Add support for pragma STDGL invariant(all)

Fixes #2689

glslang/MachineIndependent/ParseHelper.cpp

@@ -327,6 +327,16 @@ void TParseContext::setAtomicCounterBlockDefaults(TType& block) const
     block.getQualifier().layoutMatrix = ElmRowMajor;
 }
 
+void TParseContext::setInvariant(const TSourceLoc& loc, const char* builtin) {
+    TSymbol* symbol = symbolTable.find(builtin);
+    if (symbol && symbol->getType().getQualifier().isPipeOutput()) {
+        if (intermediate.inIoAccessed(builtin))
+            warn(loc, "changing qualification after use", "invariant", builtin);
+        TSymbol* csymbol = symbolTable.copyUp(symbol);
+        csymbol->getWritableType().getQualifier().invariant = true;
+    }
+}
+
 void TParseContext::handlePragma(const TSourceLoc& loc, const TVector<TString>& tokens)
 {
 #ifndef GLSLANG_WEB
@@ -404,8 +414,33 @@ void TParseContext::handlePragma(const TSourceLoc& loc, const TVector<TString>&
         intermediate.setUseVariablePointers();
     } else if (tokens[0].compare("once") == 0) {
         warn(loc, "not implemented", "#pragma once", "");
-    } else if (tokens[0].compare("glslang_binary_double_output") == 0)
+    } else if (tokens[0].compare("glslang_binary_double_output") == 0) {
         intermediate.setBinaryDoubleOutput();
+    } else if (spvVersion.spv > 0 && tokens[0].compare("STDGL") == 0 &&
+               tokens[1].compare("invariant") == 0 && tokens[3].compare("all") == 0) {
+        intermediate.setInvariantAll();
+        // Set all builtin out variables invariant if declared
+        setInvariant(loc, "gl_Position");
+        setInvariant(loc, "gl_PointSize");
+        setInvariant(loc, "gl_ClipDistance");
+        setInvariant(loc, "gl_CullDistance");
+        setInvariant(loc, "gl_TessLevelOuter");
+        setInvariant(loc, "gl_TessLevelInner");
+        setInvariant(loc, "gl_PrimitiveID");
+        setInvariant(loc, "gl_Layer");
+        setInvariant(loc, "gl_ViewportIndex");
+        setInvariant(loc, "gl_FragDepth");
+        setInvariant(loc, "gl_SampleMask");
+        setInvariant(loc, "gl_ClipVertex");
+        setInvariant(loc, "gl_FrontColor");
+        setInvariant(loc, "gl_BackColor");
+        setInvariant(loc, "gl_FrontSecondaryColor");
+        setInvariant(loc, "gl_BackSecondaryColor");
+        setInvariant(loc, "gl_TexCoord");
+        setInvariant(loc, "gl_FogFragCoord");
+        setInvariant(loc, "gl_FragColor");
+        setInvariant(loc, "gl_FragData");
+    }
 #endif
 }
 
@@ -3651,6 +3686,8 @@ void TParseContext::globalQualifierFixCheck(const TSourceLoc& loc, TQualifier& q
         profileRequires(loc, ENoProfile, 130, nullptr, "out for stage outputs");
         profileRequires(loc, EEsProfile, 300, nullptr, "out for stage outputs");
         qualifier.storage = EvqVaryingOut;
+        if (intermediate.isInvariantAll())
+            qualifier.invariant = true;
         break;
     case EvqInOut:
         qualifier.storage = EvqVaryingIn;

glslang/MachineIndependent/ParseHelper.h

@@ -241,6 +241,7 @@ protected:
     // override this to set the language-specific name
     virtual const char* getAtomicCounterBlockName() const { return ""; }
     virtual void setAtomicCounterBlockDefaults(TType&) const {}
+    virtual void setInvariant(const TSourceLoc& loc, const char* builtin) {}
     virtual void finalizeAtomicCounterBlockLayout(TVariable&) {}
     bool isAtomicCounterBlock(const TSymbol& symbol) {
         const TVariable* var = symbol.getAsVariable();
@@ -511,6 +512,7 @@ protected:
     virtual const char* getAtomicCounterBlockName() const override;
     virtual void finalizeAtomicCounterBlockLayout(TVariable&) override;
     virtual void setAtomicCounterBlockDefaults(TType& block) const override;
+    virtual void setInvariant(const TSourceLoc& loc, const char* builtin) override;
 
 public:
     //

glslang/MachineIndependent/linkValidate.cpp

@@ -316,6 +316,7 @@ void TIntermediate::mergeModes(TInfoSink& infoSink, TIntermediate& unit)
     MERGE_TRUE(useUnknownFormat);
     MERGE_TRUE(hlslOffsets);
     MERGE_TRUE(useStorageBuffer);
+    MERGE_TRUE(invariantAll);
     MERGE_TRUE(hlslIoMapping);
 
     // TODO: sourceFile

glslang/MachineIndependent/localintermediate.h

@@ -291,6 +291,7 @@ public:
         numEntryPoints(0), numErrors(0), numPushConstants(0), recursive(false),
         invertY(false),
         useStorageBuffer(false),
+        invariantAll(false),
         nanMinMaxClamp(false),
         depthReplacing(false),
         uniqueId(0),
@@ -560,6 +561,8 @@ public:
 
     void setUseStorageBuffer() { useStorageBuffer = true; }
     bool usingStorageBuffer() const { return useStorageBuffer; }
+    void setInvariantAll() { invariantAll = true; }
+    bool isInvariantAll() const { return invariantAll; }
     void setDepthReplacing() { depthReplacing = true; }
     bool isDepthReplacing() const { return depthReplacing; }
     bool setLocalSize(int dim, int size)
@@ -1063,6 +1066,7 @@ protected:
     bool recursive;
     bool invertY;
     bool useStorageBuffer;
+    bool invariantAll;
     bool nanMinMaxClamp;            // true if desiring min/max/clamp to favor non-NaN over NaN
     bool depthReplacing;
     int localSize[3];