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feat: Add option to discard variable information when compiling classes
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@Col-E
Col-E committed Jan 17, 2025
1 parent 79d8354 commit 0783630
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Showing 2 changed files with 81 additions and 71 deletions.
10 changes: 10 additions & 0 deletions jasm-composition-jvm/src/main/java/me/darknet/assembler/compile/JvmCompilerOptions.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ public class JvmCompilerOptions implements CompilerOptions<JvmCompilerOptions> {
protected String annotationPath;
protected InheritanceChecker inheritanceChecker = ReflectiveInheritanceChecker.INSTANCE;
protected JvmAnalysisEngineFactory engineProvider = TypedJvmAnalysisEngine::new;
private boolean doWriteVariables = true;

public JvmCompilerOptions() {
this.asmArgs = ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS;
Expand Down Expand Up @@ -100,4 +101,13 @@ public JvmCompilerOptions inheritanceChecker(InheritanceChecker checker) {
this.inheritanceChecker = checker;
return this;
}

public boolean doWriteVariables() {
return doWriteVariables;
}

public JvmCompilerOptions doWriteVariables(boolean doWriteVariables) {
this.doWriteVariables = doWriteVariables;
return this;
}
}
142 changes: 71 additions & 71 deletions jasm-composition-jvm/src/main/java/me/darknet/assembler/compile/visitor/BlwCodeVisitor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ public class BlwCodeVisitor implements ASTJvmInstructionVisitor, JavaOpcodes {
private final VarCache varCache = new VarCache();
private final List<ASTInstruction> visitedInstructions = new ArrayList<>();
private final JvmAnalysisEngine<Frame> analysisEngine;
private final boolean writeVariables;
private ASTInstruction currentInstructionAst;
private int opcode = 0;

Expand All @@ -60,6 +61,7 @@ public BlwCodeVisitor(JvmCompilerOptions options, ErrorCollector errorCollector,
this.errorCollector = errorCollector;
this.analysisEngine = (JvmAnalysisEngine<Frame>) options.createEngine(varCache);
this.parameters = parameters;
this.writeVariables = options.doWriteVariables();

analysisEngine.setErrorCollector(errorCollector);

Expand Down Expand Up @@ -236,12 +238,11 @@ public void visitLookupSwitchInsn(ASTObject lookupSwitchObject) {
keys.add(Integer.parseInt(pair.first().content()));
labels.add(getOrCreateLabel(pair.second().content()));
}
add(
new LookupSwitchInstruction(
keys.stream().mapToInt(Integer::intValue).toArray(), getOrCreateLabel(defaultLabel.content()),
labels
)
);
add(new LookupSwitchInstruction(
keys.stream().mapToInt(Integer::intValue).toArray(),
getOrCreateLabel(defaultLabel.content()),
labels
));
}

@Override
Expand Down Expand Up @@ -286,25 +287,22 @@ public void visitMethodInsn(ASTIdentifier path, ASTIdentifier descriptor) {

@Override
public void visitInvokeDynamicInsn(ASTIdentifier name, ASTIdentifier descriptor, ASTElement bsm, ASTArray bsmArgs) {

Handle handle;

if(bsm instanceof ASTIdentifier identifier) {
if (bsm instanceof ASTIdentifier identifier) {
handle = Handle.HANDLE_SHORTCUTS.get(identifier.content());
} else if(bsm instanceof ASTArray array) {
} else if (bsm instanceof ASTArray array) {
handle = Handle.from(array);
} else {
throw new IllegalStateException("Unexpected value: " + bsm);
}

add(
new InvokeDynamicInstruction(
name.literal(),
Objects.requireNonNullElse(new TypeReader(descriptor.literal()).read(), Types.OBJECT),
ConstantMapper.methodHandleFromHandle(handle),
bsmArgs.values().stream().filter(Objects::nonNull).map(ConstantMapper::fromConstant).toList()
)
);
add(new InvokeDynamicInstruction(
name.literal(),
Objects.requireNonNullElse(new TypeReader(descriptor.literal()).read(), Types.OBJECT),
ConstantMapper.methodHandleFromHandle(handle),
bsmArgs.values().stream().filter(Objects::nonNull).map(ConstantMapper::fromConstant).toList()
));
}

@Override
Expand Down Expand Up @@ -363,7 +361,8 @@ public void visitEnd() {
int index = parameter.index();
String name = parameter.name();
ClassType type = parameter.safeType();
codeBuilder.localVariable(new GenericLocal(begin, end, index, name, type, null));
if (writeVariables)
codeBuilder.localVariable(new GenericLocal(begin, end, index, name, type, null));

// Mark parameter variable as being assigned before the code
var parameterVar = varCache.getFirstByIndex(index);
Expand Down Expand Up @@ -392,61 +391,62 @@ public void visitEnd() {
errorCollector.addError(ex.getMessage(), Location.UNKNOWN);
}

// Populate variables
// - Our variables are not scoped, so we can merge by name.
// - Known 'null' locals can merge with duplicate locals which may have type info associated with them
Map<String, Local> localsMap = new HashMap<>();
int paramOffset = parameters.size();
analysisEngine.frames().forEach((index, frame) -> {
for (Local local : frame.locals().toList()) {
// Skip parameters
if (local.index() < paramOffset)
continue;

localsMap.merge(local.name(), local, (a, b) -> {
ClassType at = a.type(); // These may be 'null' for known 'null' values
ClassType bt = b.type();

// Edge cases: If we have null values use the other local (with type info hopefully)
if (at == null)
return b;
if (bt == null)
return a;

// Edge case: If the types aren't of the same sort they cannot possibly be merged.
// There is no "correct" solution at this step, so just yield object and call it a day.
//
// Reproduction code:
// ldc "foo"
// astore foo
// bipush 10
// istore foo <--- Foo cannot be an object and an int in our system
if (at.getClass() != bt.getClass())
return a.adaptType(Types.OBJECT);

// Merge locals by type
try {
return a.adaptType(common(at, bt));
} catch (ValueMergeException e) {
// If the values could not be merged, report where the failure originated from.
CodeElement element = code.elements().get(index);
ASTInstruction ast = analysisEngine.getCodeToAstMap().get(element);
if (ast != null) {
errorCollector.addError(e.getMessage(), ast.location());
if (writeVariables) {
// Populate variables
// - Our variables are not scoped, so we can merge by name.
// - Known 'null' locals can merge with duplicate locals which may have type info associated with them
Map<String, Local> localsMap = new HashMap<>();
int paramOffset = parameters.size();
analysisEngine.frames().forEach((index, frame) -> {
for (Local local : frame.locals().toList()) {
// Skip parameters
if (local.index() < paramOffset)
continue;

localsMap.merge(local.name(), local, (a, b) -> {
ClassType at = a.type(); // These may be 'null' for known 'null' values
ClassType bt = b.type();

// Edge cases: If we have null values use the other local (with type info hopefully)
if (at == null)
return b;
if (bt == null)
return a;

// Edge case: If the types aren't of the same sort they cannot possibly be merged.
// There is no "correct" solution at this step, so just yield object and call it a day.
//
// Reproduction code:
// ldc "foo"
// astore foo
// bipush 10
// istore foo <--- Foo cannot be an object and an int in our system
if (at.getClass() != bt.getClass())
return a.adaptType(Types.OBJECT);
} else {
throw new IllegalStateException();
}
}
});
}
});

localsMap.forEach((name, local) -> {
int index = local.index();
ClassType type = local.safeType();
codeBuilder.localVariable(new GenericLocal(begin, end, index, name, type, null));
});
// Merge locals by type
try {
return a.adaptType(common(at, bt));
} catch (ValueMergeException e) {
// If the values could not be merged, report where the failure originated from.
CodeElement element = code.elements().get(index);
ASTInstruction ast = analysisEngine.getCodeToAstMap().get(element);
if (ast != null) {
errorCollector.addError(e.getMessage(), ast.location());
return a.adaptType(Types.OBJECT);
} else {
throw new IllegalStateException();
}
}
});
}
});
localsMap.forEach((name, local) -> {
int index = local.index();
ClassType type = local.safeType();
codeBuilder.localVariable(new GenericLocal(begin, end, index, name, type, null));
});
}
}

private void add(@NotNull Instruction instruction) {
Expand Down

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