Enable Scoped Variables

Author: CodaFi

Sources/FileCheck/FileCheck.swift

@@ -27,6 +27,10 @@ public struct FileCheckOptions: OptionSet {
   public static let matchFullLines = FileCheckOptions(rawValue: 1 << 2)
   /// Disable colored diagnostics.
   public static let disableColors = FileCheckOptions(rawValue: 1 << 3)
+  /// Enables scoping for variables defined in patterns.  Variables with names
+  /// that do not start with `$` will be reset at the beginning of each
+  /// `CHECK-LABEL` block.
+  public static let scopedVariables = FileCheckOptions(rawValue: 1 << 4)
 }
 
 /// `FileCheckFD` represents the standard output streams `FileCheck` is capable
@@ -558,6 +562,20 @@ private func check(
       j += 1
     }
 
+    // Remove local variables from the variable table. Global variables
+    // (start with `$`) are preserved.
+    if options.contains(.scopedVariables) {
+      var localVariables = [String]()
+      localVariables.reserveCapacity(16)
+      for (k, v) in variableTable where !k.hasPrefix("$") {
+        localVariables.append(k)
+      }
+
+      for k in localVariables {
+        variableTable.removeValue(forKey: k)
+      }
+    }
+
     while i != j {
       defer { i += 1 }
 

Sources/FileCheck/Pattern.swift

@@ -186,13 +186,20 @@ final class Pattern {
         var isExpression = false
         let diagLoc = CheckLocation.inBuffer(pattern.baseAddress!, buf)
         for (i, c) in name.enumerated() {
-          if i == 0 && c == "@" {
-            if nameEnd != nil {
-              diagnose(.error, at: diagLoc, with: "invalid name in named regex definition", options: options)
-              return nil
+          if i == 0 {
+            // Global vars start with '$'
+            if c == "$" {
+              continue
+            }
+
+            if c == "@" {
+              if nameEnd != nil {
+                diagnose(.error, at: diagLoc, with: "invalid name in named regex definition", options: options)
+                return nil
+              }
+              isExpression = true
+              continue
             }
-            isExpression = true
-            continue
           }
           if c != "_" && isalnum(Int32(c.utf8CodePoint)) == 0 && (!isExpression || (c != "+" && c != "-")) {
             diagnose(.error, at: diagLoc, with: "invalid name in named regex", options: options)

Tests/FileCheckTests/DefinesSpec.swift

@@ -3,7 +3,7 @@ import XCTest
 import Foundation
 
 class DefinesSpec : XCTestCase {
-  func testEnvironmentVariables() {
+  func testGlobalDefines() {
     XCTAssert(fileCheckOutput(of: .stdout, withPrefixes: ["PASSDEF"], withGlobals: ["VALUE":"10"]) {
       // PASSDEF: Value = [[VALUE]]
       print("Value = 10")
@@ -19,5 +19,11 @@ class DefinesSpec : XCTestCase {
       })
     })
   }
+
+  #if !os(macOS)
+  static var allTests = testCase([
+    ("testGlobalDefines", testGlobalDefines),
+  ])
+  #endif
 }
 

Tests/FileCheckTests/RegexScopeSpec.swift

@@ -0,0 +1,43 @@
+import FileCheck
+import XCTest
+import Foundation
+
+class RegexScopeSpec : XCTestCase {
+  func testRegexScope() {
+    let block = { () -> () in
+      // CHECK: [[LOCAL:loc.*]]
+      // CHECK: [[$GLOBAL:glo.*]]
+      print("""
+            local
+            global
+            """)
+      // CHECK: [[LOCAL]]2
+      // CHECK: [[$GLOBAL]]2
+      print("""
+            local2
+            global2
+            """)
+      // CHECK-LABEL: barrier
+      print("""
+            barrier:
+            """)
+      // LOCAL: [[LOCAL]]3
+      // GLOBAL: [[$GLOBAL]]3
+      print("""
+            local3
+            global3
+            """)
+    }
+    XCTAssert(fileCheckOutput(of: .stdout, block: block))
+    XCTAssert(fileCheckOutput(of: .stdout, withPrefixes: ["CHECK", "GLOBAL"], block: block))
+    XCTAssert(fileCheckOutput(of: .stdout, withPrefixes: ["CHECK", "LOCAL"], block: block))
+    XCTAssert(fileCheckOutput(of: .stdout, withPrefixes: ["CHECK", "GLOBAL"], options: [.scopedVariables], block: block))
+    XCTAssertFalse(fileCheckOutput(of: .stdout, withPrefixes: ["CHECK", "LOCAL"], options: [.scopedVariables], block: block))
+  }
+  #if !os(macOS)
+  static var allTests = testCase([
+    ("testRegexScope", testRegexScope),
+  ])
+  #endif
+}
+

Tests/FileCheckTests/VariableRefSpec.swift

@@ -14,6 +14,7 @@ class VariableRefSpec : XCTestCase {
       print("op4 g1, g2, g1")
     })
   }
+  
   #if !os(macOS)
   static var allTests = testCase([
     ("testSameLineVarRef", testSameLineVarRef),

Tests/LinuxMain.swift

@@ -5,11 +5,13 @@ import XCTest
 #if !os(macOS)
 XCTMain([
   DAGSpec.allTests,
+  DefinesSpec.allTests,
   EmptySpec.allTests,
   FileCheckSpec.allTests,
   LabelSpec.allTests,
   LineCountSpec.allTests,
   MultiPrefixSpec.allTests,
+  RegexScopeSpec.allTests,
   VariableRefSpec.allTests,
 ])
 #endif