commit 010ce6a15a180cb8f9cd634f1bcf5f7ae2c09c42
author Brian Osman <brianosman@google.com> Mon Oct 19 16:34:10 2020 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Mon Oct 26 15:25:03 2020 +0000
tree 39c03dd4b7c7c8e602b75c145ce202233cd1e550
parent 0a7e2fa5d51eff98763803a8c25f32be71d88a52

Add ProgramUsage side-car to track variable and function references

Automatically computed once IR generation is complete, and then used
throughout optimization and inlining, and the backend generators.
Optimization and inlining are reworked to keep the data up-to-date as
they edit the IR.

Bug: skia:10589
Change-Id: Iaded42d8157732dd6fe05f74c5b7bb8366916635
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/328382
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

src/sksl/SkSLInliner.cpp

diff --git a/src/sksl/SkSLInliner.cpp b/src/sksl/SkSLInliner.cpp
index f29ab93..3b013b6 100644
--- a/src/sksl/SkSLInliner.cpp
+++ b/src/sksl/SkSLInliner.cpp
@@ -1141,36 +1141,13 @@
     }
 }
 
-static bool multiple_calls_to(const Program& program, const FunctionDeclaration* fn) {
-    class MultipleCallVisitor : public ProgramVisitor {
-    public:
-        MultipleCallVisitor(const FunctionDeclaration* function) : fFunction(function) {}
-
-        bool visitExpression(const Expression& e) override {
-            if (e.is<FunctionCall>() && &e.as<FunctionCall>().function() == fFunction) {
-                if (fCalled) {
-                    return true;
-                }
-                fCalled = true;
-            }
-            return INHERITED::visitExpression(e);
-        }
-
-        const FunctionDeclaration* fFunction;
-        bool fCalled = false;
-        using INHERITED = ProgramVisitor;
-    };
-
-    MultipleCallVisitor visitor(fn);
-    return visitor.visit(program);
-}
-
 bool Inliner::analyze(Program& program) {
     // A threshold of zero indicates that the inliner is completely disabled, so we can just return.
     if (fSettings->fInlineThreshold <= 0) {
         return false;
     }
 
+    ProgramUsage* usage = program.fUsage.get();
     InlineCandidateList candidateList;
     this->buildCandidateList(program, &candidateList);
 
@@ -1179,13 +1156,12 @@
     bool madeChanges = false;
     for (const InlineCandidate& candidate : candidateList.fCandidates) {
         FunctionCall& funcCall = (*candidate.fCandidateExpr)->as<FunctionCall>();
-        const FunctionDeclaration* funcDecl = &funcCall.function();
+        const FunctionDeclaration& funcDecl = funcCall.function();
 
         // If the function is large, not marked `inline`, and is called more than once, it's a bad
         // idea to inline it.
         if (candidate.fIsLargeFunction &&
-            !(funcDecl->modifiers().fFlags & Modifiers::kInline_Flag) &&
-            multiple_calls_to(program, funcDecl)) {
+            !(funcDecl.modifiers().fFlags & Modifiers::kInline_Flag) && usage->get(funcDecl) > 1) {
             continue;
         }
 
@@ -1203,6 +1179,9 @@
             // Ensure that the inlined body has a scope if it needs one.
             this->ensureScopedBlocks(inlinedCall.fInlinedBody.get(), candidate.fParentStmt->get());
 
+            // Add references within the inlined body
+            usage->add(inlinedCall.fInlinedBody.get());
+
             // Move the enclosing statement to the end of the unscoped Block containing the inlined
             // function, then replace the enclosing statement with that Block.
             // Before:
@@ -1216,6 +1195,7 @@
         }
 
         // Replace the candidate function call with our replacement expression.
+        usage->replace(candidate.fCandidateExpr->get(), inlinedCall.fReplacementExpr.get());
         *candidate.fCandidateExpr = std::move(inlinedCall.fReplacementExpr);
         madeChanges = true;