[llvm] [llvm-exegesis][unittests] Disable SubprocessMemoryTest on big-endian… (PR #102755)

[Rainer Orth via llvm-commits]

https://github.com/rorth created https://github.com/llvm/llvm-project/pull/102755

… hosts

Three `llvm-exegesis` tests
```
  LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/SubprocessMemoryTest/DefinitionFillsCompletely
  LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/SubprocessMemoryTest/MultipleDefinitions
  LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/SubprocessMemoryTest/OneDefinition
```
`FAIL` on Linux/sparc64 like
```
llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp:68: Failure
Expected equality of these values:
  SharedMemoryMapping[I]
    Which is: '\0'
  ExpectedValue[I]
    Which is: '\xAA' (170)
```
It seems like this test only works on little-endian hosts: three sub-tests are already disabled on powerpc and s390x (both big-endian), and the fourth is additionally guarded against big-endian hosts (making the other guards unnecessary).

Rather than add big-endian hosts (like sparc) one by one to every sub-test, it seems better to disable the whole test on big-endian.

Tested on `sparc64-unknown-linux-gnu` and `x86_64-pc-linux-gnu`.

>From f694255ce6536aed18487916ecc57d66e202bbdb Mon Sep 17 00:00:00 2001
From: Rainer Orth <ro at gcc.gnu.org>
Date: Sat, 10 Aug 2024 16:39:16 +0200
Subject: [PATCH] [llvm-exegesis][unittests] Disable SubprocessMemoryTest on
 big-endian hosts

Three `llvm-exegesis` tests
```
  LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/SubprocessMemoryTest/DefinitionFillsCompletely
  LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/SubprocessMemoryTest/MultipleDefinitions
  LLVM-Unit :: tools/llvm-exegesis/./LLVMExegesisTests/SubprocessMemoryTest/OneDefinition
```
`FAIL` on Linux/sparc64 like
```
llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp:68: Failure
Expected equality of these values:
  SharedMemoryMapping[I]
    Which is: '\0'
  ExpectedValue[I]
    Which is: '\xAA' (170)
```
It seems like this test only works on little-endian hosts: three
sub-tests are already disabled on powerpc and s390x (both big-endian), and
the fourth is additionaly guarded against big-endian hosts (making the
other guards unnecessary).

Rather than add big-endian hosts (like sparc) one by one to every sub-test,
it seems better to disable the whole test on big-endian.

Tested on `sparc64-unknown-linux-gnu` and `x86_64-pc-linux-gnu`.
---
 .../X86/SubprocessMemoryTest.cpp              | 24 ++++---------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp b/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
index 7c23e7b7e9c5a5..b6dfca2da6c625 100644
--- a/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
+++ b/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
@@ -24,7 +24,9 @@
 namespace llvm {
 namespace exegesis {
 
-#if defined(__linux__) && !defined(__ANDROID__)
+// The tests are only supported on little endian systems.
+#if defined(__linux__) && !defined(__ANDROID__) &&                             \
+    __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 
 // This needs to be updated anytime a test is added or removed from the test
 // suite.
@@ -77,20 +79,12 @@ class SubprocessMemoryTest : public X86TestBase {
 // memory calls not working in some cases, so they have been disabled.
 // TODO(boomanaiden154): Investigate and fix this issue on PPC.
 
-#if defined(__powerpc__) || defined(__s390x__)
-TEST_F(SubprocessMemoryTest, DISABLED_OneDefinition) {
-#else
 TEST_F(SubprocessMemoryTest, OneDefinition) {
-#endif
   testCommon({{"test1", {APInt(8, 0xff), 4096, 0}}}, 0);
   checkSharedMemoryDefinition(getSharedMemoryName(0, 0), 4096, {0xff});
 }
 
-#if defined(__powerpc__) || defined(__s390x__)
-TEST_F(SubprocessMemoryTest, DISABLED_MultipleDefinitions) {
-#else
 TEST_F(SubprocessMemoryTest, MultipleDefinitions) {
-#endif
   testCommon({{"test1", {APInt(8, 0xaa), 4096, 0}},
               {"test2", {APInt(8, 0xbb), 4096, 1}},
               {"test3", {APInt(8, 0xcc), 4096, 2}}},
@@ -100,11 +94,7 @@ TEST_F(SubprocessMemoryTest, MultipleDefinitions) {
   checkSharedMemoryDefinition(getSharedMemoryName(1, 2), 4096, {0xcc});
 }
 
-#if defined(__powerpc__) || defined(__s390x__)
-TEST_F(SubprocessMemoryTest, DISABLED_DefinitionFillsCompletely) {
-#else
 TEST_F(SubprocessMemoryTest, DefinitionFillsCompletely) {
-#endif
   testCommon({{"test1", {APInt(8, 0xaa), 4096, 0}},
               {"test2", {APInt(16, 0xbbbb), 4096, 1}},
               {"test3", {APInt(24, 0xcccccc), 4096, 2}}},
@@ -117,12 +107,7 @@ TEST_F(SubprocessMemoryTest, DefinitionFillsCompletely) {
   checkSharedMemoryDefinition(getSharedMemoryName(2, 2), 4096, Test3Expected);
 }
 
-// The following test is only supported on little endian systems.
-#if defined(__powerpc__) || defined(__s390x__) || __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-TEST_F(SubprocessMemoryTest, DISABLED_DefinitionEndTruncation) {
-#else
 TEST_F(SubprocessMemoryTest, DefinitionEndTruncation) {
-#endif
   testCommon({{"test1", {APInt(48, 0xaabbccddeeff), 4096, 0}}}, 3);
   std::vector<uint8_t> Test1Expected(512, 0);
   // order is reversed since we're assuming a little endian system.
@@ -150,7 +135,8 @@ TEST_F(SubprocessMemoryTest, DefinitionEndTruncation) {
   checkSharedMemoryDefinition(getSharedMemoryName(3, 0), 4096, Test1Expected);
 }
 
-#endif // defined(__linux__) && !defined(__ANDROID__)
+#endif // defined(__linux__) && !defined(__ANDROID__) && __BYTE_ORDER__ ==
+       // __ORDER_LITTLE_ENDIAN__
 
 } // namespace exegesis
 } // namespace llvm