From 31be1ddf09fafae270d9946a3f09aa25816dd153 Mon Sep 17 00:00:00 2001 From: Andrew Kelley Date: Sat, 9 Feb 2019 20:57:45 -0500 Subject: docs: add threadlocal keyword to grammar --- doc/langref.html.in | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'doc/langref.html.in') diff --git a/doc/langref.html.in b/doc/langref.html.in index 2cd35c2f4e..dfea8e1e04 100644 --- a/doc/langref.html.in +++ b/doc/langref.html.in @@ -7870,7 +7870,7 @@ TopLevelComptime <- KEYWORD_comptime BlockExpr TopLevelDecl <- (KEYWORD_export / KEYWORD_extern STRINGLITERAL? / KEYWORD_inline)? FnProto (SEMICOLON / Block) - / (KEYWORD_export / KEYWORD_extern STRINGLITERAL?)? VarDecl + / (KEYWORD_export / KEYWORD_extern STRINGLITERAL?)? KEYWORD_threadlocal? VarDecl / KEYWORD_use Expr SEMICOLON FnProto <- FnCC? KEYWORD_fn IDENTIFIER? LPAREN ParamDeclList RPAREN ByteAlign? LinkSection? EXCLAMATIONMARK? (KEYWORD_var / TypeExpr) @@ -8330,6 +8330,7 @@ KEYWORD_struct <- 'struct' end_of_word KEYWORD_suspend <- 'suspend' end_of_word KEYWORD_switch <- 'switch' end_of_word KEYWORD_test <- 'test' end_of_word +KEYWORD_threadlocal <- 'threadlocal' end_of_word KEYWORD_true <- 'true' end_of_word KEYWORD_try <- 'try' end_of_word KEYWORD_undefined <- 'undefined' end_of_word @@ -8350,7 +8351,7 @@ keyword <- KEYWORD_align / KEYWORD_and / KEYWORD_anyerror / KEYWORD_asm / KEYWORD_orelse / KEYWORD_packed / KEYWORD_promise / KEYWORD_pub / KEYWORD_resume / KEYWORD_return / KEYWORD_linksection / KEYWORD_stdcallcc / KEYWORD_struct / KEYWORD_suspend - / KEYWORD_switch / KEYWORD_test / KEYWORD_true / KEYWORD_try + / KEYWORD_switch / KEYWORD_test / KEYWORD_threadlocal / KEYWORD_true / KEYWORD_try / KEYWORD_undefined / KEYWORD_union / KEYWORD_unreachable / KEYWORD_use / KEYWORD_var / KEYWORD_volatile / KEYWORD_while {#header_close#} -- cgit v1.2.3 From caf672c49586f1af5e3d41ae200aded991b8b0f7 Mon Sep 17 00:00:00 2001 From: Andrew Kelley Date: Sat, 9 Feb 2019 21:10:59 -0500 Subject: `@truncate`: comptime 0 when target type is 0 bits also if the dest type is a comptime_int, then treat it as an implicit cast. also compile error for attempting to truncate undefined closes #1568 --- doc/langref.html.in | 11 +++++++---- src/ir.cpp | 24 ++++++++++++++++-------- test/compile_errors.zig | 11 ++++++++++- test/stage1/behavior/truncate.zig | 23 +++++++++++++++++++++++ 4 files changed, 56 insertions(+), 13 deletions(-) (limited to 'doc/langref.html.in') diff --git a/doc/langref.html.in b/doc/langref.html.in index dfea8e1e04..779eb6a31b 100644 --- a/doc/langref.html.in +++ b/doc/langref.html.in @@ -6381,14 +6381,14 @@ fn List(comptime T: type) type { {#header_close#} {#header_open|@truncate#} - 
{#syntax#}@truncate(comptime T: type, integer) T{#endsyntax#}
+ 
{#syntax#}@truncate(comptime T: type, integer: var) T{#endsyntax#}

This function truncates bits from an integer type, resulting in a smaller integer type.

- The following produces a crash in debug mode and undefined behavior in - release mode: + The following produces a crash in {#link|Debug#} mode and {#link|Undefined Behavior#} in + {#link|ReleaseFast#} mode: 

{#syntax#}const a: u16 = 0xabcd;
 const b: u8 = u8(a);{#endsyntax#}
@@ -6402,7 +6402,10 @@ const b: u8 = @truncate(u8, a); This function always truncates the significant bits of the integer, regardless of endianness on the target platform.

- +

+ If {#syntax#}T{#endsyntax#} is {#syntax#}comptime_int{#endsyntax#}, + then this is semantically equivalent to an {#link|implicit cast|Implicit Casts#}. +

{#header_close#} {#header_open|@typeId#} diff --git a/src/ir.cpp b/src/ir.cpp index d87486bbdd..5d4013b4b9 100644 --- a/src/ir.cpp +++ b/src/ir.cpp @@ -18491,7 +18491,22 @@ static IrInstruction *ir_analyze_instruction_truncate(IrAnalyze *ira, IrInstruct return ira->codegen->invalid_instruction; } - if (src_type->data.integral.bit_count == 0) { + if (dest_type->id == ZigTypeIdComptimeInt) { + return ir_implicit_cast(ira, target, dest_type); + } + + if (instr_is_comptime(target)) { + ConstExprValue *val = ir_resolve_const(ira, target, UndefBad); + if (val == nullptr) + return ira->codegen->invalid_instruction; + + IrInstruction *result = ir_const(ira, &instruction->base, dest_type); + bigint_truncate(&result->value.data.x_bigint, &val->data.x_bigint, + dest_type->data.integral.bit_count, dest_type->data.integral.is_signed); + return result; + } + + if (src_type->data.integral.bit_count == 0 || dest_type->data.integral.bit_count == 0) { IrInstruction *result = ir_const(ira, &instruction->base, dest_type); bigint_init_unsigned(&result->value.data.x_bigint, 0); return result; @@ -18507,13 +18522,6 @@ static IrInstruction *ir_analyze_instruction_truncate(IrAnalyze *ira, IrInstruct return ira->codegen->invalid_instruction; } - if (target->value.special == ConstValSpecialStatic) { - IrInstruction *result = ir_const(ira, &instruction->base, dest_type); - bigint_truncate(&result->value.data.x_bigint, &target->value.data.x_bigint, - dest_type->data.integral.bit_count, dest_type->data.integral.is_signed); - return result; - } - IrInstruction *new_instruction = ir_build_truncate(&ira->new_irb, instruction->base.scope, instruction->base.source_node, dest_type_value, target); new_instruction->value.type = dest_type; diff --git a/test/compile_errors.zig b/test/compile_errors.zig index de01a5ac45..b47cdf2ed1 100644 --- a/test/compile_errors.zig +++ b/test/compile_errors.zig @@ -1,6 +1,15 @@ const tests = @import("tests.zig"); pub fn addCases(cases: *tests.CompileErrorContext) void { + cases.addTest( + "@truncate undefined value", + \\export fn entry() void { + \\ var z = @truncate(u8, u16(undefined)); + \\} + , + ".tmp_source.zig:2:30: error: use of undefined value", + ); + cases.addTest( "return invalid type from test", \\test "example" { return 1; } @@ -3335,7 +3344,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void { cases.add( "truncate sign mismatch", \\fn f() i8 { - \\ const x: u32 = 10; + \\ var x: u32 = 10; \\ return @truncate(i8, x); \\} \\ diff --git a/test/stage1/behavior/truncate.zig b/test/stage1/behavior/truncate.zig index c195b64cbf..568346369f 100644 --- a/test/stage1/behavior/truncate.zig +++ b/test/stage1/behavior/truncate.zig @@ -6,3 +6,26 @@ test "truncate u0 to larger integer allowed and has comptime known result" { const y = @truncate(u8, x); comptime expect(y == 0); } + +test "truncate.u0.literal" { + var z = @truncate(u0, 0); + expect(z == 0); +} + +test "truncate.u0.const" { + const c0: usize = 0; + var z = @truncate(u0, c0); + expect(z == 0); +} + +test "truncate.u0.var" { + var d: u8 = 2; + var z = @truncate(u0, d); + expect(z == 0); +} + +test "truncate sign mismatch but comptime known so it works anyway" { + const x: u32 = 10; + var result = @truncate(i8, x); + expect(result == 10); +} -- cgit v1.2.3