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stage2: add support for loops in LLVM backend

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A simple `while(true) {}` loop generates the following LLVMIR:
```
define i32 @main() {
Entry:
  br label %Loop

Loop:                                 ; preds = %Loop, %Entry
  br label %Loop
}
```

Also implement TZIR printing for loops and add a corresponding test.
This commit is contained in:
Timon Kruiper
2021-01-10 17:36:01 +01:00
committed by Andrew Kelley
parent 2117489e05
commit e1d8073d2f
3 changed files with 52 additions and 2 deletions
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12
src/codegen/llvm.zig
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@@ -396,6 +396,7 @@ pub const LLVMIRModule = struct {
.condbr => try self.genCondBr(inst.castTag(.condbr).?),
.intcast => try self.genIntCast(inst.castTag(.intcast).?),
.load => try self.genLoad(inst.castTag(.load).?),
.loop => try self.genLoop(inst.castTag(.loop).?),
.not => try self.genNot(inst.castTag(.not).?),
.ret => try self.genRet(inst.castTag(.ret).?),
.retvoid => self.genRetVoid(inst.castTag(.retvoid).?),
@@ -559,6 +560,17 @@ pub const LLVMIRModule = struct {
return null;
}
fn genLoop(self: *LLVMIRModule, inst: *Inst.Loop) !?*const llvm.Value {
const loop_block = self.context.appendBasicBlock(self.llvm_func, "Loop");
_ = self.builder.buildBr(loop_block);
self.builder.positionBuilderAtEnd(loop_block);
try self.genBody(inst.body);
_ = self.builder.buildBr(loop_block);
return null;
}
fn genNot(self: *LLVMIRModule, inst: *Inst.UnOp) !?*const llvm.Value {
return self.builder.buildNot(try self.resolveInst(inst.operand), "");
}