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Add FloatingLiteral.ValueAsFloat and ValueAsDouble. #675

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rolfbjarne wants to merge 1 commit into from
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Add FloatingLiteral.ValueAsFloat and ValueAsDouble. #675

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26 changes: 26 additions & 0 deletions sources/ClangSharp.Interop/Extensions/CXCursor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -917,6 +917,32 @@ public readonly CXCursor DefaultArg

public readonly double FloatingLiteralValueAsApproximateDouble => clangsharp.Cursor_getFloatingLiteralValueAsApproximateDouble(this);

public readonly double? FloatingLiteralValueAsDouble
{
get
{
double value = default;
if (clangsharp.Cursor_getFloatingLiteralValueAsDouble(this, &value) != 0)
{
return value;
}
return null;
}
}

public readonly float? FloatingLiteralValueAsFloat
{
get
{
float value = default;
if (clangsharp.Cursor_getFloatingLiteralValueAsFloat(this, &value) != 0)
{
return value;
}
return null;
}
}

public readonly int FieldDeclBitWidth => clang.getFieldDeclBitWidth(this);

public readonly int FieldIndex => clangsharp.Cursor_getFieldIndex(this);
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10 changes: 9 additions & 1 deletion sources/ClangSharp.Interop/clangsharp/clangsharp.cs
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Expand Up @@ -6,7 +6,7 @@

namespace ClangSharp.Interop;

public static partial class @clangsharp
public static unsafe partial class @clangsharp
{
[DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getArgument", ExactSpelling = true)]
public static extern CXCursor Cursor_getArgument(CXCursor C, [NativeTypeName("unsigned int")] uint i);
Expand Down Expand Up @@ -240,6 +240,14 @@ public static partial class @clangsharp
[DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getFloatingLiteralValueAsApproximateDouble", ExactSpelling = true)]
public static extern double Cursor_getFloatingLiteralValueAsApproximateDouble(CXCursor C);

[DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getFloatingLiteralValueAsDouble", ExactSpelling = true)]
[return: NativeTypeName("unsigned int")]
public static extern uint Cursor_getFloatingLiteralValueAsDouble(CXCursor C, double* value);

[DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getFloatingLiteralValueAsFloat", ExactSpelling = true)]
[return: NativeTypeName("unsigned int")]
public static extern uint Cursor_getFloatingLiteralValueAsFloat(CXCursor C, float* value);

[DllImport("libClangSharp", CallingConvention = CallingConvention.Cdecl, EntryPoint = "clangsharp_Cursor_getFoundDecl", ExactSpelling = true)]
public static extern CXCursor Cursor_getFoundDecl(CXCursor C);

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4 changes: 4 additions & 0 deletions sources/ClangSharp/Cursors/Exprs/FloatingLiteral.cs
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Expand Up @@ -39,5 +39,9 @@ internal FloatingLiteral(CXCursor handle) : base(handle, CXCursor_FloatingLitera

public double ValueAsApproximateDouble => Handle.FloatingLiteralValueAsApproximateDouble;

public double? ValueAsDouble => Handle.FloatingLiteralValueAsDouble;

public float? ValueAsFloat => Handle.FloatingLiteralValueAsFloat;

public string ValueString => _valueString.Value;
}
32 changes: 32 additions & 0 deletions sources/libClangSharp/ClangSharp.cpp
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Expand Up @@ -1367,6 +1367,38 @@ double clangsharp_Cursor_getFloatingLiteralValueAsApproximateDouble(CXCursor C)
return 0;
}

unsigned clangsharp_Cursor_getFloatingLiteralValueAsDouble(CXCursor C, double* value) {
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@tannergooding tannergooding Jan 6, 2026

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Not sure I understand the need for these APIs?

ValueAsApproximateDouble only loses data in the case that we have some "more precise" type than double, such as x87DoubleExtended or IEEEquad (which aren't portable to C# right now anyways).

So what it looks like you want is just some unsigned clangsharp_Cursor_isFloatingLiteralRepresentableBy(CXCursor C, CX_FloatingSemantics semantics).

Such an API then allows this to be more generally supported in managed land instead, as you can simply check "is the floating-literal regardless of semantics losslessly representable by this other semantic". You can then take and cast ValueAsApproximateDouble to the target format in that case for the two types that are being supported here.

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@rolfbjarne rolfbjarne Jan 7, 2026

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OK, I'll try ValueAsApproximateDouble and see if that works.

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@rolfbjarne rolfbjarne Jan 8, 2026

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ValueAsApproximateDouble works fine, so this is not needed, thanks!

if (isStmtOrExpr(C.kind)) {
const Stmt* S = getCursorStmt(C);

if (const FloatingLiteral* FL = dyn_cast<FloatingLiteral>(S)) {
llvm::APFloat fl = FL->getValue();
if (fl.isRepresentableBy(fl.getSemantics(), fl.IEEEdouble())) {
*value = FL->getValue ().convertToDouble();
return 1;
}
}
}

return 0;
}

unsigned clangsharp_Cursor_getFloatingLiteralValueAsFloat(CXCursor C, float* value) {
if (isStmtOrExpr(C.kind)) {
const Stmt* S = getCursorStmt(C);

if (const FloatingLiteral* FL = dyn_cast<FloatingLiteral>(S)) {
llvm::APFloat fl = FL->getValue();
if (fl.isRepresentableBy(fl.getSemantics(), fl.IEEEsingle())) {
*value = FL->getValue ().convertToFloat();
return 1;
}
}
}

return 0;
}

CXCursor clangsharp_Cursor_getFoundDecl(CXCursor C) {
if (isStmtOrExpr(C.kind)) {
const Stmt* S = getCursorStmt(C);
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4 changes: 4 additions & 0 deletions sources/libClangSharp/ClangSharp.h
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Expand Up @@ -379,6 +379,10 @@ CLANGSHARP_LINKAGE CX_FloatingSemantics clangsharp_Cursor_getFloatingLiteralSema

CLANGSHARP_LINKAGE double clangsharp_Cursor_getFloatingLiteralValueAsApproximateDouble(CXCursor C);

CLANGSHARP_LINKAGE unsigned clangsharp_Cursor_getFloatingLiteralValueAsDouble(CXCursor C, double* value);

CLANGSHARP_LINKAGE unsigned clangsharp_Cursor_getFloatingLiteralValueAsFloat(CXCursor C, float* value);

CLANGSHARP_LINKAGE CXCursor clangsharp_Cursor_getFoundDecl(CXCursor C);

CLANGSHARP_LINKAGE CXCursor clangsharp_Cursor_getField(CXCursor C, unsigned i);
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41 changes: 41 additions & 0 deletions tests/ClangSharp.UnitTests/CursorTests/DeclTest.cs
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Expand Up @@ -97,6 +97,47 @@ class tuple;
Assert.That(packElements[1].AsType.AsString, Is.EqualTo("long"));
}

[Test]
public void FloatingLiteral()
{
ObjectiveCTest.AssertNeedNewClangSharp();

var inputContents = $$"""
const float F1 = 3.14f;
const double D1 = 2.718281828;
const long double Q1 = 1.61803398874989484820458683436563811772030917980576286213544862270526046281890244L;
""";

using var translationUnit = CreateTranslationUnit(inputContents);

var decls = translationUnit.TranslationUnitDecl.Decls.OfType<VarDecl>().ToList();

var checkConstant = (string constantName, float? expectedFloat, double? expectedDouble, double expectedApproximateDouble) => {
var constant = decls.SingleOrDefault(e => e.Name == constantName)!;
var expr = constant.Init!;
if (expr is ImplicitCastExpr castExpr)
{
expr = castExpr.SubExpr;
}
if (expr is FloatingLiteral floatingLiteral)
{
Assert.That(floatingLiteral.ValueAsFloat, Is.EqualTo(expectedFloat).Within(0.0001), $"Constant {constantName} float value mismatch");
Assert.That(floatingLiteral.ValueAsDouble, Is.EqualTo(expectedDouble).Within(0.0001), $"Constant {constantName} double value mismatch");
Assert.That(floatingLiteral.ValueAsApproximateDouble, Is.EqualTo(expectedApproximateDouble).Within(0.0001), $"Constant {constantName} double value mismatch");
}
else
{
Assert.Fail($"Constant {constantName} InitExpr is not FloatingLiteral, but {expr.GetType().Name}");
}
};

Assert.Multiple(() => {
checkConstant("F1", 3.14f, 3.14, 3.14);
checkConstant("D1", null, 2.718281828, 2.718281828);
checkConstant("Q1", null, 1.61803398874989484820458683436563811772030917980576, 1.61803398874989484820458683436563811772030917980576);
});
}

[Test]
public void IsPodTest()
{
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