[RISCV][compiler-rt] Update __init_riscv_feature_bits prototype (#101472)

This patch add `void* PlatformArgs` parameter to
`__init_riscv_feature_bits`. `PlatformArgs` allows the platform to
provide pre-computed data and access it without extra effort. For
example, Linux could pass the vDSO object to avoid an extra system call.

```
__init_riscv_feature_bits()

->

__init_riscv_feature_bits(void *PlatformArgs)
```

Author: BeMg

clang/lib/CodeGen/CGBuiltin.cpp

@@ -14370,13 +14370,13 @@ Value *CodeGenFunction::EmitAArch64CpuInit() {
 }
 
 Value *CodeGenFunction::EmitRISCVCpuInit() {
-  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
+  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, {VoidPtrTy}, false);
   llvm::FunctionCallee Func =
       CGM.CreateRuntimeFunction(FTy, "__init_riscv_feature_bits");
   auto *CalleeGV = cast<llvm::GlobalValue>(Func.getCallee());
   CalleeGV->setDSOLocal(true);
   CalleeGV->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
-  return Builder.CreateCall(Func);
+  return Builder.CreateCall(Func, {llvm::ConstantPointerNull::get(VoidPtrTy)});
 }
 
 Value *CodeGenFunction::EmitX86CpuInit() {

clang/test/CodeGen/builtin-cpu-supports.c

@@ -250,7 +250,7 @@ int test_ppc(int a) {
 // CHECK-RV32-NEXT:    [[RETVAL:%.*]] = alloca i32, align 4
 // CHECK-RV32-NEXT:    [[A_ADDR:%.*]] = alloca i32, align 4
 // CHECK-RV32-NEXT:    store i32 [[A]], ptr [[A_ADDR]], align 4
-// CHECK-RV32-NEXT:    call void @__init_riscv_feature_bits()
+// CHECK-RV32-NEXT:    call void @__init_riscv_feature_bits(ptr null)
 // CHECK-RV32-NEXT:    [[TMP0:%.*]] = load i64, ptr getelementptr inbounds ({ i32, [1 x i64] }, ptr @__riscv_feature_bits, i32 0, i32 1, i32 0), align 8
 // CHECK-RV32-NEXT:    [[TMP1:%.*]] = and i64 [[TMP0]], 1
 // CHECK-RV32-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[TMP1]], 1
@@ -301,7 +301,7 @@ int test_ppc(int a) {
 // CHECK-RV64-NEXT:    [[RETVAL:%.*]] = alloca i32, align 4
 // CHECK-RV64-NEXT:    [[A_ADDR:%.*]] = alloca i32, align 4
 // CHECK-RV64-NEXT:    store i32 [[A]], ptr [[A_ADDR]], align 4
-// CHECK-RV64-NEXT:    call void @__init_riscv_feature_bits()
+// CHECK-RV64-NEXT:    call void @__init_riscv_feature_bits(ptr null)
 // CHECK-RV64-NEXT:    [[TMP0:%.*]] = load i64, ptr getelementptr inbounds ({ i32, [1 x i64] }, ptr @__riscv_feature_bits, i32 0, i32 1, i32 0), align 8
 // CHECK-RV64-NEXT:    [[TMP1:%.*]] = and i64 [[TMP0]], 1
 // CHECK-RV64-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[TMP1]], 1

compiler-rt/lib/builtins/cpu_model/riscv.c

@@ -328,14 +328,18 @@ static void initRISCVFeature(struct riscv_hwprobe Hwprobes[]) {
 
 static int FeaturesBitCached = 0;
 
-void __init_riscv_feature_bits() CONSTRUCTOR_ATTRIBUTE;
+void __init_riscv_feature_bits(void *) CONSTRUCTOR_ATTRIBUTE;
 
 // A constructor function that sets __riscv_feature_bits, and
 // __riscv_vendor_feature_bits to the right values.  This needs to run
 // only once.  This constructor is given the highest priority and it should
 // run before constructors without the priority set.  However, it still runs
 // after ifunc initializers and needs to be called explicitly there.
-void CONSTRUCTOR_ATTRIBUTE __init_riscv_feature_bits() {
+
+// PlatformArgs allows the platform to provide pre-computed data and access it
+// without extra effort. For example, Linux could pass the vDSO object to avoid
+// an extra system call.
+void CONSTRUCTOR_ATTRIBUTE __init_riscv_feature_bits(void *PlatformArgs) {
 
   if (FeaturesBitCached)
     return;