From 3f1fb88afb75613b9e600c6fbce1a628154044b6 Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Mon, 11 Dec 2017 21:52:21 +0000
Subject: [PATCH] [WebAssembly] Preserve ordering of global symbols

This change restores the behavior that global indexes
are assigned in object file order.  This was accidentally
changed in https://reviews.llvm.org/D40859.

Differential Revision: https://reviews.llvm.org/D41038

llvm-svn: 320426
---
 lld/test/wasm/data-layout.ll | 12 ++++++------
 lld/wasm/Writer.cpp          | 12 +++++-------
 2 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/lld/test/wasm/data-layout.ll b/lld/test/wasm/data-layout.ll
index dad8ea3466c3..1da4ff0710cb 100644
--- a/lld/test/wasm/data-layout.ll
+++ b/lld/test/wasm/data-layout.ll
@@ -20,11 +20,6 @@
 ; CHECK-NEXT:         Mutable:         false
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
-; CHECK-NEXT:           Value:           1052
-; CHECK-NEXT:       - Type:            I32
-; CHECK-NEXT:         Mutable:         false
-; CHECK-NEXT:         InitExpr:
-; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           1024
 ; CHECK-NEXT:       - Type:            I32
 ; CHECK-NEXT:         Mutable:         false
@@ -36,11 +31,16 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           1048
+; CHECK-NEXT:       - Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           1052
 
 ; CHECK:       - Type:            DATA
 ; CHECK-NEXT:     Relocations:
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_MEMORY_ADDR_I32
-; CHECK-NEXT:         Index:           1
+; CHECK-NEXT:         Index:           4
 ; CHECK-NEXT:         Offset:          0x0000001F
 ; CHECK-NEXT:     Segments:
 ; CHECK-NEXT:       - SectionOffset:   7
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
index bc7d969bb75e..7af5df3736cc 100644
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -614,15 +614,13 @@ void Writer::assignSymbolIndexes() {
   for (ObjFile *File : Symtab->ObjectFiles) {
     DEBUG(dbgs() << "assignSymbolIndexes: " << File->getName() << "\n");
     for (Symbol *Sym : File->getSymbols()) {
-      if (Sym->hasOutputIndex() || !Sym->isDefined())
+      // Assign indexes for symbols defined with this file.
+      if (!Sym->isDefined() || File != Sym->getFile())
         continue;
-
       if (Sym->isFunction()) {
-        if (Sym->getFile() && isa<ObjFile>(Sym->getFile())) {
-          auto *Obj = cast<ObjFile>(Sym->getFile());
-          Sym->setOutputIndex(Obj->FunctionIndexOffset +
-                              Sym->getFunctionIndex());
-        }
+        auto *Obj = cast<ObjFile>(Sym->getFile());
+        Sym->setOutputIndex(Obj->FunctionIndexOffset +
+                            Sym->getFunctionIndex());
       } else if (Config->EmitRelocs) {
         DefinedGlobals.emplace_back(Sym);
         Sym->setOutputIndex(GlobalIndex++);