[go] cmd/compile: tweak rewriting to leave original exported declarations

[David Chase (Gerrit)]

David Chase has uploaded the change for review

Commit message

cmd/compile: tweak rewriting to leave original exported declarations

While testing unsafe.Sizeof, discovered problems with exported
functions and variables.  Leaving the originals behind puts them
in the export data and allows the pre-rewrite parse to work correctly.

Change-Id: Icd53978ab0f448c2fdb126bcd4decd0403f564cc

Change diff

diff --git a/src/cmd/compile/internal/midway/analysis.go b/src/cmd/compile/internal/midway/analysis.go
index d977957..45c8ded 100644
--- a/src/cmd/compile/internal/midway/analysis.go
+++ b/src/cmd/compile/internal/midway/analysis.go
@@ -74,11 +74,9 @@
 		return false
 	}
 	// Walk the body and check identifiers
+	// This will also note any variable references that are dependent.
 	found := false
 	syntax.Inspect(fn.Body, func(n syntax.Node) bool {
-		if found {
-			return false
-		}
 		if id, ok := n.(*syntax.Name); ok {
 			obj := a.info.Uses[id]
 			if obj == nil {
@@ -98,6 +96,10 @@
 					}
 				}
 				if a.isDependentType(obj.Type()) {
+					if obj, ok := obj.(*types2.Var); ok && !a.dependentObj[obj] {
+						// For some reason, variable references need this special treatment
+						a.dependentObj[obj] = true
+					}
 					found = true
 					return false
 				}
diff --git a/src/cmd/compile/internal/midway/rewrite.go b/src/cmd/compile/internal/midway/rewrite.go
index 34269e6..022b036 100644
--- a/src/cmd/compile/internal/midway/rewrite.go
+++ b/src/cmd/compile/internal/midway/rewrite.go
@@ -93,7 +93,12 @@
 			}
 
 			if r.analyzer.HasDependentSignature(sig) {
-				// Drop dependent signatures entirely
+				if o := r.info.Defs[d.Name]; o != nil && !o.Exported() {
+					// Drop unexported dependent signatures entirely
+					continue
+				}
+				d.Body = r.blockOf(d.Pos(), r.panicStmt(d.Pos(), "Unexpected call of original function rewritten to specialized SIMD"))
+				newDecls = append(newDecls, d)
 				continue
 			}
 
@@ -110,7 +115,7 @@
 					break // Keep entire var decl if any name is clean, else drop
 				}
 			}
-			if keep {
+			if keep || true {
 				newDecls = append(newDecls, d)
 			}
 		case *syntax.TypeDecl:
@@ -285,20 +290,33 @@
 		switchStmt.Body = append(switchStmt.Body, caseClause)
 	}
 
-	fnName := "panic"
-	fnIdent := pe(syntax.NewName(d.Pos(), fnName))
+	panicStmt := r.panicStmt(d.Pos(), "unsupported vector size in simd-rewritten code")
+	return r.blockOf(d.Pos(), switchStmt, panicStmt)
+}
 
+func (r *Rewriter) blockOf(p syntax.Pos, stmts ...syntax.Stmt) *syntax.BlockStmt {
+	for _, s := range stmts {
+		s.SetPos(p)
+	}
+	blockStmt := &syntax.BlockStmt{List: stmts}
+	blockStmt.SetPos(p)
+	return blockStmt
+}
+
+func (r *Rewriter) panicStmt(p syntax.Pos, unquotedMessage string) *syntax.ExprStmt {
+	pe := func(e syntax.Expr) syntax.Expr {
+		e.SetPos(p)
+		return e
+	}
+	fnName := "panic"
+	fnIdent := pe(syntax.NewName(p, fnName))
 	callExpr := pe(&syntax.CallExpr{
 		Fun:     fnIdent,
-		ArgList: []syntax.Expr{pe(&syntax.BasicLit{Value: "\"unsupported vector size in simd-rewritten code\"", Kind: syntax.StringLit})},
+		ArgList: []syntax.Expr{pe(&syntax.BasicLit{Value: `"` + unquotedMessage + `"`, Kind: syntax.StringLit})},
 	})
-
 	panicStmt := &syntax.ExprStmt{X: callExpr}
-	blockStmt := &syntax.BlockStmt{List: []syntax.Stmt{ps(switchStmt), ps(panicStmt)}}
-
-	blockStmt.SetPos(d.Pos())
-
-	return blockStmt
+	panicStmt.SetPos(p)
+	return panicStmt
 }
 
 func (r *Rewriter) generateForSize(fileAST *syntax.File, k int, newDecls []syntax.Decl) []syntax.Decl {

Change information

Files:

• M src/cmd/compile/internal/midway/analysis.go
• M src/cmd/compile/internal/midway/rewrite.go

Change size: S

Delta: 2 files changed, 34 insertions(+), 14 deletions(-)

Open in Gerrit

Related details

Attention set is empty

Submit Requirements:

• Code-Review
• No-Unresolved-Comments
• Review-Enforcement
• TryBots-Pass

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

Gerrit-MessageType: newchange

Gerrit-Project: go

Gerrit-Branch: master

Gerrit-Change-Id: Icd53978ab0f448c2fdb126bcd4decd0403f564cc

Gerrit-Change-Number: 788960

Gerrit-PatchSet: 1

Gerrit-Owner: David Chase <drc...@google.com>

Gerrit-Reviewer: David Chase <drc...@google.com>