commit 6d40bbdd9c61a654c707445ccddc0cb7e620d737
author Olli Etuaho <oetuaho@nvidia.com> Fri Sep 30 13:49:38 2016 +0100
committer Commit Bot <commit-bot@chromium.org> Mon Oct 10 09:19:32 2016 +0000
tree 2bcc00a4aa340c09296919b5d5e68225774982be
parent d0694d988138242d741aeff8a3669158cc0ab5c2

Split TIntermBlock from TIntermAggregate

The new TIntermBlock node class replaces TIntermAggregate nodes with
the EOpSequence op. It represents the root node of the tree which is
a list of declarations and function definitions, and any code blocks
that can be denoted by curly braces. These include function and loop
bodies, and if-else branches.

This change enables a bunch of more compile-time type checking, and
makes the AST code easier to understand and less error-prone.

The PostProcess step that used to be done to ensure that the root node
is TIntermAggregate is removed in favor of making sure that the root
node is a TIntermBlock in the glslang.y parsing code.

Intermediate output formatting is improved to print the EOpNull error
in a clearer way.

After this patch, TIntermAggregate is still used for function
definitions, function prototypes, function parameter lists, function
calls, variable and invariant declarations and the comma (sequence)
operator.

BUG=angleproject:1490
TEST=angle_unittests, angle_end2end_tests

Change-Id: I04044affff979a11577bc1fe75d747e538b799c8
Reviewed-on: https://chromium-review.googlesource.com/393726
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/compiler/translator/RewriteElseBlocks.cpp

diff --git a/src/compiler/translator/RewriteElseBlocks.cpp b/src/compiler/translator/RewriteElseBlocks.cpp
index 13d71c7..c9427e2 100644
--- a/src/compiler/translator/RewriteElseBlocks.cpp
+++ b/src/compiler/translator/RewriteElseBlocks.cpp
@@ -26,6 +26,7 @@
 
   protected:
     bool visitAggregate(Visit visit, TIntermAggregate *aggregate) override;
+    bool visitBlock(Visit visit, TIntermBlock *block) override;
 
   private:
     const TType *mFunctionType;
@@ -40,31 +41,29 @@
 
 bool ElseBlockRewriter::visitAggregate(Visit visit, TIntermAggregate *node)
 {
-    switch (node->getOp())
+    if (node->getOp() == EOpFunction)
     {
-      case EOpSequence:
-        if (visit == PostVisit)
+        // Store the current function context (see comment below)
+        mFunctionType = ((visit == PreVisit) ? &node->getType() : nullptr);
+    }
+    return true;
+}
+
+bool ElseBlockRewriter::visitBlock(Visit visit, TIntermBlock *node)
+{
+    if (visit == PostVisit)
+    {
+        for (size_t statementIndex = 0; statementIndex != node->getSequence()->size();
+             statementIndex++)
         {
-            for (size_t statementIndex = 0; statementIndex != node->getSequence()->size(); statementIndex++)
+            TIntermNode *statement = (*node->getSequence())[statementIndex];
+            TIntermIfElse *ifElse  = statement->getAsIfElseNode();
+            if (ifElse && ifElse->getFalseBlock() != nullptr)
             {
-                TIntermNode *statement = (*node->getSequence())[statementIndex];
-                TIntermIfElse *ifElse  = statement->getAsIfElseNode();
-                if (ifElse && ifElse->getFalseBlock() != nullptr)
-                {
-                    (*node->getSequence())[statementIndex] = rewriteIfElse(ifElse);
-                }
+                (*node->getSequence())[statementIndex] = rewriteIfElse(ifElse);
             }
         }
-        break;
-
-      case EOpFunction:
-        // Store the current function context (see comment below)
-        mFunctionType = ((visit == PreVisit) ? &node->getType() : NULL);
-        break;
-
-      default: break;
     }
-
     return true;
 }
 
@@ -77,13 +76,13 @@
     TIntermTyped *typedCondition     = ifElse->getCondition()->getAsTyped();
     TIntermAggregate *storeCondition = createTempInitDeclaration(typedCondition);
 
-    TIntermAggregate *falseBlock = nullptr;
+    TIntermBlock *falseBlock = nullptr;
 
     TType boolType(EbtBool, EbpUndefined, EvqTemporary);
 
     if (ifElse->getFalseBlock())
     {
-        TIntermAggregate *negatedElse = nullptr;
+        TIntermBlock *negatedElse = nullptr;
         // crbug.com/346463
         // D3D generates error messages claiming a function has no return value, when rewriting
         // an if-else clause that returns something non-void in a function. By appending dummy
@@ -94,7 +93,7 @@
                 mFunctionType->getBasicString();
             TString rawText = "return (" + typeString + ")0";
             TIntermRaw *returnNode = new TIntermRaw(*mFunctionType, rawText);
-            negatedElse = new TIntermAggregate(EOpSequence);
+            negatedElse            = new TIntermBlock();
             negatedElse->getSequence()->push_back(returnNode);
         }
 
@@ -102,14 +101,14 @@
         TIntermUnary *negatedCondition     = new TIntermUnary(EOpLogicalNot, conditionSymbolElse);
         TIntermIfElse *falseIfElse =
             new TIntermIfElse(negatedCondition, ifElse->getFalseBlock(), negatedElse);
-        falseBlock = TIntermediate::EnsureSequence(falseIfElse);
+        falseBlock = TIntermediate::EnsureBlock(falseIfElse);
     }
 
     TIntermSymbol *conditionSymbolSel = createTempSymbol(boolType);
     TIntermIfElse *newIfElse =
         new TIntermIfElse(conditionSymbolSel, ifElse->getTrueBlock(), falseBlock);
 
-    TIntermAggregate *block = new TIntermAggregate(EOpSequence);
+    TIntermBlock *block = new TIntermBlock();
     block->getSequence()->push_back(storeCondition);
     block->getSequence()->push_back(newIfElse);