authorgravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2017-09-20 22:44:24-04:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2017-09-20 22:44:24-04:00
log9cdb5dec7aed4a1f692f4ddac034d1f944c0a837
tree51e4087be00b41366230a43f1a65602d4e01b4da
parenta5e4e205c8a9f2706300a4dc7ebe7cf3bfe093cd

parsec: cleaner shifting code for fixed size types

4 files changed, 76 insertions(+), 6 deletions(-)

src/analyze.cpp-4
...@@ -163,10 +163,6 @@ static TypeTableEntry *new_container_type_entry(TypeTableEntryId id, AstNode *so...@@ -163,10 +163,6 @@ static TypeTableEntry *new_container_type_entry(TypeTableEntryId id, AstNode *so
163 return entry;163 return entry;
164}164}
165165
166static uint8_t log2_u64(uint64_t x) {
167 return (63 - clzll(x));
168}
169
170static uint8_t bits_needed_for_unsigned(uint64_t x) {166static uint8_t bits_needed_for_unsigned(uint64_t x) {
171 if (x == 0) {167 if (x == 0) {
172 return 0;168 return 0;
src/parsec.cpp+51
...@@ -347,9 +347,60 @@ static AstNode* trans_c_cast(Context *c, const SourceLocation &source_location,...@@ -347,9 +347,60 @@ static AstNode* trans_c_cast(Context *c, const SourceLocation &source_location,
347 return trans_create_node_fn_call_1(c, trans_qual_type(c, qt, source_location), expr);347 return trans_create_node_fn_call_1(c, trans_qual_type(c, qt, source_location), expr);
348}348}
349349
350static uint32_t qual_type_int_bit_width(Context *c, const QualType &qt, const SourceLocation &source_loc) {
351 const Type *ty = qt.getTypePtr();
352 switch (ty->getTypeClass()) {
353 case Type::Builtin:
354 {
355 const BuiltinType *builtin_ty = static_cast<const BuiltinType*>(ty);
356 switch (builtin_ty->getKind()) {
357 case BuiltinType::Char_U:
358 case BuiltinType::UChar:
359 case BuiltinType::Char_S:
360 case BuiltinType::SChar:
361 return 8;
362 case BuiltinType::UInt128:
363 case BuiltinType::Int128:
364 return 128;
365 default:
366 return 0;
367 }
368 zig_unreachable();
369 }
370 case Type::Typedef:
371 {
372 const TypedefType *typedef_ty = static_cast<const TypedefType*>(ty);
373 const TypedefNameDecl *typedef_decl = typedef_ty->getDecl();
374 const char *type_name = decl_name(typedef_decl);
375 if (strcmp(type_name, "uint8_t") == 0 || strcmp(type_name, "int8_t") == 0) {
376 return 8;
377 } else if (strcmp(type_name, "uint16_t") == 0 || strcmp(type_name, "int16_t") == 0) {
378 return 16;
379 } else if (strcmp(type_name, "uint32_t") == 0 || strcmp(type_name, "int32_t") == 0) {
380 return 32;
381 } else if (strcmp(type_name, "uint64_t") == 0 || strcmp(type_name, "int64_t") == 0) {
382 return 64;
383 } else {
384 return 0;
385 }
386 }
387 default:
388 return 0;
389 }
390 zig_unreachable();
391}
392
393
350static AstNode *qual_type_to_log2_int_ref(Context *c, const QualType &qt,394static AstNode *qual_type_to_log2_int_ref(Context *c, const QualType &qt,
351 const SourceLocation &source_loc)395 const SourceLocation &source_loc)
352{396{
397 uint32_t int_bit_width = qual_type_int_bit_width(c, qt, source_loc);
398 if (int_bit_width != 0) {
399 // we can perform the log2 now.
400 uint64_t cast_bit_width = log2_u64(int_bit_width);
401 return trans_create_node_symbol(c, buf_sprintf("u%" ZIG_PRI_u64, cast_bit_width));
402 }
403
353 AstNode *zig_type_node = trans_qual_type(c, qt, source_loc);404 AstNode *zig_type_node = trans_qual_type(c, qt, source_loc);
354405
355// @import("std").math.Log2Int(c_long);406// @import("std").math.Log2Int(c_long);
src/util.hpp+4
...@@ -147,4 +147,8 @@ bool uint64_eq(uint64_t a, uint64_t b);...@@ -147,4 +147,8 @@ bool uint64_eq(uint64_t a, uint64_t b);
147uint32_t ptr_hash(const void *ptr);147uint32_t ptr_hash(const void *ptr);
148bool ptr_eq(const void *a, const void *b);148bool ptr_eq(const void *a, const void *b);
149149
150static inline uint8_t log2_u64(uint64_t x) {
151 return (63 - clzll(x));
152}
153
150#endif154#endif
test/parsec.zig+21-2
...@@ -315,12 +315,11 @@ pub fn addCases(cases: &tests.ParseCContext) {...@@ -315,12 +315,11 @@ pub fn addCases(cases: &tests.ParseCContext) {
315 \\pub const LUA_GLOBALSINDEX = -10002;315 \\pub const LUA_GLOBALSINDEX = -10002;
316 );316 );
317317
318 cases.add("sift right assign",318 cases.add("shift right assign",
319 \\int log2(unsigned a) {319 \\int log2(unsigned a) {
320 \\ int i = 0;320 \\ int i = 0;
321 \\ while (a > 0) {321 \\ while (a > 0) {
322 \\ a >>= 1;322 \\ a >>= 1;
323 \\ //i++;
324 \\ }323 \\ }
325 \\ return i;324 \\ return i;
326 \\}325 \\}
...@@ -334,4 +333,24 @@ pub fn addCases(cases: &tests.ParseCContext) {...@@ -334,4 +333,24 @@ pub fn addCases(cases: &tests.ParseCContext) {
334 \\ return i;333 \\ return i;
335 \\}334 \\}
336 );335 );
336
337 cases.add("shift right assign with a fixed size type",
338 \\#include <stdint.h>
339 \\int log2(uint32_t a) {
340 \\ int i = 0;
341 \\ while (a > 0) {
342 \\ a >>= 1;
343 \\ }
344 \\ return i;
345 \\}
346 ,
347 \\export fn log2(_arg_a: u32) -> c_int {
348 \\ var a = _arg_a;
349 \\ var i: c_int = 0;
350 \\ while (a > c_uint(0)) {
351 \\ a >>= u5(1);
352 \\ };
353 \\ return i;
354 \\}
355 );
337}356}