Sanitize debug source location tracking for implicit branch and return

This patch tries to attach debug location of a branch/return instruction to its predecessor or the closing brace. If none could be found, no debug info should be emitted.

glslang/Include/intermediate.h

@@ -1694,8 +1694,12 @@ typedef TVector<TStorageQualifier> TQualifierList;
 //
 class TIntermAggregate : public TIntermOperator {
 public:
-    TIntermAggregate() : TIntermOperator(EOpNull), userDefined(false), pragmaTable(nullptr) { }
-    TIntermAggregate(TOperator o) : TIntermOperator(o), pragmaTable(nullptr) { }
+    TIntermAggregate() : TIntermOperator(EOpNull), userDefined(false), pragmaTable(nullptr) { 
+        endLoc.init();
+    }
+    TIntermAggregate(TOperator o) : TIntermOperator(o), pragmaTable(nullptr) {
+        endLoc.init();
+    }
     ~TIntermAggregate() { delete pragmaTable; }
     virtual       TIntermAggregate* getAsAggregate()       { return this; }
     virtual const TIntermAggregate* getAsAggregate() const { return this; }
@@ -1719,6 +1723,9 @@ public:
     void setSpirvInstruction(const TSpirvInstruction& inst) { spirvInst = inst; }
     const TSpirvInstruction& getSpirvInstruction() const { return spirvInst; }
 
+    void setEndLoc(TSourceLoc loc) { endLoc = loc; }
+    TSourceLoc getEndLoc() const { return endLoc; }
+
     void setLinkType(TLinkType l) { linkType = l; }
     TLinkType getLinkType() const { return linkType; }
 protected:
@@ -1733,6 +1740,10 @@ protected:
     TPragmaTable* pragmaTable;
     TSpirvInstruction spirvInst;
     TLinkType linkType = ELinkNone;
+
+    // Marking the end source location of the aggregate.
+    // This is currently only set for a compound statement or a function body, pointing to '}'.
+    TSourceLoc endLoc;
 };
 
 //

glslang/MachineIndependent/glslang.y

@@ -3773,8 +3773,10 @@ compound_statement
         --parseContext.statementNestingLevel;
     }
       RIGHT_BRACE {
-        if ($3 && $3->getAsAggregate())
+        if ($3 && $3->getAsAggregate()) {
             $3->getAsAggregate()->setOperator(parseContext.intermediate.getDebugInfo() ? EOpScope : EOpSequence);
+            $3->getAsAggregate()->setEndLoc($5.loc);
+        }
         $$ = $3;
     }
     ;
@@ -3810,8 +3812,10 @@ compound_statement_no_new_scope
         $$ = 0;
     }
     | LEFT_BRACE statement_list RIGHT_BRACE {
-        if ($2 && $2->getAsAggregate())
+        if ($2 && $2->getAsAggregate()) {
             $2->getAsAggregate()->setOperator(EOpSequence);
+            $2->getAsAggregate()->setEndLoc($3.loc);
+        }
         $$ = $2;
     }
     ;