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astgen: add shift assignment operators and grouped_expression unwrapping

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Port assignShift (AstGen.zig:3786) and assignShiftSat (AstGen.zig:3812)
from upstream, handling <<=, >>=, and <<|= operators as both statements
in blockExprStmts and expressions in exprRl. Previously these fell
through to SET_ERROR.

Add grouped_expression unwrapping loop in blockExprStmts (matching
AstGen.zig:2569-2630) so that parenthesized statements like `(x += 1)`
are correctly dispatched to assignment handlers instead of going through
the default unusedResultExpr path.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Motiejus Jakštys
2026-02-13 22:23:04 +00:00
parent f54d3f94a3
commit 2fc7e81d49
1 changed files with 225 additions and 133 deletions
Download Patch File Download Diff File Expand all files Collapse all files

140
astgen.c
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@@ -2185,6 +2185,9 @@ static uint32_t exprRl(GenZir* gz, Scope* scope, ResultLoc rl, uint32_t node);
static void assignStmt(GenZir* gz, Scope* scope, uint32_t infix_node);
static void assignOp(
GenZir* gz, Scope* scope, uint32_t infix_node, ZirInstTag op_tag);
static void assignShift(
GenZir* gz, Scope* scope, uint32_t infix_node, ZirInstTag op_tag);
static void assignShiftSat(GenZir* gz, Scope* scope, uint32_t infix_node);
static uint32_t shiftOp(
GenZir* gz, Scope* scope, uint32_t node, ZirInstTag tag);
static void emitDbgStmt(GenZir* gz, uint32_t line, uint32_t column);
@@ -4799,6 +4802,16 @@ static uint32_t exprRl(GenZir* gz, Scope* scope, ResultLoc rl, uint32_t node) {
case AST_NODE_ASSIGN_MUL_SAT:
assignOp(gz, scope, node, ZIR_INST_MUL_SAT);
return ZIR_REF_VOID_VALUE;
// Shift assignment operators (AstGen.zig:676-687).
case AST_NODE_ASSIGN_SHL:
assignShift(gz, scope, node, ZIR_INST_SHL);
return ZIR_REF_VOID_VALUE;
case AST_NODE_ASSIGN_SHR:
assignShift(gz, scope, node, ZIR_INST_SHR);
return ZIR_REF_VOID_VALUE;
case AST_NODE_ASSIGN_SHL_SAT:
assignShiftSat(gz, scope, node);
return ZIR_REF_VOID_VALUE;
default:
SET_ERROR(ag);
return ZIR_REF_VOID_VALUE;
@@ -6264,6 +6277,63 @@ static void assignOp(
addPlNodeBin(gz, ZIR_INST_STORE_NODE, infix_node, lhs_ptr, result);
}
// --- assignShift (AstGen.zig:3786) ---
// Handles <<= and >>= assignment operators.
static void assignShift(
GenZir* gz, Scope* scope, uint32_t infix_node, ZirInstTag op_tag) {
emitDbgNode(gz, infix_node);
const AstGenCtx* ag = gz->astgen;
const Ast* tree = ag->tree;
AstData nd = tree->nodes.datas[infix_node];
uint32_t lhs_node = nd.lhs;
uint32_t rhs_node = nd.rhs;
// Evaluate LHS as lvalue pointer (AstGen.zig:3797).
uint32_t lhs_ptr = exprRl(gz, scope, RL_REF_VAL, lhs_node);
// Load current value (AstGen.zig:3798).
uint32_t lhs = addUnNode(gz, ZIR_INST_LOAD, lhs_ptr, infix_node);
// RHS type is typeof_log2_int_type of LHS (AstGen.zig:3799).
uint32_t rhs_type
= addUnNode(gz, ZIR_INST_TYPEOF_LOG2_INT_TYPE, lhs, infix_node);
ResultLoc rhs_rl = {
.tag = RL_TY, .data = rhs_type, .src_node = 0, .ctx = RI_CTX_NONE
};
uint32_t rhs = exprRl(gz, scope, rhs_rl, rhs_node);
// Emit the shift operation (AstGen.zig:3802-3805).
uint32_t result = addPlNodeBin(gz, op_tag, infix_node, lhs, rhs);
// Store result back (AstGen.zig:3806-3809).
addPlNodeBin(gz, ZIR_INST_STORE_NODE, infix_node, lhs_ptr, result);
}
// --- assignShiftSat (AstGen.zig:3812) ---
// Handles <<|= saturating shift-left assignment.
static void assignShiftSat(GenZir* gz, Scope* scope, uint32_t infix_node) {
emitDbgNode(gz, infix_node);
const AstGenCtx* ag = gz->astgen;
const Ast* tree = ag->tree;
AstData nd = tree->nodes.datas[infix_node];
uint32_t lhs_node = nd.lhs;
uint32_t rhs_node = nd.rhs;
// Evaluate LHS as lvalue pointer (AstGen.zig:3818).
uint32_t lhs_ptr = exprRl(gz, scope, RL_REF_VAL, lhs_node);
// Load current value (AstGen.zig:3819).
uint32_t lhs = addUnNode(gz, ZIR_INST_LOAD, lhs_ptr, infix_node);
// Saturating shift-left allows any integer type for both LHS and RHS
// (AstGen.zig:3820-3821).
uint32_t rhs = expr(gz, scope, rhs_node);
// Emit shl_sat (AstGen.zig:3823-3825).
uint32_t result = addPlNodeBin(gz, ZIR_INST_SHL_SAT, infix_node, lhs, rhs);
// Store result back (AstGen.zig:3827-3830).
addPlNodeBin(gz, ZIR_INST_STORE_NODE, infix_node, lhs_ptr, result);
}
// --- builtinEvalToError (BuiltinFn.zig) ---
// Returns per-builtin eval_to_error. Default is .never; only a few are
// .maybe or .always. Mirrors BuiltinFn.list lookup in AstGen.zig:10539.
@@ -6911,53 +6981,68 @@ static void blockExprStmts(GenZir* gz, Scope* scope,
if (ag->has_compile_errors)
return;
uint32_t stmt = statements[i];
AstNodeTag tag = ag->tree->nodes.tags[stmt];
// Unwrap grouped_expression (parentheses) before dispatching
// (AstGen.zig:2569-2630).
uint32_t inner_node = stmt;
for (;;) {
AstNodeTag tag = ag->tree->nodes.tags[inner_node];
switch (tag) {
case AST_NODE_ASSIGN:
assignStmt(gz, cur_scope, stmt);
assignStmt(gz, cur_scope, inner_node);
break;
// Shift assignment operators (AstGen.zig:2585-2586).
case AST_NODE_ASSIGN_SHL:
assignShift(gz, cur_scope, inner_node, ZIR_INST_SHL);
break;
case AST_NODE_ASSIGN_SHR:
assignShift(gz, cur_scope, inner_node, ZIR_INST_SHR);
break;
// Saturating shift-left assignment (AstGen.zig:680-682 via expr).
case AST_NODE_ASSIGN_SHL_SAT:
assignShiftSat(gz, cur_scope, inner_node);
break;
// Compound assignment operators (AstGen.zig:2588-2607).
case AST_NODE_ASSIGN_ADD:
assignOp(gz, cur_scope, stmt, ZIR_INST_ADD);
assignOp(gz, cur_scope, inner_node, ZIR_INST_ADD);
break;
case AST_NODE_ASSIGN_SUB:
assignOp(gz, cur_scope, stmt, ZIR_INST_SUB);
assignOp(gz, cur_scope, inner_node, ZIR_INST_SUB);
break;
case AST_NODE_ASSIGN_MUL:
assignOp(gz, cur_scope, stmt, ZIR_INST_MUL);
assignOp(gz, cur_scope, inner_node, ZIR_INST_MUL);
break;
case AST_NODE_ASSIGN_DIV:
assignOp(gz, cur_scope, stmt, ZIR_INST_DIV);
assignOp(gz, cur_scope, inner_node, ZIR_INST_DIV);
break;
case AST_NODE_ASSIGN_MOD:
assignOp(gz, cur_scope, stmt, ZIR_INST_MOD_REM);
assignOp(gz, cur_scope, inner_node, ZIR_INST_MOD_REM);
break;
case AST_NODE_ASSIGN_BIT_AND:
assignOp(gz, cur_scope, stmt, ZIR_INST_BIT_AND);
assignOp(gz, cur_scope, inner_node, ZIR_INST_BIT_AND);
break;
case AST_NODE_ASSIGN_BIT_OR:
assignOp(gz, cur_scope, stmt, ZIR_INST_BIT_OR);
assignOp(gz, cur_scope, inner_node, ZIR_INST_BIT_OR);
break;
case AST_NODE_ASSIGN_BIT_XOR:
assignOp(gz, cur_scope, stmt, ZIR_INST_XOR);
assignOp(gz, cur_scope, inner_node, ZIR_INST_XOR);
break;
case AST_NODE_ASSIGN_ADD_WRAP:
assignOp(gz, cur_scope, stmt, ZIR_INST_ADDWRAP);
assignOp(gz, cur_scope, inner_node, ZIR_INST_ADDWRAP);
break;
case AST_NODE_ASSIGN_SUB_WRAP:
assignOp(gz, cur_scope, stmt, ZIR_INST_SUBWRAP);
assignOp(gz, cur_scope, inner_node, ZIR_INST_SUBWRAP);
break;
case AST_NODE_ASSIGN_MUL_WRAP:
assignOp(gz, cur_scope, stmt, ZIR_INST_MULWRAP);
assignOp(gz, cur_scope, inner_node, ZIR_INST_MULWRAP);
break;
case AST_NODE_ASSIGN_ADD_SAT:
assignOp(gz, cur_scope, stmt, ZIR_INST_ADD_SAT);
assignOp(gz, cur_scope, inner_node, ZIR_INST_ADD_SAT);
break;
case AST_NODE_ASSIGN_SUB_SAT:
assignOp(gz, cur_scope, stmt, ZIR_INST_SUB_SAT);
assignOp(gz, cur_scope, inner_node, ZIR_INST_SUB_SAT);
break;
case AST_NODE_ASSIGN_MUL_SAT:
assignOp(gz, cur_scope, stmt, ZIR_INST_MUL_SAT);
assignOp(gz, cur_scope, inner_node, ZIR_INST_MUL_SAT);
break;
case AST_NODE_SIMPLE_VAR_DECL:
case AST_NODE_LOCAL_VAR_DECL:
@@ -6982,7 +7067,8 @@ static void blockExprStmts(GenZir* gz, Scope* scope,
SET_ERROR(ag);
break;
}
ScopeTag scope_tag = (tag == AST_NODE_DEFER) ? SCOPE_DEFER_NORMAL
ScopeTag scope_tag = (tag == AST_NODE_DEFER)
? SCOPE_DEFER_NORMAL
: SCOPE_DEFER_ERROR;
// Create sub-block for defer body (AstGen.zig:3123-3126).
GenZir defer_gen = makeSubBlock(gz, cur_scope);
@@ -7004,8 +7090,8 @@ static void blockExprStmts(GenZir* gz, Scope* scope,
addEnsureResult(&defer_gen, defer_result, expr_node);
// Add break_inline at end (AstGen.zig:3167).
addBreak(&defer_gen, ZIR_INST_BREAK_INLINE, 0, ZIR_REF_VOID_VALUE,
AST_NODE_OFFSET_NONE);
addBreak(&defer_gen, ZIR_INST_BREAK_INLINE, 0,
ZIR_REF_VOID_VALUE, AST_NODE_OFFSET_NONE);
// Write body to extra (AstGen.zig:3173-3175).
uint32_t raw_body_len = gzInstructionsLen(&defer_gen);
@@ -7029,25 +7115,31 @@ static void blockExprStmts(GenZir* gz, Scope* scope,
defer_idx++;
break;
}
// Grouped expression: unwrap parentheses (AstGen.zig:2600-2602).
case AST_NODE_GROUPED_EXPRESSION:
inner_node = ag->tree->nodes.datas[inner_node].lhs;
continue;
// while/for as statements (AstGen.zig:2605-2610).
// These do NOT get emitDbgNode; they emit their own dbg_stmt.
case AST_NODE_WHILE_SIMPLE:
case AST_NODE_WHILE_CONT:
case AST_NODE_WHILE:
(void)whileExpr(gz, cur_scope, stmt, true);
(void)whileExpr(gz, cur_scope, inner_node, true);
break;
case AST_NODE_FOR_SIMPLE:
case AST_NODE_FOR:
(void)forExpr(gz, cur_scope, stmt, true);
(void)forExpr(gz, cur_scope, inner_node, true);
break;
default: {
// Expression statement (AstGen.zig:2627 unusedResultExpr).
emitDbgNode(gz, stmt);
uint32_t result = expr(gz, cur_scope, stmt);
noreturn_stmt = addEnsureResult(gz, result, stmt);
emitDbgNode(gz, inner_node);
uint32_t result = expr(gz, cur_scope, inner_node);
noreturn_stmt = addEnsureResult(gz, result, inner_node);
break;
}
}
break; // Break out of the for(;;) unwrapping loop.
}
}
// Emit normal defers at block exit (AstGen.zig:2633-2634).
if (!noreturn_stmt) {