[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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@352050 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/AST/ASTStructuralEquivalence.cpp b/lib/AST/ASTStructuralEquivalence.cpp
index 2f00d5adb137f1a67f4a2caf84240bdf3e8eb9bc..7b62eb886210cd122d9d0e3bdd9f10fa3713d348 100644 (file)
--- a/lib/AST/ASTStructuralEquivalence.cpp
+++ b/lib/AST/ASTStructuralEquivalence.cpp
@@ -296,6 +296,32 @@ static bool IsArrayStructurallyEquivalent(StructuralEquivalenceContext &Context,
   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(StructuralEquivalenceContext &Context,
     if (!IsStructurallyEquivalent(Context, Function1->getReturnType(),
                                   Function2->getReturnType()))
       return false;
-    if (Function1->getExtInfo() != Function2->getExtInfo())
+    if (!IsStructurallyEquivalent(Context, Function1->getExtInfo(),
+                                  Function2->getExtInfo()))
       return false;
     break;
   }

diff --git a/unittests/AST/StructuralEquivalenceTest.cpp b/unittests/AST/StructuralEquivalenceTest.cpp
index cd1f01d4bfc691dad63d845d74ba3c646698cc19..c895f7a021a8b2c330fd344cb67c270b1d3585aa 100644 (file)
--- a/unittests/AST/StructuralEquivalenceTest.cpp
+++ b/unittests/AST/StructuralEquivalenceTest.cpp
@@ -370,6 +370,31 @@ TEST_F(StructuralEquivalenceFunctionTest, NameInParenWithConst) {
   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 {
 };