiler/types.ts

@@ -3855,6 +3855,7 @@ namespace ts {
         AssignmentsMarked                   = 0x00800000,  // Parameter assignments have been marked
         ClassWithConstructorReference       = 0x01000000,  // Class that contains a binding to its constructor inside of the class body.
         ConstructorReferenceInClass         = 0x02000000,  // Binding to a class constructor inside of the class's body.
+        FlowAnalysisError                   = 0x04000000,  // Control flow analysis error in this block
     }
 
     /* @internal */

tests/baselines/reference/complexControlFlowGraph.errors.txt

@@ -0,0 +1,163 @@
+tests/cases/compiler/complexControlFlowGraph.ts(4,3): error TS2563: The containing function or module body is too complex for control flow analysis.
+
+
+==== tests/cases/compiler/complexControlFlowGraph.ts (1 errors) ====
+    // Repro from #29926
+
+    const foo = function (this: any) {
+      var a, b, c, d, ab, bc, cd, da, blocks = this.blocks;
+      ~~~
+!!! error TS2563: The containing function or module body is too complex for control flow analysis.
+
+      if (this.first) {
+        a = blocks[0] - 1;
+        a = (a << 3) | (a >>> 29);
+        d = ((a & 0xefcdab89) | (~a & 0x98badcfe)) + blocks[1] + 271733878;
+        d = (d << 7) | (d >>> 25);
+        c = ((d & a) | (~d & 0xefcdab89)) + blocks[2] - 1732584194;
+        c = (c << 11) | (c >>> 21);
+        b = ((c & d) | (~c & a)) + blocks[3] - 271733879;
+        b = (b << 19) | (b >>> 13);
+      } else {
+        a = this.h0;
+        b = this.h1;
+        c = this.h2;
+        d = this.h3;
+        a += ((b & c) | (~b & d)) + blocks[0];
+        a = (a << 3) | (a >>> 29);
+        d += ((a & b) | (~a & c)) + blocks[1];
+        d = (d << 7) | (d >>> 25);
+        c += ((d & a) | (~d & b)) + blocks[2];
+        c = (c << 11) | (c >>> 21);
+        b += ((c & d) | (~c & a)) + blocks[3];
+        b = (b << 19) | (b >>> 13);
+      }
+
+      a += ((b & c) | (~b & d)) + blocks[4];
+      a = (a << 3) | (a >>> 29);
+      d += ((a & b) | (~a & c)) + blocks[5];
+      d = (d << 7) | (d >>> 25);
+      c += ((d & a) | (~d & b)) + blocks[6];
+      c = (c << 11) | (c >>> 21);
+      b += ((c & d) | (~c & a)) + blocks[7];
+      b = (b << 19) | (b >>> 13);
+      a += ((b & c) | (~b & d)) + blocks[8];
+      a = (a << 3) | (a >>> 29);
+      d += ((a & b) | (~a & c)) + blocks[9];
+      d = (d << 7) | (d >>> 25);
+      c += ((d & a) | (~d & b)) + blocks[10];
+      c = (c << 11) | (c >>> 21);
+      b += ((c & d) | (~c & a)) + blocks[11];
+      b = (b << 19) | (b >>> 13);
+      a += ((b & c) | (~b & d)) + blocks[12];
+      a = (a << 3) | (a >>> 29);
+      d += ((a & b) | (~a & c)) + blocks[13];
+      d = (d << 7) | (d >>> 25);
+      c += ((d & a) | (~d & b)) + blocks[14];
+      c = (c << 11) | (c >>> 21);
+      b += ((c & d) | (~c & a)) + blocks[15];
+      b = (b << 19) | (b >>> 13);
+
+      bc = b & c;
+      a += (bc | (b & d) | (c & d)) + blocks[0] + 1518500249;
+      a = (a << 3) | (a >>> 29);
+      ab = a & b;
+      d += (ab | (a & c) | bc) + blocks[4] + 1518500249;
+      d = (d << 5) | (d >>> 27);
+      da = d & a;
+      c += (da | (d & b) | ab) + blocks[8] + 1518500249;
+      c = (c << 9) | (c >>> 23);
+      cd = c & d;
+      b += (cd | (c & a) | da) + blocks[12] + 1518500249;
+      b = (b << 13) | (b >>> 19);
+      bc = b & c;
+      a += (bc | (b & d) | cd) + blocks[1] + 1518500249;
+      a = (a << 3) | (a >>> 29);
+      ab = a & b;
+      d += (ab | (a & c) | bc) + blocks[5] + 1518500249;
+      d = (d << 5) | (d >>> 27);
+      da = d & a;
+      c += (da | (d & b) | ab) + blocks[9] + 1518500249;
+      c = (c << 9) | (c >>> 23);
+      cd = c & d;
+      b += (cd | (c & a) | da) + blocks[13] + 1518500249;
+      b = (b << 13) | (b >>> 19);
+      bc = b & c;
+      a += (bc | (b & d) | cd) + blocks[2] + 1518500249;
+      a = (a << 3) | (a >>> 29);
+      ab = a & b;
+      d += (ab | (a & c) | bc) + blocks[6] + 1518500249;
+      d = (d << 5) | (d >>> 27);
+      da = d & a;
+      c += (da | (d & b) | ab) + blocks[10] + 1518500249;
+      c = (c << 9) | (c >>> 23);
+      cd = c & d;
+      b += (cd | (c & a) | da) + blocks[14] + 1518500249;
+      b = (b << 13) | (b >>> 19);
+      bc = b & c;
+      a += (bc | (b & d) | cd) + blocks[3] + 1518500249;
+      a = (a << 3) | (a >>> 29);
+      ab = a & b;
+      d += (ab | (a & c) | bc) + blocks[7] + 1518500249;
+      d = (d << 5) | (d >>> 27);
+      da = d & a;
+      c += (da | (d & b) | ab) + blocks[11] + 1518500249;
+      c = (c << 9) | (c >>> 23);
+      b += ((c & d) | (c & a) | da) + blocks[15] + 1518500249;
+      b = (b << 13) | (b >>> 19);
+
+      bc = b ^ c;
+      a += (bc ^ d) + blocks[0] + 1859775393;
+      a = (a << 3) | (a >>> 29);
+      d += (bc ^ a) + blocks[8] + 1859775393;
+      d = (d << 9) | (d >>> 23);
+      da = d ^ a;
+      c += (da ^ b) + blocks[4] + 1859775393;
+      c = (c << 11) | (c >>> 21);
+      b += (da ^ c) + blocks[12] + 1859775393;
+      b = (b << 15) | (b >>> 17);
+      bc = b ^ c;
+      a += (bc ^ d) + blocks[2] + 1859775393;
+      a = (a << 3) | (a >>> 29);
+      d += (bc ^ a) + blocks[10] + 1859775393;
+      d = (d << 9) | (d >>> 23);
+      da = d ^ a;
+      c += (da ^ b) + blocks[6] + 1859775393;
+      c = (c << 11) | (c >>> 21);
+      b += (da ^ c) + blocks[14] + 1859775393;
+      b = (b << 15) | (b >>> 17);
+      bc = b ^ c;
+      a += (bc ^ d) + blocks[1] + 1859775393;
+      a = (a << 3) | (a >>> 29);
+      d += (bc ^ a) + blocks[9] + 1859775393;
+      d = (d << 9) | (d >>> 23);
+      da = d ^ a;
+      c += (da ^ b) + blocks[5] + 1859775393;
+      c = (c << 11) | (c >>> 21);
+      b += (da ^ c) + blocks[13] + 1859775393;
+      b = (b << 15) | (b >>> 17);
+      bc = b ^ c;
+      a += (bc ^ d) + blocks[3] + 1859775393;
+      a = (a << 3) | (a >>> 29);
+      d += (bc ^ a) + blocks[11] + 1859775393;
+      d = (d << 9) | (d >>> 23);
+      da = d ^ a;
+      c += (da ^ b) + blocks[7] + 1859775393;
+      c = (c << 11) | (c >>> 21);
+      b += (da ^ c) + blocks[15] + 1859775393;
+      b = (b << 15) | (b >>> 17);
+
+      if (this.first) {
+        this.h0 = a + 1732584193 << 0;
+        this.h1 = b - 271733879 << 0;
+        this.h2 = c - 1732584194 << 0;
+        this.h3 = d + 271733878 << 0;
+        this.first = false;
+      } else {
+        this.h0 = this.h0 + a << 0;
+        this.h1 = this.h1 + b << 0;
+        this.h2 = this.h2 + c << 0;
+        this.h3 = this.h3 + d << 0;
+      }
+    };
+