Merge pull request github#12285 from github/calumgrant/ql-ra-parser

RA parser first draft

Author: MathiasVP

ql/ql/src/experimental/RA.qll

@@ -0,0 +1,111 @@
+/**
+ * Parses RA expressions.
+ */
+
+/**
+ * A predicate that contains RA.
+ */
+signature class RApredicate {
+  string getLineOfRA(int n);
+}
+
+/**
+ * Parses strings of RA provided by an RA predicate, and represented the
+ */
+module RAParser<RApredicate Predicate> {
+  private string parseRaExpr(Predicate p, int line, int arity, int lhs) {
+    exists(string str | str = p.getLineOfRA(line).trim() |
+      arity = str.regexpCapture("\\{([0-9]+)\\} r([0-9]+) = (.+)", 1).toInt() and
+      lhs = str.regexpCapture("\\{([0-9]+)\\} r([0-9]+) = (.+)", 2).toInt() and
+      result = str.regexpCapture("\\{([0-9]+)\\} r([0-9]+) = (.+)", 3)
+    )
+  }
+
+  bindingset[str]
+  private int parseReturn(string str) {
+    result = str.trim().regexpCapture("return r([0-9]+)", 1).toInt()
+  }
+
+  private newtype TRA =
+    TReturn(Predicate p, int line, int v) { v = parseReturn(p.getLineOfRA(line)) } or
+    TUnknown(Predicate p, int line, int lhs, int arity, string rhs) {
+      rhs = parseRaExpr(p, line, arity, lhs)
+    }
+
+  /** An RA Expression. */
+  abstract class RAExpr extends TRA {
+    /** Gets the predicate this RA expression belongs to. */
+    abstract Predicate getPredicate();
+
+    /** Gets the line index of this RA expression. */
+    abstract int getLine();
+
+    /** Gets the LHS of the expression of the form `rNN = ...` */
+    abstract int getLhs();
+
+    /** Gets a variable of the form `rNN` in the RHS of the RA expression. */
+    abstract int getARhsVariable();
+
+    /** Gets the given arity of the RA expression. */
+    abstract int getArity();
+
+    /** Gets a predicate name referenced in the RHS of an RA expression. */
+    abstract string getARhsPredicate();
+
+    final string toString() { result = this.getPredicate().getLineOfRA(this.getLine()) }
+
+    /** Gets a child of this RA expression - not by index yet. */
+    RAExpr getAChild() {
+      result.getPredicate() = this.getPredicate() and result.getLhs() = this.getARhsVariable()
+    }
+  }
+
+  /**
+   * A generic RA expression - where we haven't precisely parsed the RA expression type.
+   * For Hackathon purposes, we probably don't need more than this.
+   */
+  class RAUnknownExpr extends RAExpr, TUnknown {
+    Predicate p;
+    int line;
+    string rhs;
+    int arity;
+    int lhs;
+
+    RAUnknownExpr() { this = TUnknown(p, line, lhs, arity, rhs) }
+
+    override int getLine() { result = line }
+
+    override Predicate getPredicate() { result = p }
+
+    override int getLhs() { result = lhs }
+
+    override int getARhsVariable() {
+      result = rhs.splitAt(" ").regexpCapture("r([0-9]+)", 1).toInt()
+    }
+
+    // This is a dumb regex to find a predicate name - they always contain a `#` (TODO...)
+    override string getARhsPredicate() { result = rhs.splitAt(" ") and result.indexOf("#") > 0 }
+
+    override int getArity() { result = arity }
+  }
+
+  class RAReturnExpr extends RAExpr, TReturn {
+    RAReturnExpr() { this = TReturn(p, line, res) }
+
+    Predicate p;
+    int line;
+    int res;
+
+    override Predicate getPredicate() { result = p }
+
+    override int getLine() { result = line }
+
+    override int getLhs() { none() }
+
+    override int getARhsVariable() { result = res }
+
+    override int getArity() { none() }
+
+    override string getARhsPredicate() { none() }
+  }
+}

ql/ql/test/experimental/raparser.expected

@@ -0,0 +1,17 @@
+children
+|     return r7 |     {4} r7 = r3 UNION r6 |
+|     {4} r2 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT "p1", toString("p1"), 123, "  r1 = SCAN fubar\\n   r1" |     {1} r1 = CONSTANT(unique string)["p1"] |
+|     {4} r3 = STREAM DEDUP r2 |     {4} r2 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT "p1", toString("p1"), 123, "  r1 = SCAN fubar\\n   r1" |
+|     {4} r4 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT "p1", "(no string representation)", 123, "  r1 = SCAN fubar\\n   r1" |     {1} r1 = CONSTANT(unique string)["p1"] |
+|     {4} r5 = STREAM DEDUP r4 |     {4} r4 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT "p1", "(no string representation)", 123, "  r1 = SCAN fubar\\n   r1" |
+|     {4} r6 = r5 AND NOT project##select#query#ffff#nullary({}) |     {4} r5 = STREAM DEDUP r4 |
+|     {4} r7 = r3 UNION r6 |     {4} r3 = STREAM DEDUP r2 |
+|     {4} r7 = r3 UNION r6 |     {4} r6 = r5 AND NOT project##select#query#ffff#nullary({}) |
+#select
+| p1 | 1 |     {1} r1 = CONSTANT(unique string)["p1"] | 1 | 1 | 0 | 0 |
+| p1 | 3 |     {4} r2 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT "p1", toString("p1"), 123, "  r1 = SCAN fubar\\n   r1" | 2 | 4 | 1 | 1 |
+| p1 | 5 |     {4} r3 = STREAM DEDUP r2 | 3 | 4 | 0 | 1 |
+| p1 | 6 |     {4} r4 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT "p1", "(no string representation)", 123, "  r1 = SCAN fubar\\n   r1" | 4 | 4 | 1 | 1 |
+| p1 | 7 |     {4} r5 = STREAM DEDUP r4 | 5 | 4 | 0 | 1 |
+| p1 | 8 |     {4} r6 = r5 AND NOT project##select#query#ffff#nullary({}) | 6 | 4 | 1 | 1 |
+| p1 | 9 |     {4} r7 = r3 UNION r6 | 7 | 4 | 0 | 2 |

ql/ql/test/experimental/raparser.ql

@@ -0,0 +1,42 @@
+import experimental.RA
+
+class TestPredicate extends string {
+  TestPredicate() { this = "p1" }
+
+  string getLineOfRA(int line) {
+    line = 1 and
+    result = "    {1} r1 = CONSTANT(unique string)[\"p1\"]"
+    or
+    line = 2 and result = ""
+    or
+    line = 3 and
+    result =
+      "    {4} r2 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT \"p1\", toString(\"p1\"), 123, \"  r1 = SCAN fubar\\n   r1\""
+    or
+    line = 4 and result = ""
+    or
+    line = 5 and result = "    {4} r3 = STREAM DEDUP r2"
+    or
+    line = 6 and
+    result =
+      "    {4} r4 = JOIN r1 WITH raparser#d14bb8db::TestPredicate#b ON FIRST 1 OUTPUT \"p1\", \"(no string representation)\", 123, \"  r1 = SCAN fubar\\n   r1\""
+    or
+    line = 7 and result = "    {4} r5 = STREAM DEDUP r4"
+    or
+    line = 8 and result = "    {4} r6 = r5 AND NOT project##select#query#ffff#nullary({})"
+    or
+    line = 9 and result = "    {4} r7 = r3 UNION r6"
+    or
+    line = 10 and result = "    return r7"
+  }
+}
+
+query predicate children(
+  RAParser<TestPredicate>::RAExpr parent, RAParser<TestPredicate>::RAExpr child
+) {
+  child = parent.getAChild()
+}
+
+from RAParser<TestPredicate>::RAExpr expr
+select expr.getPredicate(), expr.getLine(), expr, expr.getLhs(), expr.getArity(),
+  count(expr.getARhsPredicate()), count(expr.getARhsVariable())