Harden barebone checks and enforce explicit atomics for volatile fields

[shai-almog]

Motivation

• Prevent incorrect "barebone" method classification when methods use local slots beyond argument slots or modify locals via IINC which wasn't accounted for.
• Avoid silently allowing opcodes that can implicitly throw (divide/remainder) in methods considered barebone.
• Ensure volatile field code generation uses explicit atomic initialization and explicit acquire/release memory ordering to avoid undefined ordering and initialization issues.

Description

• Added getVar() to IInc so the local index used by IINC is visible to analysis (vm/.../bytecodes/IInc.java).
• Tightened BytecodeMethod.checkBarebone() to scan instructions for maximum local index used by VarOp and IInc and reject barebone if that index is >= argument slots (vm/.../BytecodeMethod.java).
• Removed implicit divide/remainder opcodes from the allowed barebone instruction set to avoid methods that could throw implicitly from being marked barebone (vm/.../BytecodeMethod.java).
• Modified volatile field codegen to use ATOMIC_VAR_INIT(0) for static volatile initialization and to call atomic_load_explicit(..., memory_order_acquire) / atomic_store_explicit(..., memory_order_release) for static and instance volatile accesses, including GC mark paths and static field marking (vm/.../ByteCodeClass.java).

Testing

• No automated tests were executed as part of this change.

---

Codex Task

[github-actions]

✅ ByteCodeTranslator Quality Report

Test & Coverage

• ✅ Tests: 171 total, 0 failed, 2 skipped

Benchmark Results

• Execution Time: 9690 ms

• Hotspots (Top 20 sampled methods):

  • 22.78% java.lang.String.indexOf (384 samples)
  • 18.03% com.codename1.tools.translator.Parser.isMethodUsed (304 samples)
  • 16.37% com.codename1.tools.translator.Parser.addToConstantPool (276 samples)
  • 6.41% java.util.ArrayList.indexOf (108 samples)
  • 4.98% java.lang.Object.hashCode (84 samples)
  • 3.44% com.codename1.tools.translator.ByteCodeClass.calcUsedByNative (58 samples)
  • 2.91% com.codename1.tools.translator.BytecodeMethod.optimize (49 samples)
  • 2.85% java.lang.System.identityHashCode (48 samples)
  • 2.31% com.codename1.tools.translator.ByteCodeClass.fillVirtualMethodTable (39 samples)
  • 1.25% com.codename1.tools.translator.Parser.cullMethods (21 samples)
  • 1.01% com.codename1.tools.translator.Parser.generateClassAndMethodIndexHeader (17 samples)
  • 0.95% com.codename1.tools.translator.BytecodeMethod.equals (16 samples)
  • 0.83% java.io.FileOutputStream.writeBytes (14 samples)
  • 0.83% java.lang.StringBuilder.append (14 samples)
  • 0.65% java.io.UnixFileSystem.getBooleanAttributes0 (11 samples)
  • 0.65% com.codename1.tools.translator.BytecodeMethod.isMethodUsedByNative (11 samples)
  • 0.59% java.util.TreeMap.getEntry (10 samples)
  • 0.59% java.util.ArrayList$Itr.hasNext (10 samples)
  • 0.53% java.io.FileOutputStream.open0 (9 samples)
  • 0.53% com.codename1.tools.translator.Parser.getClassByName (9 samples)

• ⚠️ Coverage report not generated.

Static Analysis

• ✅ SpotBugs: no findings (report was not generated by the build).
• ⚠️ PMD report not generated.
• ⚠️ Checkstyle report not generated.

Generated automatically by the PR CI workflow.

[github-actions]

✅ Continuous Quality Report

Test & Coverage

• ✅ Tests: 2282 total, 0 failed, 0 skipped
• 📊 Line coverage: 52.80% [HTML preview] [Download]
  • Lowest covered classes
    • com.codename1.io.rest.RequestBuilder$FetchAsPropertyListActionListener – 0.00%
    • com.codename1.io.rest.RequestBuilder$FetchAsPropertiesActionListener – 0.00%
    • com.codename1.ui.Display$EdtException – 0.00%
    • com.codename1.ui.BrowserWindow$BrowserForm – 0.00%
    • com.codename1.ui.plaf.CSSBorder$LinearGradient – 0.00%
    • com.codename1.io.rest.RequestBuilder$GetAsStringAsyncImplActionListener – 0.00%
    • com.codename1.io.rest.RequestBuilder$GetAsJsonMapActionListener – 0.00%
    • com.codename1.payment.Purchase$SynchronizeReceiptsSyncRunnable – 0.00%
    • com.codename1.io.rest.RequestBuilder$GetAsBytesAsyncImplActionListener – 0.00%
    • com.codename1.io.rest.RequestBuilder$FetchAsJsonMapActionListener – 0.00%

Static Analysis

• ✅ SpotBugs: 0 findings (no issues) [Report archive]
• ❌ PMD: 6177 findings (P2: 42, P3: 5833, P4: 302) [HTML preview] [Download]
  • Top findings
    • P2: CodenameOne/src/com/codename1/capture/Capture.java:250 – Use of modifier volatile is not recommended. (rule: AvoidUsingVolatile)
    • P2: CodenameOne/src/com/codename1/compat/java/util/Objects.java:47 – The method name and parameter number are suspiciously close to equals(Object) (rule: SuspiciousEqualsMethodName)
    • P2: CodenameOne/src/com/codename1/components/StorageImageAsync.java:42 – Use of modifier volatile is not recommended. (rule: AvoidUsingVolatile)
    • P2: CodenameOne/src/com/codename1/components/StorageImageAsync.java:44 – Use of modifier volatile is not recommended. (rule: AvoidUsingVolatile)
    • P2: CodenameOne/src/com/codename1/io/BufferedInputStream.java:38 – Use of modifier volatile is not recommended. (rule: AvoidUsingVolatile)
    • …and 6172 more
• ❌ Checkstyle: 220771 findings (Warning: 220771) [HTML preview] [Download]
  • Top findings
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:30:1 – Extra separation in import group before 'java.io.IOException' (rule: CustomImportOrderCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:32 – First sentence of Javadoc is missing an ending period. (rule: SummaryJavadocCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:36 – Line is longer than 100 characters (found 143). (rule: LineLengthCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:39:5 – 'member def modifier' has incorrect indentation level 4, expected level should be 2. (rule: IndentationCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:40:5 – 'member def modifier' has incorrect indentation level 4, expected level should be 2. (rule: IndentationCheck)
    • …and 220766 more

Generated automatically by the PR CI workflow.

[shai-almog]

iOS screenshot updates

Compared 30 screenshots: 23 matched, 6 updated, 1 missing reference.

• BrowserComponent — updated screenshot. Screenshot differs (1206x2622 px, bit depth 8).

  
  Preview info: Preview provided by instrumentation.
  Full-resolution PNG saved as BrowserComponent.png in workflow artifacts.

• graphics-draw-arc — updated screenshot. Screenshot differs (1206x2622 px, bit depth 8).

  
  Preview info: JPEG preview quality 20; JPEG preview quality 20; downscaled to 603x1311.
  Full-resolution PNG saved as graphics-draw-arc.png in workflow artifacts.

• graphics-draw-gradient — updated screenshot. Screenshot differs (1206x2622 px, bit depth 8).

  
  Preview info: JPEG preview quality 10; JPEG preview quality 10; downscaled to 844x1835.
  Full-resolution PNG saved as graphics-draw-gradient.png in workflow artifacts.

• graphics-draw-round-rect — missing reference. Reference screenshot missing at /Users/runner/work/CodenameOne/CodenameOne/scripts/ios/screenshots/graphics-draw-round-rect.png.

  
  Preview info: JPEG preview quality 10; JPEG preview quality 10; downscaled to 844x1835.
  Full-resolution PNG saved as graphics-draw-round-rect.png in workflow artifacts.

• graphics-draw-string — updated screenshot. Screenshot differs (1206x2622 px, bit depth 8).

  
  Preview info: JPEG preview quality 10; JPEG preview quality 10; downscaled to 422x918.
  Full-resolution PNG saved as graphics-draw-string.png in workflow artifacts.

• graphics-draw-string-decorated — updated screenshot. Screenshot differs (1206x2622 px, bit depth 8).

  
  Preview info: JPEG preview quality 10; JPEG preview quality 10; downscaled to 603x1311.
  Full-resolution PNG saved as graphics-draw-string-decorated.png in workflow artifacts.

• kotlin — updated screenshot. Screenshot differs (1206x2622 px, bit depth 8).

  
  Preview info: Preview provided by instrumentation.
  Full-resolution PNG saved as kotlin.png in workflow artifacts.

Benchmark Results

• VM Translation Time: 412 seconds
• Compilation Time: 150 seconds

Detailed Performance Metrics

Metric	Duration
Build Time Statistics
Setup & Unzip	40824 ms
Extract Extensions	21 ms
Google Services Setup	2 ms
Scan Classes	665 ms
Extract Libs	1201 ms
Inject Build Hints	777 ms
Generate Unit Tests	13 ms
Generate Stubs	1636 ms
Compile Stubs	2917 ms
Generate Icons	1318 ms
Prepare ParparVM	288 ms
ParparVM Execution	238276 ms
Post-VM Setup	164 ms
CocoaPods	7985 ms
Finalize	62 ms
Total Time	296151 msMaven Overhead : 116000 ms
CocoaPods Install (Script)	1000 ms
Simulator Boot (Run)	87000 ms
App Install	17000 ms
App Launch	18000 ms
Test Execution	186000 ms