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#include "cps/RuntimeCheck.h"
#include "cps/ExceptionHandler.h"
#include "cps/TypeSystem.h" // kEnumOrdinalBase
#include "llvm/IR/Function.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Constants.h"
using namespace llvm;
using namespace cps;
RuntimeCheck::RuntimeCheck(Module &M, LLVMContext &C, IRBuilder<> &B, ExceptionHandler &EH)
: TheModule(M), TheContext(C), Builder(B), Exceptions(EH) {
setupExternalFunctions();
}
void RuntimeCheck::setupExternalFunctions() {
Type *PtrTy = PointerType::getUnqual(TheContext);
Type *I32 = Type::getInt32Ty(TheContext);
Type *I64 = Type::getInt64Ty(TheContext);
SnprintfFunc = TheModule.getOrInsertFunction(
"snprintf", FunctionType::get(I32, {PtrTy, I64, PtrTy}, true));
WriteFunc = TheModule.getOrInsertFunction(
"write", FunctionType::get(I32, {I32, PtrTy, I64}, false));
StrLenFunc = TheModule.getOrInsertFunction(
"strlen", FunctionType::get(I64, {PtrTy}, false));
ArrayType *BufTy = ArrayType::get(Type::getInt8Ty(TheContext), 1024);
ErrBuf = new GlobalVariable(TheModule, BufTy, false, GlobalValue::InternalLinkage,
ConstantAggregateZero::get(BufTy), "__cps_errbuf");
DivZeroMsg = Builder.CreateGlobalString("[Fatal] line %d: Division by zero\n", "err_div_zero", 0, &TheModule);
OutOfBoundsMsg = Builder.CreateGlobalString("[Fatal] line %d: Array index out of bounds\n", "err_bounds", 0, &TheModule);
EnumRangeMsg = Builder.CreateGlobalString("[Fatal] line %d: Value out of range for enum %s\n", "err_enum_range", 0, &TheModule);
NullDerefMsg = Builder.CreateGlobalString("[Fatal] line %d: Dereference of an unset pointer\n", "err_null_deref", 0, &TheModule);
ArrayArgBoundsMsg = Builder.CreateGlobalString(
"[Fatal] line %d: Array argument bounds [%lld:%lld] do not match the declared parameter bounds [%lld:%lld]\n",
"err_arr_arg_bounds", 0, &TheModule);
}
void RuntimeCheck::emitStderr(Value *Msg, ArrayRef<Value *> FmtArgs) {
// Format into a fixed buffer, then write(2) so diagnostics bypass stdout.
std::vector<Value *> Args = {ErrBuf, ConstantInt::get(Type::getInt64Ty(TheContext), 1024), Msg};
Args.insert(Args.end(), FmtArgs.begin(), FmtArgs.end());
Builder.CreateCall(SnprintfFunc, Args);
Value *Len = Builder.CreateCall(StrLenFunc, {ErrBuf});
Builder.CreateCall(WriteFunc, {ConstantInt::get(Type::getInt32Ty(TheContext), 2), ErrBuf, Len});
}
void RuntimeCheck::emitCheck(Value *Condition, Value *Msg, int Line) {
emitCheck(Condition, Msg, {ConstantInt::get(TheContext, APInt(32, Line))});
}
void RuntimeCheck::emitCheck(Value *Condition, Value *Msg, ArrayRef<Value *> FmtArgs) {
Function *TheFunction = Builder.GetInsertBlock()->getParent();
BasicBlock *FailBB = BasicBlock::Create(TheContext, "check_fail", TheFunction);
BasicBlock *ContBB = BasicBlock::Create(TheContext, "check_cont", TheFunction);
Builder.CreateCondBr(Condition, FailBB, ContBB);
Builder.SetInsertPoint(FailBB);
std::vector<Value*> PrintArgs;
PrintArgs.push_back(Msg);
PrintArgs.insert(PrintArgs.end(), FmtArgs.begin(), FmtArgs.end());
emitStderr(Msg, ArrayRef<Value *>(PrintArgs).drop_front());
Exceptions.emitThrow();
Builder.SetInsertPoint(ContBB);
}
void RuntimeCheck::emitDivZeroCheck(Value *Divisor, int Line) {
Value *IsZero;
if (Divisor->getType()->isFloatingPointTy()) {
IsZero = Builder.CreateFCmpOEQ(Divisor, ConstantFP::get(Divisor->getType(), 0.0), "is_zero");
} else {
IsZero = Builder.CreateICmpEQ(Divisor, ConstantInt::get(Divisor->getType(), 0), "is_zero");
}
emitCheck(IsZero, DivZeroMsg, Line);
}
void RuntimeCheck::emitIndexCheck(Value *Index, Value *Lower, Value *Upper, int Line) {
Value *TooLow = Builder.CreateICmpSLT(Index, Lower, "too_low");
Value *TooHigh = Builder.CreateICmpSGT(Index, Upper, "too_high");
Value *OutOfBounds = Builder.CreateOr(TooLow, TooHigh, "out_of_bounds");
emitCheck(OutOfBounds, OutOfBoundsMsg, Line);
}
void RuntimeCheck::emitEnumRangeCheck(Value *Ordinal, uint64_t ValueCount,
const std::string &TypeName, int Line) {
Value *Lo = ConstantInt::get(TheContext, APInt(64, static_cast<uint64_t>(kEnumOrdinalBase), true));
Value *Hi = ConstantInt::get(TheContext,
APInt(64, static_cast<uint64_t>(kEnumOrdinalBase) + ValueCount, true));
Value *TooLow = Builder.CreateICmpSLT(Ordinal, Lo, "enum_too_low");
Value *TooHigh = Builder.CreateICmpSGE(Ordinal, Hi, "enum_too_high");
Value *OutOfRange = Builder.CreateOr(TooLow, TooHigh, "enum_out_of_range");
Value *NameStr = Builder.CreateGlobalString(TypeName, "enum_name", 0, &TheModule);
emitCheck(OutOfRange, EnumRangeMsg,
{ConstantInt::get(TheContext, APInt(32, Line)), NameStr});
}
void RuntimeCheck::emitNullDerefCheck(Value *Ptr, int Line) {
Value *IsNull = Builder.CreateICmpEQ(Ptr,
ConstantPointerNull::get(PointerType::getUnqual(TheContext)),
"ptr_is_null");
emitCheck(IsNull, NullDerefMsg, Line);
}
void RuntimeCheck::emitArrayArgBoundsCheck(Value *ActualLower, Value *ActualUpper,
int64_t DeclaredLower, int64_t DeclaredUpper,
int Line) {
Value *DeclLo = ConstantInt::get(TheContext, APInt(64, static_cast<uint64_t>(DeclaredLower), true));
Value *DeclHi = ConstantInt::get(TheContext, APInt(64, static_cast<uint64_t>(DeclaredUpper), true));
Value *LoDiff = Builder.CreateICmpNE(ActualLower, DeclLo, "arg_lo_ne");
Value *HiDiff = Builder.CreateICmpNE(ActualUpper, DeclHi, "arg_hi_ne");
Value *Mismatch = Builder.CreateOr(LoDiff, HiDiff, "arg_bounds_ne");
emitCheck(Mismatch, ArrayArgBoundsMsg,
{ConstantInt::get(TheContext, APInt(32, Line)),
ActualLower, ActualUpper, DeclLo, DeclHi});
}
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