Merge pull request #191 from tfoleyNV/ir-work

More work on IR-based lowering and cross-compilation

1 files changed, 190 insertions, 0 deletions

diff --git a/source/slang/mangle.cpp b/source/slang/mangle.cpp
new file mode 100644
index 000000000..ce36a97b6
--- /dev/null
+++ b/source/slang/mangle.cpp
@@ -0,0 +1,190 @@
+#include "mangle.h"
+
+#include "name.h"
+#include "syntax.h"
+
+namespace Slang
+{
+    struct ManglingContext
+    {
+        StringBuilder sb;
+    };
+
+    void emitRaw(
+        ManglingContext*    context,
+        char const*         text)
+    {
+        context->sb.append(text);
+    }
+
+    void emit(
+        ManglingContext*    context,
+        UInt                value)
+    {
+        context->sb.append(value);
+    }
+
+    void emitName(
+        ManglingContext*    context,
+        Name*               name)
+    {
+        String str = getText(name);
+
+        // If the name consists of only traditional "identifer characters"
+        // (`[a-zA-Z_]`), then we wnat to emit it more or less directly.
+        //
+        // If it contains code points outside that range, we'll need to
+        // do something to encode them. I don't want to deal with
+        // that right now, so I'm going to ignore it.
+
+        // We prefix the string with its byte length, so that
+        // decoding doesn't have to worry about finding a terminator.
+        UInt length = str.Length();
+        emit(context, length);
+        context->sb.append(str);
+    }
+
+    void emitType(
+        ManglingContext*    context,
+        Type*               type)
+    {
+        // TODO: actually implement this bit...
+    }
+
+    void emitQualifiedName(
+        ManglingContext*    context,
+        Decl*               decl)
+    {
+        auto parentDecl = decl->ParentDecl;
+        if( parentDecl )
+        {
+            emitQualifiedName(context, parentDecl);
+        }
+
+        // A generic declaration is kind of a pseudo-declaration
+        // as far as the user is concerned; so we don't want
+        // to emit its name.
+        if( auto genericDecl = dynamic_cast<GenericDecl*>(decl) )
+        {
+            return;
+        }
+
+        emitName(context, decl->nameAndLoc.name);
+
+        if( auto parentGenericDecl = dynamic_cast<GenericDecl*>(parentDecl))
+        {
+            emitRaw(context, "g");
+            UInt genericParameterCount = 0;
+            for( auto mm : parentGenericDecl->Members )
+            {
+                if(mm.As<GenericTypeParamDecl>())
+                {
+                    genericParameterCount++;
+                }
+                else if(mm.As<GenericValueParamDecl>())
+                {
+                    genericParameterCount++;
+                }
+                else if(mm.As<GenericTypeConstraintDecl>())
+                {
+                    genericParameterCount++;
+                }
+                else
+                {
+                }
+            }
+
+            emit(context, genericParameterCount);
+            for( auto mm : parentGenericDecl->Members )
+            {
+                if(auto genericTypeParamDecl = mm.As<GenericTypeParamDecl>())
+                {
+                    emitRaw(context, "T");
+                }
+                else if(auto genericValueParamDecl = mm.As<GenericValueParamDecl>())
+                {
+                    emitRaw(context, "v");
+                    emitType(context, genericValueParamDecl->getType());
+                }
+                else if(mm.As<GenericTypeConstraintDecl>())
+                {
+                    emitRaw(context, "C");
+                    // TODO: actually emit info about the constraint
+                }
+                else
+                {
+                }
+            }
+        }
+
+        // If the declaration has parameters, then we need to emit
+        // those parameters to distinguish it from other declarations
+        // of the same name that might have different parameters.
+        //
+        // We'll also go ahead and emit the result type as well,
+        // just for completeness.
+        //
+        if( auto callableDecl = dynamic_cast<CallableDecl*>(decl) )
+        {
+            emitRaw(context, "p");
+            UInt parameterCount = callableDecl->GetParameters().Count();
+            emit(context, parameterCount);
+            for(auto pp : callableDecl->GetParameters())
+            {
+                emitType(context, pp->getType());
+            }
+
+            emitType(context, callableDecl->ReturnType);
+        }
+    }
+
+    void mangleName(
+        ManglingContext*    context,
+        Decl*               decl)
+    {
+        // TODO: catch cases where the declaration should
+        // forward to something else? E.g., what if we
+        // are asked to mangle the name of a `typedef`?
+
+        // We will start with a unique prefix to avoid
+        // clashes with user-defined symbols:
+        emitRaw(context, "_S");
+
+        // Next we will add a bit of info to register
+        // the *kind* of declaration we are dealing with.
+        //
+        // Functions will get no prefix, since we assume
+        // they are a common case:
+        if(dynamic_cast<FuncDecl*>(decl))
+        {}
+        // Types will get a `T` prefix:
+        else if(dynamic_cast<AggTypeDecl*>(decl))
+            emitRaw(context, "T");
+        else if(dynamic_cast<TypeDefDecl*>(decl))
+            emitRaw(context, "T");
+        // Variables will get a `V` prefix:
+        //
+        // TODO: probably need to pull constant-buffer
+        // declarations out of this...
+        else if(dynamic_cast<VarDeclBase*>(decl))
+            emitRaw(context, "V");
+        else
+        {
+            // TODO: handle other cases
+        }
+
+        // Now we encode the qualified name of the decl.
+        emitQualifiedName(context, decl);
+    }
+
+
+
+    String getMangledName(Decl* decl)
+    {
+        ManglingContext context;
+
+        mangleName(&context, decl);
+
+        return context.sb.ProduceString();
+    }
+}