From 191570989ba291c639034906eeb6a0bae9ed47e9 Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Wed, 28 Apr 2021 13:15:39 -0700
Subject: Improve error messages for attributes in the wrong context.

verifyFunctionAttrs has a comment that the value V is printed in error messages. The recently added errors for attributes didn't print V. Make them print V.

Change the stringification of AttributeList. Firstly they started with 'PAL[' which stood for ParamAttrsList. Change that to 'AttributeList[' matching its current name AttributeList. Print out semantic meaning of the index instead of the raw index value (i.e. 'return', 'function' or 'arg(n)').
---
 llvm/lib/IR/Attributes.cpp           | 18 +++++++++++++++---
 llvm/lib/IR/Verifier.cpp             |  6 +++---
 llvm/unittests/IR/AttributesTest.cpp | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 30730a4374a5..324e6f183334 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -1693,11 +1693,23 @@ unsigned AttributeList::getNumAttrSets() const {
 }
 
 void AttributeList::print(raw_ostream &O) const {
-  O << "PAL[\n";
+  O << "AttributeList[\n";
 
   for (unsigned i = index_begin(), e = index_end(); i != e; ++i) {
-    if (getAttributes(i).hasAttributes())
-      O << "  { " << i << " => " << getAsString(i) << " }\n";
+    if (getAttributes(i).hasAttributes()) {
+      O << "  { ";
+      switch (i) {
+      case AttrIndex::ReturnIndex:
+        O << "return";
+        break;
+      case AttrIndex::FunctionIndex:
+        O << "function";
+        break;
+      default:
+          O << "arg(" << i - AttrIndex::FirstArgIndex << ")";
+      }
+      O << " => " << getAsString(i) << " }\n";
+    }
   }
 
   O << "]\n";
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index e83599f7d08f..856d1896489f 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -1895,13 +1895,13 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
 
   if (AttributeListsVisited.insert(Attrs.getRawPointer()).second) {
     Assert(Attrs.hasParentContext(Context),
-           "Attribute list does not match Module context!", &Attrs);
+           "Attribute list does not match Module context!", &Attrs, V);
     for (const auto &AttrSet : Attrs) {
       Assert(!AttrSet.hasAttributes() || AttrSet.hasParentContext(Context),
-             "Attribute set does not match Module context!", &AttrSet);
+             "Attribute set does not match Module context!", &AttrSet, V);
       for (const auto &A : AttrSet) {
         Assert(A.hasParentContext(Context),
-               "Attribute does not match Module context!", &A);
+               "Attribute does not match Module context!", &A, V);
       }
     }
   }
diff --git a/llvm/unittests/IR/AttributesTest.cpp b/llvm/unittests/IR/AttributesTest.cpp
index 03b4cef404f5..f260f0f9bf86 100644
--- a/llvm/unittests/IR/AttributesTest.cpp
+++ b/llvm/unittests/IR/AttributesTest.cpp
@@ -217,4 +217,39 @@ TEST(Attributes, HasParentContext) {
   }
 }
 
+TEST(Attributes, AttributeListPrinting) {
+  LLVMContext C;
+
+  {
+    std::string S;
+    raw_string_ostream OS(S);
+    AttributeList AL;
+    AL.addAttribute(C, AttributeList::FunctionIndex, Attribute::AlwaysInline)
+        .print(OS);
+    EXPECT_EQ(S, "AttributeList[\n"
+                 "  { function => alwaysinline }\n"
+                 "]\n");
+  }
+
+  {
+    std::string S;
+    raw_string_ostream OS(S);
+    AttributeList AL;
+    AL.addAttribute(C, AttributeList::ReturnIndex, Attribute::SExt).print(OS);
+    EXPECT_EQ(S, "AttributeList[\n"
+                 "  { return => signext }\n"
+                 "]\n");
+  }
+
+  {
+    std::string S;
+    raw_string_ostream OS(S);
+    AttributeList AL;
+    AL.addParamAttribute(C, 5, Attribute::ZExt).print(OS);
+    EXPECT_EQ(S, "AttributeList[\n"
+                 "  { arg(5) => zeroext }\n"
+                 "]\n");
+  }
+}
+
 } // end anonymous namespace
-- 
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