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[libc] Fix printf long double inf, bitcast in msan #70067

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Merged
merged 1 commit into from
Oct 24, 2023
Merged

[libc] Fix printf long double inf, bitcast in msan #70067

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5 changes: 4 additions & 1 deletion libc/src/__support/CPP/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,10 @@ add_header_library(
HDRS
bit.h
DEPENDS
libc.src.__support.macros.properties.compiler
.type_traits
libc.src.__support.macros.attributes
libc.src.__support.macros.config
libc.src.__support.macros.sanitizer
)

add_header_library(
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2 changes: 2 additions & 0 deletions libc/src/__support/CPP/bit.h
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Expand Up @@ -12,6 +12,7 @@
#include "src/__support/CPP/type_traits.h"
#include "src/__support/macros/attributes.h"
#include "src/__support/macros/config.h" // LIBC_HAS_BUILTIN
#include "src/__support/macros/sanitizer.h"

namespace LIBC_NAMESPACE::cpp {

Expand All @@ -31,6 +32,7 @@ LIBC_INLINE constexpr To bit_cast(const From &from) {
static_assert(cpp::is_trivially_copyable<To>::value &&
cpp::is_trivially_copyable<From>::value,
"Cannot bit-cast instances of non-trivially copyable classes.");
MSAN_UNPOISON(&from, sizeof(From));
#if defined(LLVM_LIBC_HAS_BUILTIN_BIT_CAST)
return __builtin_bit_cast(To, from);
#else
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4 changes: 2 additions & 2 deletions libc/src/stdio/printf_core/float_inf_nan_converter.h
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Expand Up @@ -34,13 +34,13 @@ LIBC_INLINE int convert_inf_nan(Writer *writer, const FormatSection &to_conv) {
fputil::FPBits<long double>::UIntType float_raw = to_conv.conv_val_raw;
fputil::FPBits<long double> float_bits(float_raw);
is_negative = float_bits.get_sign();
mantissa = float_bits.get_explicit_mantissa();
mantissa = float_bits.get_mantissa();
} else {
fputil::FPBits<double>::UIntType float_raw =
static_cast<fputil::FPBits<double>::UIntType>(to_conv.conv_val_raw);
fputil::FPBits<double> float_bits(float_raw);
is_negative = float_bits.get_sign();
mantissa = float_bits.get_explicit_mantissa();
mantissa = float_bits.get_mantissa();
}

char sign_char = 0;
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17 changes: 16 additions & 1 deletion libc/test/src/stdio/sprintf_test.cpp
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Expand Up @@ -572,7 +572,6 @@ TEST_F(LlvmLibcSPrintfTest, FloatHexExpConv) {
ForceRoundingMode r(RoundingMode::Nearest);
double inf = LIBC_NAMESPACE::fputil::FPBits<double>::inf().get_val();
double nan = LIBC_NAMESPACE::fputil::FPBits<double>::build_nan(1);

written = LIBC_NAMESPACE::sprintf(buff, "%a", 1.0);
ASSERT_STREQ_LEN(written, buff, "0x1p+0");

Expand Down Expand Up @@ -937,6 +936,10 @@ TEST_F(LlvmLibcSPrintfTest, FloatDecimalConv) {
ForceRoundingMode r(RoundingMode::Nearest);
double inf = LIBC_NAMESPACE::fputil::FPBits<double>::inf().get_val();
double nan = LIBC_NAMESPACE::fputil::FPBits<double>::build_nan(1);
long double ld_inf =
LIBC_NAMESPACE::fputil::FPBits<long double>::inf().get_val();
long double ld_nan =
LIBC_NAMESPACE::fputil::FPBits<long double>::build_nan(1);

char big_buff[10000]; // Used for long doubles and other extremely wide
// numbers.
Expand Down Expand Up @@ -996,6 +999,18 @@ TEST_F(LlvmLibcSPrintfTest, FloatDecimalConv) {
written = LIBC_NAMESPACE::sprintf(buff, "%F", -nan);
ASSERT_STREQ_LEN(written, buff, "-NAN");

written = LIBC_NAMESPACE::sprintf(buff, "%Lf", ld_inf);
ASSERT_STREQ_LEN(written, buff, "inf");

written = LIBC_NAMESPACE::sprintf(buff, "%LF", -ld_inf);
ASSERT_STREQ_LEN(written, buff, "-INF");

written = LIBC_NAMESPACE::sprintf(buff, "%Lf", ld_nan);
ASSERT_STREQ_LEN(written, buff, "nan");

written = LIBC_NAMESPACE::sprintf(buff, "%LF", -ld_nan);
ASSERT_STREQ_LEN(written, buff, "-NAN");

// Length Modifier Tests.

// TODO(michaelrj): Add tests for LONG_DOUBLE_IS_DOUBLE and 128 bit long
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1 change: 1 addition & 0 deletions utils/bazel/llvm-project-overlay/libc/BUILD.bazel
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Expand Up @@ -170,6 +170,7 @@ libc_support_library(
":__support_cpp_type_traits",
":__support_macros_attributes",
":__support_macros_config",
":__support_macros_sanitizer",
":libc_root",
],
)
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