From 5c1bc633075ec61cf660d35ac709969adb108d08 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Wed, 30 Nov 2016 23:19:05 +0000
Subject: [PATCH] llvm-lto2: Simpler workaround for PR30396.

Maintain the command line resolutions as a map to a list of resolutions
rather than a single resolution, and apply the resolutions in the order
observed. This is not only simpler but allows us to test the scenario where
the two symbols have different resolutions.

Differential Revision: https://reviews.llvm.org/D27285

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288288 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/ThinLTO/X86/module_asm_glob.ll |  1 +
 tools/llvm-lto2/llvm-lto2.cpp       | 27 ++++++++++-----------------
 2 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/test/ThinLTO/X86/module_asm_glob.ll b/test/ThinLTO/X86/module_asm_glob.ll
index 33588fa6e9a..bcc44c58c9f 100644
--- a/test/ThinLTO/X86/module_asm_glob.ll
+++ b/test/ThinLTO/X86/module_asm_glob.ll
@@ -6,6 +6,7 @@
 ; RUN: llvm-nm %t2.bc.thinlto.o | FileCheck  %s --check-prefix=NM1
 
 ; RUN: llvm-lto2 %t1.bc %t2.bc -o %t.o -save-temps \
+; RUN:     -r=%t1.bc,foo,lx \
 ; RUN:     -r=%t1.bc,foo,plx \
 ; RUN:     -r=%t1.bc,_simplefunction,pl \
 ; RUN:     -r=%t2.bc,main,plx \
diff --git a/tools/llvm-lto2/llvm-lto2.cpp b/tools/llvm-lto2/llvm-lto2.cpp
index b48f6c1993e..01756d2c764 100644
--- a/tools/llvm-lto2/llvm-lto2.cpp
+++ b/tools/llvm-lto2/llvm-lto2.cpp
@@ -109,7 +109,11 @@ int main(int argc, char **argv) {
 
   cl::ParseCommandLineOptions(argc, argv, "Resolution-based LTO test harness");
 
-  std::map<std::pair<std::string, std::string>, SymbolResolution>
+  // FIXME: Workaround PR30396 which means that a symbol can appear
+  // more than once if it is defined in module-level assembly and
+  // has a GV declaration. We allow (file, symbol) pairs to have multiple
+  // resolutions and apply them in the order observed.
+  std::map<std::pair<std::string, std::string>, std::list<SymbolResolution>>
       CommandLineResolutions;
   for (std::string R : SymbolResolutions) {
     StringRef Rest = R;
@@ -132,7 +136,7 @@ int main(int argc, char **argv) {
         llvm::errs() << "invalid character " << C << " in resolution: " << R
                      << '\n';
     }
-    CommandLineResolutions[{FileName, SymbolName}] = Res;
+    CommandLineResolutions[{FileName, SymbolName}].push_back(Res);
   }
 
   std::vector<std::unique_ptr<MemoryBuffer>> MBs;
@@ -166,12 +170,6 @@ int main(int argc, char **argv) {
         check(InputFile::create(MB->getMemBufferRef()), F);
 
     std::vector<SymbolResolution> Res;
-    // FIXME: Workaround PR30396 which means that a symbol can appear
-    // more than once if it is defined in module-level assembly and
-    // has a GV declaration. Keep track of the resolutions found in this
-    // file and remove them from the CommandLineResolutions map afterwards,
-    // so that we don't flag the second one as missing.
-    std::map<std::string, SymbolResolution> CurrentFileSymResolutions;
     for (const InputFile::Symbol &Sym : Input->symbols()) {
       auto I = CommandLineResolutions.find({F, Sym.getName()});
       if (I == CommandLineResolutions.end()) {
@@ -179,17 +177,12 @@ int main(int argc, char **argv) {
                      << ',' << Sym.getName() << '\n';
         HasErrors = true;
       } else {
-        Res.push_back(I->second);
-        CurrentFileSymResolutions[Sym.getName()] = I->second;
+        Res.push_back(I->second.front());
+        I->second.pop_front();
+        if (I->second.empty())
+          CommandLineResolutions.erase(I);
       }
     }
-    for (auto I : CurrentFileSymResolutions) {
-#ifndef NDEBUG
-      auto NumErased =
-#endif
-          CommandLineResolutions.erase({F, I.first});
-      assert(NumErased > 0);
-    }
 
     if (HasErrors)
       continue;
-- 
2.50.1