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xo-jit: + codegen for if-expressions

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This commit is contained in:
Roland Conybeare 2024-06-17 12:29:15 -04:00
commit 32c7451191
2 changed files with 85 additions and 2 deletions
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82
src/jit/MachPipeline.cpp
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@ -10,6 +10,7 @@ namespace xo {
using xo::ast::Lambda;
using xo::ast::Variable;
using xo::ast::Apply;
using xo::ast::IfExpr;
using xo::reflect::TypeDescr;
using std::cerr;
using std::endl;
@ -370,6 +371,85 @@ namespace xo {
return ix->second;
} /*codegen_variable*/
llvm::Value *
MachPipeline::codegen_ifexpr(ref::brw<IfExpr> expr)
{
llvm::Value * test_ir = this->codegen(expr->test());
/** need test result in a variable
**/
llvm::Value * test_with_cmp_ir
= llvm_ir_builder_->CreateFCmpONE(test_ir,
llvm::ConstantFP::get(llvm_cx_->llvm_cx_ref(),
llvm::APFloat(0.0)),
"iftest");
llvm::Function * parent_fn = llvm_ir_builder_->GetInsertBlock()->getParent();
/* when_true_bb, when_false_bb, merge_bb:
* initially-empty basic-blocks for {when_true, when_false, merged} codegen
*/
/* when_true branch inserted at (current) end of function */
llvm::BasicBlock * when_true_bb
= llvm::BasicBlock::Create(llvm_cx_->llvm_cx_ref(),
"when_true",
parent_fn);
llvm::BasicBlock * when_false_bb
= llvm::BasicBlock::Create(llvm_cx_->llvm_cx_ref(),
"when_false");
llvm::BasicBlock * merge_bb
= llvm::BasicBlock::Create(llvm_cx_->llvm_cx_ref(),
"merge");
/* IR to direct control flow to one of {when_true_bb, when_false_bb},
* depending on result of test_with_cmp_ir
*/
llvm_ir_builder_->CreateCondBr(test_with_cmp_ir,
when_true_bb,
when_false_bb);
/* populate when_true_bb */
llvm_ir_builder_->SetInsertPoint(when_true_bb);
llvm::Value * when_true_ir = this->codegen(expr->when_true());
if (!when_true_ir)
return nullptr;
/* at end of when-true sequence, jump to merge suffix */
llvm_ir_builder_->CreateBr(merge_bb);
/* note: codegen for expr->when_true() may have altered builder's "current block" */
when_true_bb = llvm_ir_builder_->GetInsertBlock();
/* populate when_false_bb */
parent_fn->insert(parent_fn->end(), when_false_bb);
llvm_ir_builder_->SetInsertPoint(when_false_bb);
llvm::Value * when_false_ir = this->codegen(expr->when_false());
if (!when_false_ir)
return nullptr;
/* at end of when-false sequence, jump to merge suffix */
llvm_ir_builder_->CreateBr(merge_bb);
/* note: codegen for expr->when_false() may have altered builder's "current block" */
when_false_bb = llvm_ir_builder_->GetInsertBlock();
/* merged suffix sequence */
parent_fn->insert(parent_fn->end(), merge_bb);
llvm_ir_builder_->SetInsertPoint(merge_bb);
llvm::PHINode * phi_node
= llvm_ir_builder_->CreatePHI(llvm::Type::getDoubleTy(llvm_cx_->llvm_cx_ref()),
2 /*#of branches being merged (?)*/,
"iftmp");
phi_node->addIncoming(when_true_ir, when_true_bb);
phi_node->addIncoming(when_false_ir, when_false_bb);
return phi_node;
}
llvm::Value *
MachPipeline::codegen(ref::brw<Expression> expr)
{
@ -384,6 +464,8 @@ namespace xo {
return this->codegen_lambda(Lambda::from(expr));
case exprtype::variable:
return this->codegen_variable(Variable::from(expr));
case exprtype::if_expr:
return this->codegen_ifexpr(IfExpr::from(expr));
case exprtype::invalid:
case exprtype::n_expr:
return nullptr;