android: jit: teach fallback_cpu_detection provide meaningful results for aarch64

Utilities/JIT.h

@@ -569,6 +569,6 @@ public:
 	bool add_sub_disk_space(ssz space);
 };
 
-llvm::StringRef fallback_cpu_detection();
+const char *fallback_cpu_detection();
 
 #endif // LLVM_AVAILABLE

Utilities/JITLLVM.cpp

@@ -46,6 +46,10 @@ LOG_CHANNEL(jit_log, "JIT");
 #pragma GCC diagnostic pop
 #endif
 
+#ifdef ARCH_ARM64
+#include "Emu/CPU/Backends/AArch64/AArch64Common.h"
+#endif
+
 const bool jit_initialize = []() -> bool
 {
 	llvm::InitializeNativeTarget();
@@ -590,8 +594,10 @@ std::string jit_compiler::triple1()
 	return llvm::Triple::normalize(llvm::sys::getProcessTriple());
 #elif defined(__APPLE__) && defined(ARCH_X64)
 	return llvm::Triple::normalize("x86_64-unknown-linux-gnu");
-#elif defined(__APPLE__) && defined(ARCH_ARM64)
+#elif (defined(__ANDROID__) || defined(__APPLE__)) && defined(ARCH_ARM64)
 	return llvm::Triple::normalize("aarch64-unknown-linux-android"); // Set environment to android to reserve x18
+#elif defined(__ANDROID__) && defined(ARCH_X64)
+	return llvm::Triple::normalize("x86_64-unknown-linux-android");
 #else
 	return llvm::Triple::normalize(llvm::sys::getProcessTriple());
 #endif
@@ -605,8 +611,10 @@ std::string jit_compiler::triple2()
 	return llvm::Triple::normalize("aarch64-unknown-linux-gnu");
 #elif defined(__APPLE__) && defined(ARCH_X64)
 	return llvm::Triple::normalize("x86_64-unknown-linux-gnu");
-#elif defined(__APPLE__) && defined(ARCH_ARM64)
+#elif (defined(__ANDROID__) || defined(__APPLE__)) && defined(ARCH_ARM64)
 	return llvm::Triple::normalize("aarch64-unknown-linux-android"); // Set environment to android to reserve x18
+#elif defined(__ANDROID__) && defined(ARCH_X64)
+	return llvm::Triple::normalize("x86_64-unknown-linux-android"); // Set environment to android to reserve x18
 #else
 	return llvm::Triple::normalize(llvm::sys::getProcessTriple());
 #endif
@@ -817,9 +825,9 @@ u64 jit_compiler::get(const std::string& name)
 	return m_engine->getGlobalValueAddress(name);
 }
 
-llvm::StringRef fallback_cpu_detection()
+const char * fallback_cpu_detection()
 {
-#if defined (ARCH_X64)
+#if defined(ARCH_X64)
 	// If we got here we either have a very old and outdated CPU or a new CPU that has not been seen by LLVM yet.
 	const std::string brand = utils::get_cpu_brand();
 	const auto family = utils::get_cpu_family();
@@ -851,8 +859,8 @@ llvm::StringRef fallback_cpu_detection()
 		default:
 		 	// Safest guesses
 			return utils::has_avx512() ? "znver4" :
-				utils::has_avx2() ? "znver1" :
-				utils::has_avx() ? "bdver1" :
+			       utils::has_avx2()   ? "znver1" :
+			       utils::has_avx()    ? "bdver1" :
 				"nehalem";
 		}
 	}
@@ -883,10 +891,26 @@ llvm::StringRef fallback_cpu_detection()
 	}
 
 #elif defined(ARCH_ARM64)
+#ifdef ANDROID
+	static std::string s_result = []() -> std::string
+	{
+		std::string result = aarch64::get_cpu_name();
+		if (result.empty())
+		{
+			return "cortex-a78";
+		}
+
+		std::transform(result.begin(), result.end(), result.begin(), ::tolower);
+		return result;
+	}();
+
+	return s_result.c_str();
+#else
 	// TODO: Read the data from /proc/cpuinfo. ARM CPU registers are not accessible from usermode.
 	// This will be a pain when supporting snapdragon on windows but we'll cross that bridge when we get there.
 	// Require at least armv8-2a. Older chips are going to be useless anyway.
 	return "cortex-a78";
+#endif
 #endif
 
 	// Failed to guess, use generic fallback

rpcs3/Emu/CPU/Backends/AArch64/AArch64Common.cpp

@@ -136,6 +136,45 @@ namespace aarch64
 #endif
     }
 
+    std::string get_cpu_name()
+    {
+        std::map<u64, int> core_layout;
+        for (u32 i = 0; i < std::thread::hardware_concurrency(); ++i)
+        {
+            const auto midr = read_MIDR_EL1(i);
+            if (midr == umax)
+            {
+                break;
+            }
+
+            core_layout[midr]++;
+        }
+
+        if (core_layout.empty())
+        {
+            return {};
+        }
+
+        const cpu_entry_t *lowest_part_info = nullptr; 
+        for (const auto& [midr, count] : core_layout)
+        {
+            const auto implementer_id = (midr >> 24) & 0xff;
+            const auto part_id = (midr >> 4) & 0xfff;
+
+            const auto part_info = find_cpu_part(implementer_id, part_id);
+            if (!part_info)
+            {
+                return {};
+            }
+
+            if (lowest_part_info == nullptr || lowest_part_info > part_info) {
+                lowest_part_info = part_info;
+            }
+        }
+
+        return lowest_part_info == nullptr ? "" : lowest_part_info->name;
+    }
+
     std::string get_cpu_brand()
     {
         // Fetch vendor and part numbers. ARM CPUs often have more than 1 architecture on the SoC, so we check all of them.

rpcs3/Emu/CPU/Backends/AArch64/AArch64Common.h

@@ -37,5 +37,6 @@ namespace aarch64
         "xzr", ".", "sp"
     };
 
+    std::string get_cpu_name();
     std::string get_cpu_brand();
 }