[compiler-rt] [scudo] Add support for LoongArch hardware CRC32 checksumming (PR #83113)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: WÁNG Xuěruì (xen0n)

<details>
<summary>Changes</summary>

The support is available for processors implementing the LoongArch64 subset, but one still has to probe for platform capability prior to use, according to LoongArch documentation.

---
Full diff: https://github.com/llvm/llvm-project/pull/83113.diff


3 Files Affected:

- (modified) compiler-rt/lib/scudo/standalone/checksum.cpp (+10) 
- (modified) compiler-rt/lib/scudo/standalone/checksum.h (+4) 
- (modified) compiler-rt/lib/scudo/standalone/crc32_hw.cpp (+7) 


``````````diff
diff --git a/compiler-rt/lib/scudo/standalone/checksum.cpp b/compiler-rt/lib/scudo/standalone/checksum.cpp
index 2c277391a2ec16..09fa5417653a7a 100644
--- a/compiler-rt/lib/scudo/standalone/checksum.cpp
+++ b/compiler-rt/lib/scudo/standalone/checksum.cpp
@@ -19,6 +19,8 @@
 #else
 #include <sys/auxv.h>
 #endif
+#elif defined(__loongarch_lp64)
+#include <sys/auxv.h>
 #endif
 
 namespace scudo {
@@ -75,6 +77,14 @@ bool hasHardwareCRC32() {
   return !!(getauxval(AT_HWCAP) & HWCAP_CRC32);
 #endif // SCUDO_FUCHSIA
 }
+#elif defined(__loongarch_lp64)
+// Query HWCAP for platform capability, according to *Software Development and
+// Build Convention for LoongArch Architectures* v0.1, Section 9.1.
+//
+// Link: https://github.com/loongson/la-softdev-convention/blob/v0.1/la-softdev-convention.adoc#kernel-development
+bool hasHardwareCRC32() {
+  return !!(getauxval(AT_HWCAP) & HWCAP_LOONGARCH_CRC32);
+}
 #else
 // No hardware CRC32 implemented in Scudo for other architectures.
 bool hasHardwareCRC32() { return false; }
diff --git a/compiler-rt/lib/scudo/standalone/checksum.h b/compiler-rt/lib/scudo/standalone/checksum.h
index f8eda81fd91288..b5f97fe5111f04 100644
--- a/compiler-rt/lib/scudo/standalone/checksum.h
+++ b/compiler-rt/lib/scudo/standalone/checksum.h
@@ -30,6 +30,10 @@
 #include <arm_acle.h>
 #define CRC32_INTRINSIC FIRST_32_SECOND_64(__crc32cw, __crc32cd)
 #endif
+#ifdef __loongarch_lp64
+#include <larchintrin.h>
+#define CRC32_INTRINSIC FIRST_32_SECOND_64(__crcc_w_w_w, __crcc_w_d_w)
+#endif
 
 namespace scudo {
 
diff --git a/compiler-rt/lib/scudo/standalone/crc32_hw.cpp b/compiler-rt/lib/scudo/standalone/crc32_hw.cpp
index 73f2ae000c63d6..3f8c423fa0f49e 100644
--- a/compiler-rt/lib/scudo/standalone/crc32_hw.cpp
+++ b/compiler-rt/lib/scudo/standalone/crc32_hw.cpp
@@ -17,4 +17,11 @@ u32 computeHardwareCRC32(u32 Crc, uptr Data) {
 #endif // defined(__CRC32__) || defined(__SSE4_2__) ||
        // defined(__ARM_FEATURE_CRC32)
 
+#if defined(__loongarch_lp64)
+u32 computeHardwareCRC32(u32 Crc, uptr Data) {
+  // The LoongArch CRC intrinsics have the two input arguments swapped.
+  return static_cast<u32>(CRC32_INTRINSIC(Data, Crc));
+}
+#endif // defined(__loongarch_lp64)
+
 } // namespace scudo

``````````

</details>


https://github.com/llvm/llvm-project/pull/83113