[llvm] r254054 - AsmParser: Make the code for parsing unnamed aliases more closely resemble that for unnamed globals.

[Peter Collingbourne via llvm-commits]

Author: pcc
Date: Tue Nov 24 20:54:07 2015
New Revision: 254054

URL: http://llvm.org/viewvc/llvm-project?rev=254054&view=rev
Log:
AsmParser: Make the code for parsing unnamed aliases more closely resemble that for unnamed globals.

This fixes parsing of forward references to unnamed aliases.

While here, remove an unnecessary isa check.

Modified:
    llvm/trunk/lib/AsmParser/LLParser.cpp
    llvm/trunk/test/Assembler/alias-redefinition.ll
    llvm/trunk/test/Assembler/unnamed-alias.ll

Modified: llvm/trunk/lib/AsmParser/LLParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLParser.cpp?rev=254054&r1=254053&r2=254054&view=diff
==============================================================================
--- llvm/trunk/lib/AsmParser/LLParser.cpp (original)
+++ llvm/trunk/lib/AsmParser/LLParser.cpp Tue Nov 24 20:54:07 2015
@@ -713,6 +713,24 @@ bool LLParser::ParseAlias(const std::str
         ExplicitTypeLoc,
         "explicit pointee type doesn't match operand's pointee type");
 
+  GlobalValue *GVal = nullptr;
+
+  // See if the alias was forward referenced, if so, prepare to replace the
+  // forward reference.
+  if (!Name.empty()) {
+    GVal = M->getNamedValue(Name);
+    if (GVal) {
+      if (!ForwardRefVals.erase(Name))
+        return Error(NameLoc, "redefinition of global '@" + Name + "'");
+    }
+  } else {
+    auto I = ForwardRefValIDs.find(NumberedVals.size());
+    if (I != ForwardRefValIDs.end()) {
+      GVal = I->second.first;
+      ForwardRefValIDs.erase(I);
+    }
+  }
+
   // Okay, create the alias but do not insert it into the module yet.
   std::unique_ptr<GlobalAlias> GA(
       GlobalAlias::create(Ty, AddrSpace, (GlobalValue::LinkageTypes)Linkage,
@@ -725,26 +743,17 @@ bool LLParser::ParseAlias(const std::str
   if (Name.empty())
     NumberedVals.push_back(GA.get());
 
-  // See if this value already exists in the symbol table.  If so, it is either
-  // a redefinition or a definition of a forward reference.
-  if (GlobalValue *Val = M->getNamedValue(Name)) {
-    // See if this was a redefinition.  If so, there is no entry in
-    // ForwardRefVals.
-    auto I = ForwardRefVals.find(Name);
-    if (I == ForwardRefVals.end())
-      return Error(NameLoc, "redefinition of global named '@" + Name + "'");
-
-    // Otherwise, this was a definition of forward ref.  Verify that types
-    // agree.
-    if (Val->getType() != GA->getType())
-      return Error(NameLoc,
-              "forward reference and definition of alias have different types");
+  if (GVal) {
+    // Verify that types agree.
+    if (GVal->getType() != GA->getType())
+      return Error(
+          ExplicitTypeLoc,
+          "forward reference and definition of alias have different types");
 
     // If they agree, just RAUW the old value with the alias and remove the
     // forward ref info.
-    Val->replaceAllUsesWith(GA.get());
-    Val->eraseFromParent();
-    ForwardRefVals.erase(I);
+    GVal->replaceAllUsesWith(GA.get());
+    GVal->eraseFromParent();
   }
 
   // Insert into the module, we know its name won't collide now.
@@ -809,7 +818,7 @@ bool LLParser::ParseGlobal(const std::st
   if (!Name.empty()) {
     GVal = M->getNamedValue(Name);
     if (GVal) {
-      if (!ForwardRefVals.erase(Name) || !isa<GlobalValue>(GVal))
+      if (!ForwardRefVals.erase(Name))
         return Error(NameLoc, "redefinition of global '@" + Name + "'");
     }
   } else {

Modified: llvm/trunk/test/Assembler/alias-redefinition.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Assembler/alias-redefinition.ll?rev=254054&r1=254053&r2=254054&view=diff
==============================================================================
--- llvm/trunk/test/Assembler/alias-redefinition.ll (original)
+++ llvm/trunk/test/Assembler/alias-redefinition.ll Tue Nov 24 20:54:07 2015
@@ -1,6 +1,6 @@
 ; RUN: not llvm-as %s 2>&1 | FileCheck %s
 
-; CHECK: error: redefinition of global named '@bar'
+; CHECK: error: redefinition of global '@bar'
 
 @foo = global i32 0
 @bar = alias i32, i32* @foo

Modified: llvm/trunk/test/Assembler/unnamed-alias.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Assembler/unnamed-alias.ll?rev=254054&r1=254053&r2=254054&view=diff
==============================================================================
--- llvm/trunk/test/Assembler/unnamed-alias.ll (original)
+++ llvm/trunk/test/Assembler/unnamed-alias.ll Tue Nov 24 20:54:07 2015
@@ -5,7 +5,7 @@
 @1 = private constant i32 1
 ; CHECK: @1 = private constant i32 1
 
- at 2 = private alias i32, i32* @0
-; CHECK: @2 = private alias i32, i32* @0
+ at 2 = private alias i32, i32* @3
+; CHECK: @2 = private alias i32, i32* @3
 @3 = private alias i32, i32* @1
 ; CHECK: @3 = private alias i32, i32* @1