[lldb/ArchSpec] Always match simulator environment in IsEqualTo

[friss]

Summary

Initially, Apple simulator binarie triples didn't use a -simulator
environment and were just differentiated based on the architecture.
For example, x86_64-apple-ios would obviously be a simualtor as iOS
doesn't run on x86_64. With Catalyst, we made the disctinction
explicit and today, all simulator triples (even the legacy ones) are
constructed with an environment. This is especially important on Apple
Silicon were the architecture is not different from the one of the
simulated device.

This change makes the simulator part of the environment always part of
the criteria to detect whether 2 ArchSpecs are equal or compatible.

[aprantl]

Yes, this makes perfect sense. Thanks!

lldb/unittests/Utility/ArchSpecTest.cpp

329

What's to fix here?

[friss]

lldb/unittests/Utility/ArchSpecTest.cpp

329

Aren't you the one who introduced this comment? I can move my new test one slot up so it makes this a little less confusing.

[aprantl]

lldb/unittests/Utility/ArchSpecTest.cpp

315

We want to be *really* sure of this? :-)

lldb/source/Utility/ArchSpec.cpp

bool ArchSpec::IsCompatibleMatch(const ArchSpec &rhs) const {
   return IsEqualTo(rhs, false);
 }
 
 static bool IsCompatibleEnvironment(llvm::Triple::EnvironmentType lhs,
                                     llvm::Triple::EnvironmentType rhs) {
   if (lhs == rhs)
     return true;
 
+  // Apple simulators are a different platform than what they simulate.
+  // As the environments are different at this point, if one of them is a
+  // simulator, then they are different.
+  if (lhs == llvm::Triple::Simulator || rhs == llvm::Triple::Simulator)
+    return false;
+
   // If any of the environment is unknown then they are compatible
   if (lhs == llvm::Triple::UnknownEnvironment ||
       rhs == llvm::Triple::UnknownEnvironment)
     return true;
 
   // If one of the environment is Android and the other one is EABI then they
   // are considered to be compatible. This is required as a workaround for
   // shared libraries compiled for Android without the NOTE section indicating

lldb/unittests/Utility/ArchSpecTest.cpp

TEST(ArchSpecTest, Compatibility) {
   }
   {
     ArchSpec A("x86_64-*-*");
     ArchSpec B("x86_64-apple-ios-simulator");
     ASSERT_FALSE(A.IsExactMatch(B));
     ASSERT_FALSE(A.IsCompatibleMatch(B));
   }
   {
+    ArchSpec A("arm64-apple-ios");
+    ArchSpec B("arm64-apple-ios-simulator");
+    ASSERT_FALSE(A.IsExactMatch(B));
+    ASSERT_FALSE(A.IsCompatibleMatch(B));
+    ASSERT_FALSE(B.IsCompatibleMatch(A));
+    ASSERT_FALSE(B.IsCompatibleMatch(A));
+  }
+  {
     ArchSpec A("arm64-*-*");
     ArchSpec B("arm64-apple-ios");
     ASSERT_FALSE(A.IsExactMatch(B));
     // FIXME: This looks unintuitive and we should investigate whether
     // this is the desired behavior.
     ASSERT_FALSE(A.IsCompatibleMatch(B));
   }
   {
     ArchSpec A("x86_64-*-*");
     ArchSpec B("x86_64-apple-ios-simulator");
     ASSERT_FALSE(A.IsExactMatch(B));
     // FIXME: See above, though the extra environment complicates things.
     ASSERT_FALSE(A.IsCompatibleMatch(B));
   }
   {
     ArchSpec A("x86_64");
     ArchSpec B("x86_64-apple-macosx10.14");
     // FIXME: The exact match also looks unintuitive.
     ASSERT_TRUE(A.IsExactMatch(B));
     ASSERT_TRUE(A.IsCompatibleMatch(B));