Simplify CapabilitySet Diagnostic Printing (shader-slang#4678)

Fixes: shader-slang#4675
Fixes: shader-slang#4683
Fixes: shader-slang#4443
Fixes: shader-slang#4585
Fixes: shader-slang#4172

Made the following changes:
1. All capability diagnostic printing logic tries to simplify before printing. This means that we do not print atoms which imply another atom.
2. Do not print the `_` prefix part of atom names since it is misleading users on what they should use to solve a capability issue encountered. (`_Internal` `External` atom changes are not in this PR)
3. Bundle together printing of all sets which contain exactly the same atoms (excluding abstract atoms). This allows printing the following `vertex/fragment/hull/domain/... + glsl` instead of `vertex + glsl | fragment + glsl | hull + glsl | domain + glsl | ....`
4. Rework how entry-point errors are reported to users (example at bottom of PR comment)
5. Rework how atom-provenance data is collected to be leaner and more useful so we can rework the errors. There are 2 notable changes here:
    * We no longer store a list which describes where the first of an `CapabilityAtom` comes from. This heavily simplifies AST logic for the capability system. AST parsing of capabilities is much faster. The trade-off is faster AST parsing and correct AST node data for slower diagnostics if an error is found
    * atom-provenance data now stores a reference to an atom's use-site to provide information on **where** and **what** is wrong with user code versus only sharing **what** and not where.

source/slang/slang-ast-base.h

@@ -743,7 +743,7 @@ class Decl : public DeclBase
     bool isChildOf(Decl* other) const;
 
     // Track the decl reference that caused the requirement of a capability atom.
-    SLANG_UNREFLECTED Dictionary<CapabilityAtom, DeclReferenceWithLoc> capabilityRequirementProvenance;
+    SLANG_UNREFLECTED List<DeclReferenceWithLoc> capabilityRequirementProvenance;
 private:
     SLANG_UNREFLECTED DeclRefBase* m_defaultDeclRef = nullptr;
     SLANG_UNREFLECTED Index m_defaultDeclRefEpoch = -1;

source/slang/slang-capability.cpp

@@ -165,6 +165,57 @@ bool isCapabilityDerivedFrom(CapabilityAtom atom, CapabilityAtom base)
     return false;
 }
 
+//CapabilityAtomSet
+
+CapabilityAtomSet CapabilityAtomSet::newSetWithoutImpliedAtoms() const
+{
+    // plan is to add all atoms which is impled (=>) another atom.
+    // Implying an atom appears in the form of atom1=>atom2 or atom2=>atom1.
+    Dictionary<CapabilityAtom, bool> candidateForSimplifiedList;
+    CapabilityAtomSet simplifiedSet;
+    for (auto atom1UInt : *this)
+    {
+        CapabilityAtom atom1 = (CapabilityAtom)atom1UInt;
+        if (!candidateForSimplifiedList.addIfNotExists(atom1, true)
+            && candidateForSimplifiedList[atom1] == false)
+            continue;
+
+        for (auto atom2UInt : *this)
+        {
+            if (atom1UInt == atom2UInt)
+                continue;
+
+            CapabilityAtom atom2 = (CapabilityAtom)atom2UInt;
+            if (!candidateForSimplifiedList.addIfNotExists(atom2, true)
+                && candidateForSimplifiedList[atom2] == false)
+                continue;
+
+            auto atomInfo1 = _getInfo(atom1).canonicalRepresentation;
+            auto atomInfo2 = _getInfo(atom2).canonicalRepresentation;
+            for (auto atomSet1 : atomInfo1)
+            {
+                for (auto atomSet2 : atomInfo2)
+                {
+                    if (atomSet1->contains(*atomSet2))
+                    {
+                        candidateForSimplifiedList[atom2] = false;
+                        continue;
+                    }
+                    else if (atomSet2->contains(*atomSet1))
+                    {
+                        candidateForSimplifiedList[atom1] = false;
+                        continue;
+                    }
+                }
+            }
+        }
+    }
+    for (auto i : candidateForSimplifiedList)
+        if(i.second)
+            simplifiedSet.add((UInt)i.first);
+    return simplifiedSet;
+}
+
 //// CapabiltySet
 
 CapabilityAtom getTargetAtomInSet(const CapabilityAtomSet& atomSet)
@@ -897,31 +948,118 @@ void CapabilitySet::addSpirvVersionFromOtherAsGlslSpirvVersion(CapabilitySet& ot
     }
 }
 
-void printDiagnosticArg(StringBuilder& sb, const CapabilitySet& capSet)
+UnownedStringSlice capabilityNameToStringWithoutPrefix(CapabilityName capabilityName)
+{
+    auto name = capabilityNameToString(capabilityName);
+    if (name.startsWith("_"))
+        return name.tail(1);
+    return name;
+}
+
+void printDiagnosticArg(StringBuilder& sb, const CapabilityAtomSet atomSet)
+{
+    bool isFirst = true;
+    for (auto atom : atomSet.newSetWithoutImpliedAtoms())
+    {
+        CapabilityName formattedAtom = (CapabilityName)atom;
+        if (!isFirst)
+            sb << " + ";
+        sb << capabilityNameToStringWithoutPrefix(formattedAtom);
+        isFirst = false;
+    }
+}
+
+// Collection of stages which have same atom sets to compress reprisentation of atom and stage per target
+struct CompressedCapabilitySet
 {
-    bool isFirstSet = true;
-    for (auto& set : capSet.getAtomSets())
+    /// Collection of stages which have same atom sets to compress reprisentation of atom and stage: {vertex/fragment, ... } 
+    struct StageAndAtomSet
+    {
+        CapabilityAtomSet stages;
+        CapabilityAtomSet atomsWithoutStage;
+    };
+
+    auto begin()
     {
-        if (!isFirstSet)
+        return atomSetsOfTargets.begin();
+    }
+
+    /// Compress 1 capabilitySet into a reprisentation which merges stages that share all of their atoms for printing.
+    Dictionary<CapabilityAtom, List<StageAndAtomSet>> atomSetsOfTargets;
+    CompressedCapabilitySet(const CapabilitySet& capabilitySet)
+    {
+        for (auto& atomSet : capabilitySet.getAtomSets())
         {
-            sb<< " | ";
+            auto target = getTargetAtomInSet(atomSet);
+
+            auto stageInSetAtom = getStageAtomInSet(atomSet);
+            CapabilityAtomSet stageInSet;
+            stageInSet.add((UInt)stageInSetAtom);
+
+            CapabilityAtomSet atomsWithoutStage;
+            CapabilityAtomSet::calcSubtract(atomsWithoutStage, atomSet, stageInSet);
+            if (!atomSetsOfTargets.containsKey(target))
+            {
+                atomSetsOfTargets[target].add({ stageInSet, atomsWithoutStage });
+                continue;
+            }
+
+            // try to find an equivlent atom set by iterating all of the same `atomSetsOfTarget[target]` and merge these 2 together.
+            auto& atomSetsOfTarget = atomSetsOfTargets[target];
+            for (auto& i : atomSetsOfTarget)
+            {
+                if (i.atomsWithoutStage.contains(atomsWithoutStage) && atomsWithoutStage.contains(i.atomsWithoutStage))
+                {
+                    i.stages.add((UInt)stageInSetAtom);
+                }
+            }
         }
-        bool isFirst = true;
-        for (auto atom : set)
+        for (auto& targetSets : atomSetsOfTargets)
+            for (auto& targetSet : targetSets.second)
+                targetSet.atomsWithoutStage = targetSet.atomsWithoutStage.newSetWithoutImpliedAtoms();
+    }
+};
+
+void printDiagnosticArg(StringBuilder& sb, const CompressedCapabilitySet& capabilitySet)
+{
+ ////Secondly we will print our new list of atomSet's.
+    sb << "{";
+    bool firstSet = true;
+    for (auto targetSets : capabilitySet.atomSetsOfTargets)
+    {
+        if(!firstSet)
+            sb << " || ";
+        for (auto targetSet : targetSets.second)
         {
-            CapabilityName formattedAtom = (CapabilityName)atom;
-            if (!isFirst)
+            bool firstStage = true;
+            for (auto stageAtom : targetSet.stages)
+            {
+                if (!firstStage)
+                    sb << "/";
+                printDiagnosticArg(sb, (CapabilityName)stageAtom);
+                firstStage = false;
+            }
+            for (auto atom : targetSet.atomsWithoutStage)
             {
                 sb << " + ";
+                printDiagnosticArg(sb, (CapabilityName)atom);
             }
-            auto name = capabilityNameToString((CapabilityName)formattedAtom);
-            if (name.startsWith("_"))
-                name = name.tail(1);
-            sb << name;
-            isFirst = false;
         }
-        isFirstSet = false;
+        firstSet = false;
     }
+    sb << "}";
+}
+
+void printDiagnosticArg(StringBuilder& sb, const CapabilitySet& capabilitySet)
+{
+    // Firstly we will compress the printing of capabilities such that any atomSet
+    // with different abstract atoms but equal non-abstract atoms will be bundled together.
+    if (capabilitySet.isInvalid() || capabilitySet.isEmpty())
+    {
+        sb << "{}";
+        return;
+    }
+    printDiagnosticArg(sb, CompressedCapabilitySet(capabilitySet));
 }
 
 void printDiagnosticArg(StringBuilder& sb, CapabilityAtom atom)
@@ -931,20 +1069,15 @@ void printDiagnosticArg(StringBuilder& sb, CapabilityAtom atom)
 
 void printDiagnosticArg(StringBuilder& sb, CapabilityName name)
 {
-    sb << _getInfo(name).name;
+    sb << capabilityNameToStringWithoutPrefix(name);
 }
 
 void printDiagnosticArg(StringBuilder& sb, List<CapabilityAtom>& list)
 {
-    sb << "{";
-    auto count = list.getCount();
-    for(Index i = 0; i < count; i++)
-    {
-        printDiagnosticArg(sb, list[i]);
-        if (i + 1 != count)
-            sb << ", ";
-    }
-    sb << "}";
+    CapabilityAtomSet set;
+    for (auto i : list)
+        set.add((UInt)i);
+    printDiagnosticArg(sb, set.newSetWithoutImpliedAtoms());
 }
 
 

source/slang/slang-capability.h

@@ -51,6 +51,8 @@ namespace Slang
 struct CapabilityAtomSet : UIntSet
 {
     using UIntSet::UIntSet;
+
+    CapabilityAtomSet newSetWithoutImpliedAtoms() const;
 };
 
 struct CapabilityTargetSet;
@@ -300,6 +302,22 @@ struct CapabilitySet
     /// Add spirv version capabilities from 'spirv CapabilityTargetSet' as glsl_spirv version capability in 'glsl CapabilityTargetSet'
     void addSpirvVersionFromOtherAsGlslSpirvVersion(CapabilitySet& other);
 
+    /// Gets the first valid compile-target found in the CapabilitySet
+    CapabilityAtom getCompileTarget()
+    {
+        if(isEmpty() || isInvalid())
+            return CapabilityAtom::Invalid;
+        return (*m_targetSets.begin()).first;
+    }
+
+    /// Gets the first valid stage found in the CapabilitySet
+    CapabilityAtom getTargetStage()
+    {
+        if(isEmpty() || isInvalid())
+            return CapabilityAtom::Invalid;
+        return (*(*m_targetSets.begin()).second.shaderStageSets.begin()).first;
+    }
+
 private:
     /// underlying data of CapabilitySet.
     CapabilityTargetSets m_targetSets{};