[llvm] [llvm-exegesis] Refactor MMAP platform-specific preprocessor directives (PR #75422)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/75422

This patch refactors the MMAP platform-specific preprocessor directives in llvm-exegesis to a single file instead of having duplicate code split across multiple files. These originally got introduced to get buildbots green again due to platform specific failures.

>From fb0a3179de859bb829f39f46758ee751fbfddd7a Mon Sep 17 00:00:00 2001
From: Aiden Grossman <agrossman154 at yahoo.com>
Date: Wed, 13 Dec 2023 18:00:23 -0800
Subject: [PATCH] [llvm-exegesis] Refactor MMAP platform-specific preprocessor
 directives

This patch refactors the MMAP platform-specific preprocessor directives
in llvm-exegesis to a single file instead of having duplicate code split
across multiple files.
---
 llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp  |  7 -------
 llvm/tools/llvm-exegesis/lib/Target.h             | 15 +++++++++++++++
 llvm/tools/llvm-exegesis/lib/X86/Target.cpp       | 15 ---------------
 .../tools/llvm-exegesis/X86/TargetTest.cpp        | 15 ---------------
 4 files changed, 15 insertions(+), 37 deletions(-)

diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index 7bb0218ed53386..313a0e801d4612 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -45,13 +45,6 @@
 #define GLIBC_INITS_RSEQ
 #endif
 #endif
-
-// Before kernel 4.17, Linux did not support MAP_FIXED_NOREPLACE, so if it is
-// not available, simplfy define it as MAP_FIXED which performs the same
-// function but does not guarantee existing mappings won't get clobbered.
-#ifndef MAP_FIXED_NOREPLACE
-#define MAP_FIXED_NOREPLACE MAP_FIXED
-#endif
 #endif // __linux__
 
 namespace llvm {
diff --git a/llvm/tools/llvm-exegesis/lib/Target.h b/llvm/tools/llvm-exegesis/lib/Target.h
index c37dd8b7082162..ab1c713d5c6998 100644
--- a/llvm/tools/llvm-exegesis/lib/Target.h
+++ b/llvm/tools/llvm-exegesis/lib/Target.h
@@ -32,6 +32,21 @@
 #include "llvm/TargetParser/SubtargetFeature.h"
 #include "llvm/TargetParser/Triple.h"
 
+// Before kernel 4.17, Linux did not support MAP_FIXED_NOREPLACE, so if it is
+// not available, simplfy define it as MAP_FIXED which performs the same
+// function but does not guarantee existing mappings won't get clobbered.
+#ifndef MAP_FIXED_NOREPLACE
+#define MAP_FIXED_NOREPLACE MAP_FIXED
+#endif
+
+// Some 32-bit architectures don't have mmap and define mmap2 instead. The only
+// difference between the two syscalls is that mmap2's offset parameter is in
+// terms 4096 byte offsets rather than individual bytes, so for our purposes
+// they are effectively the same as all ofsets here are set to 0.
+#if defined(SYS_mmap2) && !defined(SYS_mmap)
+#define SYS_mmap SYS_mmap2
+#endif
+
 namespace llvm {
 namespace exegesis {
 
diff --git a/llvm/tools/llvm-exegesis/lib/X86/Target.cpp b/llvm/tools/llvm-exegesis/lib/X86/Target.cpp
index 73c0f5430d80d1..d6e897cd5085f6 100644
--- a/llvm/tools/llvm-exegesis/lib/X86/Target.cpp
+++ b/llvm/tools/llvm-exegesis/lib/X86/Target.cpp
@@ -1080,21 +1080,6 @@ ExegesisX86Target::generateExitSyscall(unsigned ExitCode) const {
   return ExitCallCode;
 }
 
-// Before kernel 4.17, Linux did not support MAP_FIXED_NOREPLACE, so if it is
-// not available, simplfy define it as MAP_FIXED which performs the same
-// function but does not guarantee existing mappings won't get clobbered.
-#ifndef MAP_FIXED_NOREPLACE
-#define MAP_FIXED_NOREPLACE MAP_FIXED
-#endif
-
-// Some 32-bit architectures don't have mmap and define mmap2 instead. The only
-// difference between the two syscalls is that mmap2's offset parameter is in
-// terms 4096 byte offsets rather than individual bytes, so for our purposes
-// they are effectively the same as all ofsets here are set to 0.
-#if defined(SYS_mmap2) && !defined(SYS_mmap)
-#define SYS_mmap SYS_mmap2
-#endif
-
 std::vector<MCInst>
 ExegesisX86Target::generateMmap(intptr_t Address, size_t Length,
                                 intptr_t FileDescriptorAddress) const {
diff --git a/llvm/unittests/tools/llvm-exegesis/X86/TargetTest.cpp b/llvm/unittests/tools/llvm-exegesis/X86/TargetTest.cpp
index ff0810e984dd78..bcddb570a0e98f 100644
--- a/llvm/unittests/tools/llvm-exegesis/X86/TargetTest.cpp
+++ b/llvm/unittests/tools/llvm-exegesis/X86/TargetTest.cpp
@@ -625,21 +625,6 @@ TEST_F(X86Core2TargetTest, GenerateExitSyscallTest) {
                           OpcodeIs(X86::SYSCALL)));
 }
 
-// Before kernel 4.17, Linux did not support MAP_FIXED_NOREPLACE, so if it is
-// not available, simplfy define it as MAP_FIXED which performs the same
-// function but does not guarantee existing mappings won't get clobbered.
-#ifndef MAP_FIXED_NOREPLACE
-#define MAP_FIXED_NOREPLACE MAP_FIXED
-#endif
-
-// Some 32-bit architectures don't have mmap and define mmap2 instead. The only
-// difference between the two syscalls is that mmap2's offset parameter is in
-// terms 4096 byte offsets rather than individual bytes, so for our purposes
-// they are effectively the same as all ofsets here are set to 0.
-#if defined(SYS_mmap2) && !defined(SYS_mmap)
-#define SYS_mmap SYS_mmap2
-#endif
-
 TEST_F(X86Core2TargetTest, GenerateMmapTest) {
   EXPECT_THAT(State.getExegesisTarget().generateMmap(0x1000, 4096, 0x2000),
               ElementsAre(IsMovImmediate(X86::MOV64ri, X86::RDI, 0x1000),