[llvm] HP PA-RISC architecture initial build support (PR #121220)

[Helge Deller via llvm-commits]

https://github.com/hdeller created https://github.com/llvm/llvm-project/pull/121220

Two small patches, which allows to sucessfully build the basic LLVM tools on the HP PA-RISC (hppa) architecture.
Please pull.
Thanks!
Helge

>From ff239dba9a9358b818ab0d37d6271fcfe7619c81 Mon Sep 17 00:00:00 2001
From: Helge <deller at pacific.purple-cat.net>
Date: Fri, 20 Dec 2024 16:40:55 +0000
Subject: [PATCH 1/2] Cmake: Allow build on HP PA-RISC host machine

Fix this configure stage error:
-- LLVM host triple: hppa1.1-unknown-linux-gnu
CMake Error at cmake/config-ix.cmake:516 (message):
  Unknown architecture hppa1.1
---
 llvm/cmake/config-ix.cmake | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
index 64878d28d9e1e5..1dbb468a460447 100644
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -512,6 +512,10 @@ elseif (LLVM_NATIVE_ARCH STREQUAL "m68k")
   set(LLVM_NATIVE_ARCH M68k)
 elseif (LLVM_NATIVE_ARCH MATCHES "loongarch")
   set(LLVM_NATIVE_ARCH LoongArch)
+elseif (LLVM_NATIVE_ARCH MATCHES "hppa1.1")
+  set(LLVM_NATIVE_ARCH HPPA)
+elseif (LLVM_NATIVE_ARCH MATCHES "hppa64")
+  set(LLVM_NATIVE_ARCH HPPA)
 else ()
   message(FATAL_ERROR "Unknown architecture ${LLVM_NATIVE_ARCH}")
 endif ()

>From 4c2413dfe3abeb34e285f3504ac8e0d2937dac78 Mon Sep 17 00:00:00 2001
From: Helge Deller <deller at parisc.parisc-linux.org>
Date: Fri, 20 Dec 2024 21:42:05 +0000
Subject: [PATCH 2/2] Add clock counter for hppa architecture

Add support for time measurements on hppa, otherwise build breaks with this
compiler error:
 You need to define CycleTimer for your OS and CPU
---
 third-party/benchmark/src/cycleclock.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/third-party/benchmark/src/cycleclock.h b/third-party/benchmark/src/cycleclock.h
index d4f1330b671db9..723a3bd17094de 100644
--- a/third-party/benchmark/src/cycleclock.h
+++ b/third-party/benchmark/src/cycleclock.h
@@ -228,6 +228,16 @@ inline BENCHMARK_ALWAYS_INLINE int64_t Now() {
   struct timeval tv;
   gettimeofday(&tv, nullptr);
   return static_cast<int64_t>(tv.tv_sec) * 1000000 + tv.tv_usec;
+#elif defined(__hppa__)
+  // HP PA-RISC provides a user-readable clock counter (cr16), but
+  // it's not syncronized across CPUs and only 32-bit wide when programs
+  // are built as 32-bit binaries.
+  // Use clock_gettime(CLOCK_MONOTONIC, ...) instead of gettimeofday
+  // because is provides nanosecond resolution.
+  // Initialize to always return 0 if clock_gettime fails.
+  struct timespec ts = {0, 0};
+  clock_gettime(CLOCK_MONOTONIC, &ts);
+  return static_cast<int64_t>(ts.tv_sec) * 1000000000 + ts.tv_nsec;
 #else
   // The soft failover to a generic implementation is automatic only for ARM.
   // For other platforms the developer is expected to make an attempt to create