feat: optimize evaluator control flow and data handling for scalars by Nelson-numerical-software · Pull Request #1545 · nelson-lang/nelson

Nelson-numerical-software · 2026-03-03T20:32:48Z

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Pull request overview

This PR optimizes scalar handling and evaluator control flow by introducing inline (small-buffer) storage for scalar payloads and reducing redundant work in hot paths.

Changes:

Added inline storage (small buffer optimization) for scalar Data/ArrayOf to avoid heap allocations.
Refactored type resolution and control-flow evaluation to reduce copies and unnecessary branching.
Reduced some evaluator overhead (breakpoint checks, cleanup invocations, recursion updates).

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
modules/types/src/include/Data.hpp	Adds inline-buffer fields and a new scalar-data constructor for `Data`.
modules/types/src/include/ArrayOf.hpp	Adds a new scalar inline-data constructor for `ArrayOf`.
modules/types/src/cpp/FindCommonType.cpp	Refactors relational common-type resolution to reduce copies/calls and streamline branching.
modules/types/src/cpp/Data.cpp	Implements inline scalar storage in `Data` and updates cleanup behavior for inline vs heap data.
modules/types/src/cpp/ArrayOf_SingleType.cpp	Switches scalar constructors to inline-data `ArrayOf` constructor.
modules/types/src/cpp/ArrayOf_MissingType.cpp	Switches missing scalar constructor to inline-data `ArrayOf` constructor.
modules/types/src/cpp/ArrayOf_LogicalType.cpp	Switches logical scalar constructor to inline-data `ArrayOf` constructor.
modules/types/src/cpp/ArrayOf_IntegersType.cpp	Switches integer scalar construction to inline-data path; tweaks nullptr constructor calls.
modules/types/src/cpp/ArrayOf_HandleType.cpp	Switches handle scalar construction to inline-data path.
modules/types/src/cpp/ArrayOf_DoubleType.cpp	Switches double/dcomplex scalar construction to inline-data path.
modules/types/src/cpp/ArrayOf_Constructors.cpp	Adjusts empty constructors to disambiguate/null pointer arguments.
modules/types/src/cpp/ArrayOf.cpp	Implements the new inline scalar `ArrayOf` constructor.
modules/interpreter/src/cpp/MacroFunctionDef.cpp	Avoids redundant local-function insertion and skips lock/update during recursion; avoids unnecessary cleanup calls.
modules/interpreter/src/cpp/EvaluatorDebug.cpp	Adds fast-path return for no breakpoints; reduces copies.
modules/interpreter/src/cpp/EvaluatorControlFlow.cpp	Refactors `if` handling to reduce branching and early-return when condition is true.

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Copilot · 2026-03-03T20:38:44Z

modules/types/src/cpp/Data.cpp

+    : owners(1), dimensions(dims), dataClass(aClass), sparse(false), isInline(true)
+{
+    std::memcpy(inlineBuffer, scalarData, dataSize);
+    cp = inlineBuffer;


dataSize is copied into inlineBuffer without checking against INLINE_BUFFER_SIZE, which can overflow the buffer and cause memory corruption. Add a size check (e.g., if dataSize > INLINE_BUFFER_SIZE then fall back to heap allocation / existing allocation path, or enforce/validate scalar sizes before calling this constructor).

Suggested change

: owners(1), dimensions(dims), dataClass(aClass), sparse(false), isInline(true)

{

std::memcpy(inlineBuffer, scalarData, dataSize);

cp = inlineBuffer;

: owners(1), dimensions(dims), dataClass(aClass), sparse(false), isInline(false)

{

if (dataSize <= INLINE_BUFFER_SIZE) {

std::memcpy(inlineBuffer, scalarData, dataSize);

cp = inlineBuffer;

isInline = true;

} else {

void* heapData = ::operator new(dataSize);

std::memcpy(heapData, scalarData, dataSize);

cp = heapData;

// isInline remains false for heap-allocated storage

}

Copilot · 2026-03-03T20:38:45Z

modules/interpreter/src/cpp/EvaluatorDebug.cpp

+        const std::wstring& sbFile = sb.filename;
        if (!sbFile.empty() && filenamesMatch(sbFile, context->getCurrentScope()->getFilename())) {
-            std::string currentFunction = context->getCurrentScope()->getName();
+            const std::string& currentFunction = context->getCurrentScope()->getName();


Binding a const std::string& to the result of getName() is only safe if getName() returns a reference; if it returns by value, this becomes a dangling reference. Store by value (as before) or use auto currentFunction = ...; unless getName() is guaranteed to return const std::string&.

Suggested change

const std::string& currentFunction = context->getCurrentScope()->getName();

const std::string& currentFunction = currentFunctionName;

Copilot · 2026-03-03T20:38:45Z

modules/interpreter/src/cpp/MacroFunctionDef.cpp

-    updateCode();
-    if (isScript) {
-        return evaluateMScript(eval, inputs, nargout);
+    // Skip lock/updateCode on recursive calls � code cannot change mid-recursion.


The comment contains an invalid/garbled character ('�'), likely from an encoding issue. Replace it with a standard dash or punctuation to avoid mojibake in source files.

Suggested change

// Skip lock/updateCode on recursive calls � code cannot change mid-recursion.

// Skip lock/updateCode on recursive calls - code cannot change mid-recursion.

Copilot · 2026-03-03T20:38:46Z

modules/types/src/cpp/FindCommonType.cpp

+    // Check double and single types (use bitwise OR for efficiency)
+    bool isDoubleType = (Aclass == NLS_DOUBLE || Aclass == NLS_DCOMPLEX || Bclass == NLS_DOUBLE
+        || Bclass == NLS_DCOMPLEX);
+    bool isSingleType = (Aclass == NLS_SINGLE || Aclass == NLS_SCOMPLEX || Bclass == NLS_SINGLE
+        || Bclass == NLS_SCOMPLEX);


The comment says "use bitwise OR" but the code uses logical OR (||). Update the comment to match the implementation (or change the implementation if you truly intended bitwise ops), otherwise it’s misleading for future maintainers.

Copilot · 2026-03-03T20:38:46Z

modules/types/src/cpp/ArrayOf_Constructors.cpp

 {
    if (dim.getElementCount() == 0) {
-        return ArrayOf(NLS_CELL_ARRAY, dim, nullptr, false);
+        return ArrayOf(NLS_CELL_ARRAY, dim, (void*)nullptr, false);


Using C-style casts like (void*)nullptr is discouraged in C++ because it can hide unsafe conversions. Prefer passing nullptr directly (if overload resolution is unambiguous) or use static_cast<void*>(nullptr) for clarity.

Copilot · 2026-03-03T20:38:46Z

modules/types/src/cpp/ArrayOf_Constructors.cpp

 {
    if (dim.getElementCount() == 0) {
-        return ArrayOf(NLS_DOUBLE, dim, nullptr, bIsSparse);
+        return ArrayOf(NLS_DOUBLE, dim, (void*)nullptr, bIsSparse);


Using C-style casts like (void*)nullptr is discouraged in C++ because it can hide unsafe conversions. Prefer passing nullptr directly (if overload resolution is unambiguous) or use static_cast<void*>(nullptr) for clarity.

Copilot · 2026-03-03T20:38:46Z

modules/types/src/cpp/ArrayOf_Constructors.cpp

    if (((m == 0) && (n == 0)) || ((m == 0) && (n != 0)) || ((m != 0) && (n == 0))) {
        Dimensions dim(m, n);
-        return ArrayOf(NLS_DOUBLE, dim, nullptr, bIsSparse);
+        return ArrayOf(NLS_DOUBLE, dim, (void*)nullptr, bIsSparse);


Using C-style casts like (void*)nullptr is discouraged in C++ because it can hide unsafe conversions. Prefer passing nullptr directly (if overload resolution is unambiguous) or use static_cast<void*>(nullptr) for clarity.

feat: optimize evaluator control flow and data handling for scalars

2d4ad3e

Nelson-numerical-software requested a review from Copilot March 3, 2026 20:32

Copilot AI reviewed Mar 3, 2026

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Copilot started reviewing on behalf of Nelson-numerical-software March 3, 2026 21:07 View session

Nelson-numerical-software merged commit 6ea08d0 into master Mar 4, 2026
45 of 47 checks passed

Nelson-numerical-software deleted the small-speed-optimization branch March 4, 2026 09:43

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feat: optimize evaluator control flow and data handling for scalars#1545

feat: optimize evaluator control flow and data handling for scalars#1545
Nelson-numerical-software merged 1 commit intomasterfrom
small-speed-optimization

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-    : owners(1), dimensions(dims), dataClass(aClass), sparse(false), isInline(true)
-{
-    std::memcpy(inlineBuffer, scalarData, dataSize);
-    cp = inlineBuffer;
+    : owners(1), dimensions(dims), dataClass(aClass), sparse(false), isInline(false)
+{
+    if (dataSize <= INLINE_BUFFER_SIZE) {
+        std::memcpy(inlineBuffer, scalarData, dataSize);
+        cp = inlineBuffer;
+        isInline = true;
+    } else {
+        void* heapData = ::operator new(dataSize);
+        std::memcpy(heapData, scalarData, dataSize);
+        cp = heapData;
+        // isInline remains false for heap-allocated storage
+    }

	const std::string& currentFunction = context->getCurrentScope()->getName();
	const std::string& currentFunction = currentFunctionName;

	// Skip lock/updateCode on recursive calls � code cannot change mid-recursion.
	// Skip lock/updateCode on recursive calls - code cannot change mid-recursion.

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