From 700c910cd1be1dcfd84f3a2bc4252a47999b9341 Mon Sep 17 00:00:00 2001 From: JF Bastien Date: Thu, 28 Jan 2016 09:01:07 -0800 Subject: Output NaN payloads only As discussed with @binji and @sunfish in https://github.com/WebAssembly/sexpr-wasm-prototype/issues/28 --- src/wasm.h | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'src/wasm.h') diff --git a/src/wasm.h b/src/wasm.h index 91c318034..367af082a 100644 --- a/src/wasm.h +++ b/src/wasm.h @@ -193,9 +193,12 @@ struct Literal { union { float ff; uint32_t ll; - } u; - u.ff = f; - o << "nan:0x" << std::hex << u.ll << std::dec; + } fu, iu; + fu.ff = f; + memcpy(&iu, &fu, sizeof(fu)); + bool sign = std::signbit(f); + uint32_t payload = ~0xffc00000u & iu.ll; + o << (sign ? "-" : "") << "nan:0x" << std::hex << payload << std::dec; return; } printDouble(o, f); @@ -210,9 +213,12 @@ struct Literal { union { double dd; uint64_t ll; - } u; - u.dd = d; - o << "nan:0x" << std::hex << u.ll << std::dec; + } du, iu; + du.dd = d; + memcpy(&iu, &du, sizeof(du)); + bool sign = std::signbit(d); + uint32_t payload = ~0xfff8000000000000ull & iu.ll; + o << (sign ? "" : "-") << "nan:0x" << std::hex << payload << std::dec; return; } if (!std::isfinite(d)) { -- cgit v1.2.3 From 76b1a52626151906b769d8537c16a5144b1cd3b3 Mon Sep 17 00:00:00 2001 From: JF Bastien Date: Thu, 28 Jan 2016 10:27:29 -0800 Subject: Don't emit NaN payload when zero. --- src/wasm.h | 18 +++++++++++------- test/llvm_autogenerated/immediates.wast | 8 ++++---- 2 files changed, 15 insertions(+), 11 deletions(-) (limited to 'src/wasm.h') diff --git a/src/wasm.h b/src/wasm.h index 367af082a..8cba16e8c 100644 --- a/src/wasm.h +++ b/src/wasm.h @@ -196,9 +196,11 @@ struct Literal { } fu, iu; fu.ff = f; memcpy(&iu, &fu, sizeof(fu)); - bool sign = std::signbit(f); - uint32_t payload = ~0xffc00000u & iu.ll; - o << (sign ? "-" : "") << "nan:0x" << std::hex << payload << std::dec; + const char *sign = std::signbit(f) ? "-" : ""; + o << sign << "nan"; + if (uint32_t payload = ~0xffc00000u & iu.ll) { + o << ":0x" << std::hex << payload << std::dec; + } return; } printDouble(o, f); @@ -216,13 +218,15 @@ struct Literal { } du, iu; du.dd = d; memcpy(&iu, &du, sizeof(du)); - bool sign = std::signbit(d); - uint32_t payload = ~0xfff8000000000000ull & iu.ll; - o << (sign ? "" : "-") << "nan:0x" << std::hex << payload << std::dec; + const char *sign = std::signbit(d) ? "-" : ""; + o << sign << "nan"; + if (uint64_t payload = ~0xfff8000000000000ull & iu.ll) { + o << ":0x" << std::hex << payload << std::dec; + } return; } if (!std::isfinite(d)) { - o << (d < 0 ? "-infinity" : "infinity"); + o << (std::signbit(d) ? "-infinity" : "infinity"); return; } const char *text = cashew::JSPrinter::numToString(d); diff --git a/test/llvm_autogenerated/immediates.wast b/test/llvm_autogenerated/immediates.wast index 19c8c0087..2a74f80e7 100644 --- a/test/llvm_autogenerated/immediates.wast +++ b/test/llvm_autogenerated/immediates.wast @@ -136,7 +136,7 @@ (block $fake_return_waka123 (block (br $fake_return_waka123 - (f32.const nan:0x0) + (f32.const nan) ) ) ) @@ -145,7 +145,7 @@ (block $fake_return_waka123 (block (br $fake_return_waka123 - (f32.const -nan:0x0) + (f32.const -nan) ) ) ) @@ -208,7 +208,7 @@ (block $fake_return_waka123 (block (br $fake_return_waka123 - (f64.const -nan:0x0) + (f64.const nan) ) ) ) @@ -217,7 +217,7 @@ (block $fake_return_waka123 (block (br $fake_return_waka123 - (f64.const nan:0x0) + (f64.const -nan) ) ) ) -- cgit v1.2.3 From 876c24812ae7660553b47797bb45461fcea1cc20 Mon Sep 17 00:00:00 2001 From: JF Bastien Date: Thu, 28 Jan 2016 10:42:01 -0800 Subject: Factor out bit_cast. --- src/support/utilities.h | 40 ++++++++++++++++++++++++++++++++++++++++ src/wasm.h | 17 +++-------------- 2 files changed, 43 insertions(+), 14 deletions(-) create mode 100644 src/support/utilities.h (limited to 'src/wasm.h') diff --git a/src/support/utilities.h b/src/support/utilities.h new file mode 100644 index 000000000..77263a78e --- /dev/null +++ b/src/support/utilities.h @@ -0,0 +1,40 @@ +/* + * Copyright 2016 WebAssembly Community Group participants + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef wasm_support_utilities_h +#define wasm_support_utilities_h + +#include +#include + +namespace wasm { + +// Type punning needs to be done through this function to avoid undefined +// behavior: unions and reinterpret_cast aren't valid approaches. +template +inline Destination bit_cast(const Source& source) { + static_assert(sizeof(Destination) == sizeof(Source), + "bit_cast needs to be between types of the same size"); + static_assert(std::is_pod::value, "non-POD bit_cast undefined"); + static_assert(std::is_pod::value, "non-POD bit_cast undefined"); + Destination destination; + std::memcpy(&destination, &source, sizeof(destination)); + return destination; +} + +} // namespace wasm + +#endif // wasm_support_utilities_h diff --git a/src/wasm.h b/src/wasm.h index 8cba16e8c..97e0bfc12 100644 --- a/src/wasm.h +++ b/src/wasm.h @@ -58,6 +58,7 @@ #include "emscripten-optimizer/simple_ast.h" #include "mixed_arena.h" #include "pretty_printing.h" +#include "support/utilities.h" namespace wasm { @@ -190,15 +191,9 @@ struct Literal { static void printFloat(std::ostream &o, float f) { if (isnan(f)) { - union { - float ff; - uint32_t ll; - } fu, iu; - fu.ff = f; - memcpy(&iu, &fu, sizeof(fu)); const char *sign = std::signbit(f) ? "-" : ""; o << sign << "nan"; - if (uint32_t payload = ~0xffc00000u & iu.ll) { + if (uint32_t payload = ~0xffc00000u & bit_cast(f)) { o << ":0x" << std::hex << payload << std::dec; } return; @@ -212,15 +207,9 @@ struct Literal { return; } if (isnan(d)) { - union { - double dd; - uint64_t ll; - } du, iu; - du.dd = d; - memcpy(&iu, &du, sizeof(du)); const char *sign = std::signbit(d) ? "-" : ""; o << sign << "nan"; - if (uint64_t payload = ~0xfff8000000000000ull & iu.ll) { + if (uint64_t payload = ~0xfff8000000000000ull & bit_cast(d)) { o << ":0x" << std::hex << payload << std::dec; } return; -- cgit v1.2.3