[libc++] [test] Fix a few tests for 32-bit x86

[hvdijk]

Summary

• libcxx/gdb/gdb_pretty_printer_test.sh.cpp tests that vectors pretty-print correctly, but the exact output depends on the target: vector<bool> stores its bits in an array of __storage_type, which may be 32 bits.
• The unique_ptr_ret and weak_ptr_ret tests are not expected to pass on x86. These tests check that unique_ptr and weak_ptr are returned by value, but on x86, all structs are always returned by reference.

Fixes bug 48939.

[curdeius]

LGTM. But please rebase to rerun CI (the commit that provoked the failures has been reverted).
It would be cool if @saugustine could have a look at gdb part though. @ldionne, this patch should unblock adding 32-bit buildbots to CI in D92508.

[curdeius]

Also, please update https://bugs.llvm.org/show_bug.cgi?id=48939 and add it to the description.

[hvdijk]

This diff is identical to the previous diff, but hopefully a reupload will redo the CI.

[hvdijk]

Should I continue waiting for @saugustine to check the gdb part of this? If it takes too long to get that reviewed it might be better if I split this in two so that I can at least commit the non-gdb parts already.

[ldionne]

libcxx/test/libcxx/memory/trivial_abi/unique_ptr_ret.pass.cpp

18

Can we instead use // XFAIL: target-x86?

[hvdijk]

libcxx/test/libcxx/memory/trivial_abi/unique_ptr_ret.pass.cpp

18

Marking this as XFAIL would suggest to me that there is a bug that we're ignoring for now. I don't think there is: _LIBCPP_ABI_ENABLE_UNIQUE_PTR_TRIVIAL_ABI is behaving exactly as intended, unique_ptr is passed exactly as a trivial type.

[ldionne]

libcxx/test/libcxx/memory/trivial_abi/unique_ptr_ret.pass.cpp

18

XFAIL is also used when the test is expected to fail because the tested behavior doesn't apply to the given configuration - or at least we've been using it for that. But I can see your point, and I'm fine with the current approach.

libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp

void multiset_test() {
   std::multiset<std::string> one_two_three {"1:one", "2:two", "3:three", "1:one"};
   ComparePrettyPrintToChars(one_two_three,
       "std::multiset with 4 elements = {"
       R"("1:one", "1:one", "2:two", "3:three"})");
 }
 
 void vector_test() {
   std::vector<bool> test0 = {true, false};
-  ComparePrettyPrintToChars(test0,
+  ComparePrettyPrintToRegex(test0,
                             "std::vector<bool> of "
-                            "length 2, capacity 64 = {1, 0}");
+                            "length 2, capacity (32|64) = {1, 0}");
   for (int i = 0; i < 31; ++i) {
     test0.push_back(true);
     test0.push_back(false);
   }
   ComparePrettyPrintToRegex(
       test0,
       "std::vector<bool> of length 64, "
       "capacity 64 = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, "
       "0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, "
       "0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0}");
   test0.push_back(true);
   ComparePrettyPrintToRegex(
       test0,
       "std::vector<bool> of length 65, "
-      "capacity 128 = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, "
-      "1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, "
-      "1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}");
+      "capacity (96|128) = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, "
+      "0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, "
+      "0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}");
 
   std::vector<int> test1;
   ComparePrettyPrintToChars(test1, "std::vector of length 0, capacity 0");
 
   std::vector<int> test2 = {5, 6, 7};
   ComparePrettyPrintToChars(test2,
                             "std::vector of length "
                             "3, capacity 3 = {5, 6, 7}");

libcxx/test/libcxx/memory/trivial_abi/unique_ptr_ret.pass.cpp

 
 // Test unique_ptr<T> with trivial_abi as return-type.
 
 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_ABI_ENABLE_UNIQUE_PTR_TRIVIAL_ABI
 
 // There were assertion failures in both parse and codegen, which are fixed in clang 11.
 // UNSUPPORTED: gcc, clang-4, clang-5, clang-6, clang-7, clang-8, clang-9, clang-10
 
 // XFAIL: LIBCXX-WINDOWS-FIXME
 
 #include <memory>
 #include <cassert>
 
 __attribute__((noinline)) void call_something() { asm volatile(""); }
 
 struct Node {
   explicit Node() {}
int main(int, char**) {
   auto ret = make_val(&local_addr);
   assert(local_addr != nullptr);
 
   // Without trivial_abi, &ret == local_addr because the return value
   // is allocated here in main's stackframe.
   //
   // With trivial_abi, local_addr is the address of a local variable in
   // make_val, and hence different from &ret.
+#if !defined(__i386__)
+  // On X86, structs are never returned in registers.
+  // Thus, unique_ptr will be passed indirectly even if it is trivial.
   assert((void*)&ret != local_addr);
+#endif
 
   return 0;
 }

libcxx/test/libcxx/memory/trivial_abi/weak_ptr_ret.pass.cpp

int main(int, char**) {
   std::weak_ptr<Node> ret = make_val(sptr, &local_addr);
   assert(local_addr != nullptr);
 
   // Without trivial_abi, &ret == local_addr because the return value
   // is allocated here in main's stackframe.
   //
   // With trivial_abi, local_addr is the address of a local variable in
   // make_val, and hence different from &ret.
-#ifndef __arm__
+#if !defined(__i386__) && !defined(__arm__)
+  // On X86, structs are never returned in registers.
   // On ARM32, structs larger than 4 bytes cannot be returned in registers.
-  // Thus, weak_ptr will be passed indrectly even if it is trivial.
+  // Thus, weak_ptr will be passed indirectly even if it is trivial.
   assert((void*)&ret != local_addr);
 #endif
   return 0;
 }