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fix(qbe): use extraData instead of child3 for hIf else-branch

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Block lowering overwrites child3 for statement chaining.
Else block is stored in extraData by hir_lower (matches c_backend).
Fixes QBE parse error 'last block misses jump' in if-without-else chains.
This commit is contained in:
dimgigov
2026-06-02 18:07:35 +03:00
parent eb8179b6d0
commit ec4e748584
10 changed files with 756 additions and 72 deletions
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src_bux/qbe_backend.bux
+117 -21
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@@ -66,12 +66,16 @@ struct QbeEmitter {
// Const table for inline substitution
constCount: int;
consts: *HirConst;
// Current function for param type lookup
currentFunc: *HirFunc;
// Module reference for function return type lookup
mod: *HirModule;
}
func QBE_Init() -> QbeEmitter {
var dsb: StringBuilder = StringBuilder_NewCap(4096);
var csb: StringBuilder = StringBuilder_NewCap(16384);
return QbeEmitter { dataSb: dsb, codeSb: csb, tempId: 0, labelId: 0, strId: 0, indent: 0, inBlock: false, constCount: 0, consts: null as *HirConst };
return QbeEmitter { dataSb: dsb, codeSb: csb, tempId: 0, labelId: 0, strId: 0, indent: 0, inBlock: false, constCount: 0, consts: null as *HirConst, currentFunc: null as *HirFunc, mod: null as *HirModule };
}
func QBE_FreshTemp(qbe: *QbeEmitter) -> String {
@@ -262,8 +266,8 @@ func QBE_IsTerminator(node: *HirNode) -> bool {
if node.kind == hBreak { return true; }
if node.kind == hContinue { return true; }
if node.kind == hIf {
if node.child3 != null as *HirNode {
return QBE_IsTerminator(node.child2) && QBE_IsTerminator(node.child3);
if node.extraData != null as *HirNode {
return QBE_IsTerminator(node.child2) && QBE_IsTerminator(node.extraData as *HirNode);
}
return false;
}
@@ -280,6 +284,56 @@ func QBE_IsTerminator(node: *HirNode) -> bool {
return false;
}
// ---------------------------------------------------------------------------
// Helper: find function by name in module
// ---------------------------------------------------------------------------
func QBE_FindFunc(qbe: *QbeEmitter, name: String) -> *HirFunc {
if qbe.mod == null as *HirModule { return null as *HirFunc; }
var i: int = 0;
while i < qbe.mod.funcCount {
if String_Eq(qbe.mod.funcs[i].name, name) {
return &qbe.mod.funcs[i];
}
i = i + 1;
}
i = 0;
while i < qbe.mod.externCount {
if String_Eq(qbe.mod.externFuncs[i].name, name) {
return &qbe.mod.externFuncs[i];
}
i = i + 1;
}
return null as *HirFunc;
}
// ---------------------------------------------------------------------------
// Helper: determine QBE type for any HIR node
// ---------------------------------------------------------------------------
func QBE_NodeType(qbe: *QbeEmitter, node: *HirNode) -> String {
if node == null as *HirNode { return "l"; }
// For variables, check param type first
if node.kind == hVar && qbe.currentFunc != null as *HirFunc {
var pi2: int = 0;
var pnames2: *HirParam = &qbe.currentFunc.param0;
while pi2 < qbe.currentFunc.paramCount {
if String_Eq(pnames2[pi2].name, node.strValue) {
return QbeBackend_TypeWord(pnames2[pi2].typeKind);
}
pi2 = pi2 + 1;
}
}
// For calls, look up callee return type
if node.kind == hCall && qbe.mod != null as *HirModule {
let callee: *HirFunc = QBE_FindFunc(qbe, node.strValue);
if callee != null as *HirFunc {
return QbeBackend_TypeWord(callee.retTypeKind);
}
}
return QbeBackend_TypeWord(node.typeKind);
}
// ---------------------------------------------------------------------------
// Expression emission — returns the QBE value string (e.g. "%t3", "42", "$foo")
// For expressions that need multiple instructions, emits them inline.
@@ -325,8 +379,21 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
return "0";
}
}
// Determine type: use param type if available, else node.typeKind
var varTy: int = node.typeKind;
if qbe.currentFunc != null as *HirFunc {
var pi2: int = 0;
var pnames2: *HirParam = &qbe.currentFunc.param0;
while pi2 < qbe.currentFunc.paramCount {
if String_Eq(pnames2[pi2].name, node.strValue) {
varTy = pnames2[pi2].typeKind;
break;
}
pi2 = pi2 + 1;
}
}
let tmp: String = QBE_FreshTemp(qbe);
let ty: String = QbeBackend_TypeWord(node.typeKind);
let ty: String = QbeBackend_TypeWord(varTy);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, tmp);
QBE_Emit(qbe, " =");
@@ -350,7 +417,7 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
}
let val: String = QBE_EmitExpr(qbe, node.child2);
if String_Eq(val, "") { val = "0"; }
let ty: String = QbeBackend_TypeWord(node.typeKind);
let ty: String = QBE_NodeType(qbe, node.child2);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, "store");
QBE_Emit(qbe, ty);
@@ -366,12 +433,12 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
let op: int = node.intValue;
let left: String = QBE_EmitExpr(qbe, node.child1);
let right: String = QBE_EmitExpr(qbe, node.child2);
let ty: String = QbeBackend_TypeWord(node.typeKind);
let ty: String = QBE_NodeType(qbe, node.child1);
// Comparison operators
// QBE comparison ops: ceqw/ceql, cnew/cnel, csltw/csltl, cslew/cslel, csgtw/csgtl, csgew/csgel
var cmpOp: String = "";
var cmpTy: String = ty;
let cmpTy: String = QBE_NodeType(qbe, node.child1);
if op == tkEq { cmpOp = "ceq"; }
else if op == tkNe { cmpOp = "cne"; }
else if op == tkLt { cmpOp = "cslt"; }
@@ -385,7 +452,7 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
QBE_Emit(qbe, cmpTmp);
QBE_Emit(qbe, " =w ");
QBE_Emit(qbe, cmpOp);
QBE_Emit(qbe, ty);
QBE_Emit(qbe, cmpTy);
QBE_Emit(qbe, " ");
QBE_Emit(qbe, QBE_EnsureLocal(left));
QBE_Emit(qbe, ", ");
@@ -452,7 +519,7 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
let rVal: String = QBE_EmitExpr(qbe, node.child2);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, tmp);
QBE_Emit(qbe, " =l copy ");
QBE_Emit(qbe, " =w copy ");
QBE_EmitLine(qbe, rVal);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, "jmp ");
@@ -460,7 +527,7 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
QBE_EmitLine(qbe, lFalse);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, tmp);
QBE_EmitLine(qbe, " =l copy 0");
QBE_EmitLine(qbe, " =w copy 0");
QBE_EmitLine(qbe, lEnd);
return tmp;
}
@@ -479,7 +546,7 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
QBE_EmitLine(qbe, lTrue);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, tmp);
QBE_EmitLine(qbe, " =l copy 1");
QBE_EmitLine(qbe, " =w copy 1");
QBE_EmitIndent(qbe);
QBE_Emit(qbe, "jmp ");
QBE_EmitLine(qbe, lEnd);
@@ -487,7 +554,7 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
let rVal: String = QBE_EmitExpr(qbe, node.child2);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, tmp);
QBE_Emit(qbe, " =l copy ");
QBE_Emit(qbe, " =w copy ");
QBE_EmitLine(qbe, rVal);
QBE_EmitLine(qbe, lEnd);
return tmp;
@@ -500,7 +567,7 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
if kind == hUnary {
let op: int = node.intValue;
let operand: String = QBE_EmitExpr(qbe, node.child1);
let ty: String = QbeBackend_TypeWord(node.typeKind);
let ty: String = QBE_NodeType(qbe, node.child1);
if op == tkBang || op == tkMinus {
let tmp: String = QBE_FreshTemp(qbe);
@@ -535,7 +602,14 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
if kind == hCall {
// Pre-evaluate arguments to avoid emitting instructions inside the call
let tmp: String = QBE_FreshTemp(qbe);
let retTy: String = QbeBackend_TypeWord(node.typeKind);
var retTy: String = QbeBackend_TypeWord(node.typeKind);
// Look up callee return type from module if typeKind is unknown
if String_Eq(retTy, "l") && qbe.mod != null as *HirModule {
let callee: *HirFunc = QBE_FindFunc(qbe, node.strValue);
if callee != null as *HirFunc {
retTy = QbeBackend_TypeWord(callee.retTypeKind);
}
}
var arg1: String = "";
var arg2: String = "";
if node.child1 != null as *HirNode {
@@ -552,13 +626,13 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
QBE_Emit(qbe, QBE_EscapeIdent(node.strValue));
QBE_Emit(qbe, "(");
if node.child1 != null as *HirNode {
let a1ty: String = QbeBackend_TypeWord(node.child1.typeKind);
let a1ty: String = QBE_NodeType(qbe, node.child1);
QBE_Emit(qbe, a1ty);
QBE_Emit(qbe, " ");
QBE_Emit(qbe, QBE_EnsureLocal(arg1));
}
if node.child2 != null as *HirNode {
let a2ty: String = QbeBackend_TypeWord(node.child2.typeKind);
let a2ty: String = QBE_NodeType(qbe, node.child2);
QBE_Emit(qbe, ", ");
QBE_Emit(qbe, a2ty);
QBE_Emit(qbe, " ");
@@ -599,6 +673,20 @@ func QBE_EmitExpr(qbe: *QbeEmitter, node: *HirNode) -> String {
return tmp;
}
// Index pointer: &arr[idx] (for pointer indexing)
if kind == hIndexPtr {
let base: String = QBE_EmitExpr(qbe, node.child1);
let idx: String = QBE_EmitExpr(qbe, node.child2);
let tmp: String = QBE_FreshTemp(qbe);
QBE_EmitIndent(qbe);
QBE_Emit(qbe, tmp);
QBE_Emit(qbe, " =l add ");
QBE_Emit(qbe, QBE_EnsureLocal(base));
QBE_Emit(qbe, ", ");
QBE_EmitLine(qbe, QBE_EnsureLocal(idx));
return tmp;
}
// Cast — QBE doesn't need same-width casts; passthrough
if kind == hCast {
return QBE_EmitExpr(qbe, node.child1);
@@ -626,6 +714,12 @@ func QBE_EmitStmt(qbe: *QbeEmitter, node: *HirNode) {
if node == null as *HirNode { return; }
let kind: int = node.kind;
// Assign statement
if kind == hAssign {
discard QBE_EmitExpr(qbe, node);
return;
}
// Store: declaration or assignment
if kind == hStore {
if node.child1 != null as *HirNode && node.child1.kind == hAlloca {
@@ -653,7 +747,7 @@ func QBE_EmitStmt(qbe: *QbeEmitter, node: *HirNode) {
// Plain assignment
let target: String = QBE_EmitExpr(qbe, node.child1);
let val: String = QBE_EmitExpr(qbe, node.child2);
let ty: String = QbeBackend_TypeWord(node.typeKind);
let ty: String = QBE_NodeType(qbe, node.child2);
if String_Eq(val, "") { val = "0"; }
if String_Eq(target, "") { return; }
QBE_EmitIndent(qbe);
@@ -692,7 +786,7 @@ func QBE_EmitStmt(qbe: *QbeEmitter, node: *HirNode) {
QBE_Emit(qbe, ", ");
QBE_Emit(qbe, lThen);
QBE_Emit(qbe, ", ");
var hasElse: bool = node.child3 != null as *HirNode;
var hasElse: bool = node.extraData != null as *HirNode;
if hasElse {
QBE_EmitLine(qbe, lElse);
} else {
@@ -709,8 +803,8 @@ func QBE_EmitStmt(qbe: *QbeEmitter, node: *HirNode) {
if hasElse {
QBE_EmitLine(qbe, lElse);
QBE_EmitStmt(qbe, node.child3);
if !QBE_IsTerminator(node.child3) {
QBE_EmitStmt(qbe, node.extraData as *HirNode);
if !QBE_IsTerminator(node.extraData as *HirNode) {
QBE_EmitIndent(qbe);
QBE_Emit(qbe, "jmp ");
QBE_EmitLine(qbe, lEnd);
@@ -719,7 +813,7 @@ func QBE_EmitStmt(qbe: *QbeEmitter, node: *HirNode) {
// Only emit @lEnd if at least one branch falls through
var needEnd: bool = !QBE_IsTerminator(node.child2);
if hasElse && !QBE_IsTerminator(node.child3) {
if hasElse && !QBE_IsTerminator(node.extraData as *HirNode) {
needEnd = true;
}
if needEnd {
@@ -828,6 +922,7 @@ func QBE_EmitStmt(qbe: *QbeEmitter, node: *HirNode) {
func QBE_EmitFunc(qbe: *QbeEmitter, f: *HirFunc) {
if f.body == null as *HirNode { return; }
qbe.currentFunc = f;
QBE_Emit(qbe, "export function ");
let retTy: String = QbeBackend_TypeWord(f.retTypeKind);
@@ -929,6 +1024,7 @@ func QbeBackend_Generate(mod: *HirModule) -> String {
qbe.inBlock = false;
qbe.constCount = mod.constCount;
qbe.consts = mod.consts;
qbe.mod = mod;
// Header
QBE_EmitLine(qbe, "# Generated by Bux QBE Backend");