r352050 - [ASTImporter] Fix inequality of functions with different attributes

[Gabor Marton via cfe-commits]

Author: martong
Date: Thu Jan 24 06:47:44 2019
New Revision: 352050

URL: http://llvm.org/viewvc/llvm-project?rev=352050&view=rev
Log:
[ASTImporter] Fix inequality of functions with different attributes

Summary:
FunctionType::ExtInfo holds such properties of a function which are needed
mostly for code gen. We should not compare these bits when checking for
structural equivalency.
Checking ExtInfo caused false ODR errors during CTU analysis (of tmux).

Reviewers: a_sidorin, a.sidorin, shafik

Subscribers: rnkovacs, dkrupp, Szelethus, cfe-commits

Differential Revision: https://reviews.llvm.org/D53699

Modified:
    cfe/trunk/lib/AST/ASTStructuralEquivalence.cpp
    cfe/trunk/unittests/AST/StructuralEquivalenceTest.cpp

Modified: cfe/trunk/lib/AST/ASTStructuralEquivalence.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTStructuralEquivalence.cpp?rev=352050&r1=352049&r2=352050&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ASTStructuralEquivalence.cpp (original)
+++ cfe/trunk/lib/AST/ASTStructuralEquivalence.cpp Thu Jan 24 06:47:44 2019
@@ -296,6 +296,32 @@ static bool IsArrayStructurallyEquivalen
   return true;
 }
 
+/// Determine structural equivalence based on the ExtInfo of functions. This
+/// is inspired by ASTContext::mergeFunctionTypes(), we compare calling
+/// conventions bits but must not compare some other bits.
+static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
+                                     FunctionType::ExtInfo EI1,
+                                     FunctionType::ExtInfo EI2) {
+  // Compatible functions must have compatible calling conventions.
+  if (EI1.getCC() != EI2.getCC())
+    return false;
+
+  // Regparm is part of the calling convention.
+  if (EI1.getHasRegParm() != EI2.getHasRegParm())
+    return false;
+  if (EI1.getRegParm() != EI2.getRegParm())
+    return false;
+
+  if (EI1.getProducesResult() != EI2.getProducesResult())
+    return false;
+  if (EI1.getNoCallerSavedRegs() != EI2.getNoCallerSavedRegs())
+    return false;
+  if (EI1.getNoCfCheck() != EI2.getNoCfCheck())
+    return false;
+
+  return true;
+}
+
 /// Determine structural equivalence of two types.
 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
                                      QualType T1, QualType T2) {
@@ -539,7 +565,8 @@ static bool IsStructurallyEquivalent(Str
     if (!IsStructurallyEquivalent(Context, Function1->getReturnType(),
                                   Function2->getReturnType()))
       return false;
-    if (Function1->getExtInfo() != Function2->getExtInfo())
+    if (!IsStructurallyEquivalent(Context, Function1->getExtInfo(),
+                                  Function2->getExtInfo()))
       return false;
     break;
   }

Modified: cfe/trunk/unittests/AST/StructuralEquivalenceTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/AST/StructuralEquivalenceTest.cpp?rev=352050&r1=352049&r2=352050&view=diff
==============================================================================
--- cfe/trunk/unittests/AST/StructuralEquivalenceTest.cpp (original)
+++ cfe/trunk/unittests/AST/StructuralEquivalenceTest.cpp Thu Jan 24 06:47:44 2019
@@ -370,6 +370,31 @@ TEST_F(StructuralEquivalenceFunctionTest
   EXPECT_FALSE(testStructuralMatch(t));
 }
 
+TEST_F(StructuralEquivalenceFunctionTest, FunctionsWithDifferentNoreturnAttr) {
+  auto t = makeNamedDecls(
+      "__attribute__((noreturn)) void foo();",
+      "                          void foo();",
+      Lang_C);
+  EXPECT_TRUE(testStructuralMatch(t));
+}
+
+TEST_F(StructuralEquivalenceFunctionTest,
+    FunctionsWithDifferentCallingConventions) {
+  auto t = makeNamedDecls(
+      "__attribute__((fastcall)) void foo();",
+      "__attribute__((ms_abi))   void foo();",
+      Lang_C);
+  EXPECT_FALSE(testStructuralMatch(t));
+}
+
+TEST_F(StructuralEquivalenceFunctionTest, FunctionsWithDifferentSavedRegsAttr) {
+  auto t = makeNamedDecls(
+      "__attribute__((no_caller_saved_registers)) void foo();",
+      "                                           void foo();",
+      Lang_C);
+  EXPECT_FALSE(testStructuralMatch(t));
+}
+
 struct StructuralEquivalenceCXXMethodTest : StructuralEquivalenceTest {
 };