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Merge branch 'wip/smcv/ubsan-half-float' into 'main'

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gsk, testsuite: Avoid undefined behaviour converting float <-> fp16

See merge request GNOME/gtk!7509
This commit is contained in:
Matthias Clasen
2024-07-28 02:59:59 +00:00
parent 785709d51c 660c6c8d6f
commit ffe82b7641
4 changed files with 86 additions and 138 deletions
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32
gsk/gl/fp16.c
View File

@@ -22,38 +22,6 @@
#include "fp16private.h"
static inline guint
as_uint (const float x)
{
return *(guint*)&x;
}
static inline float
as_float (const guint x)
{
return *(float*)&x;
}
// IEEE-754 16-bit floating-point format (without infinity): 1-5-10
static inline float
half_to_float_one (const guint16 x)
{
const guint e = (x&0x7C00)>>10; // exponent
const guint m = (x&0x03FF)<<13; // mantissa
const guint v = as_uint((float)m)>>23;
return as_float((x&0x8000)<<16 | (e!=0)*((e+112)<<23|m) | ((e==0)&(m!=0))*((v-37)<<23|((m<<(150-v))&0x007FE000)));
}
static inline guint16
float_to_half_one (const float x)
{
const guint b = as_uint(x)+0x00001000; // round-to-nearest-even
const guint e = (b&0x7F800000)>>23; // exponent
const guint m = b&0x007FFFFF; // mantissa
return (b&0x80000000)>>16 | (e>112)*((((e-112)<<10)&0x7C00)|m>>13) | ((e<113)&(e>101))*((((0x007FF000+m)>>(125-e))+1)>>1) | (e>143)*0x7FFF; // sign : normalized : denormalized : saturate
}
void
float_to_half4_c (const float f[4],
guint16 h[4])

51
gsk/gl/fp16private.h
View File

@@ -28,6 +28,57 @@ G_BEGIN_DECLS
#define FP16_ONE ((guint16)15360)
#define FP16_MINUS_ONE ((guint16)48128)
static inline guint
as_uint (const float x)
{
return *(guint*)&x;
}
static inline float
as_float (const guint x)
{
return *(float*)&x;
}
// IEEE-754 16-bit floating-point format (without infinity): 1-5-10
static inline float
half_to_float_one (const guint16 x)
{
const guint e = (x & 0x7C00) >> 10; // exponent
const guint m = (x & 0x03FF) << 13; // mantissa
const guint v = as_uint ((float) m) >> 23;
guint normalized = 0;
guint denormalized = 0;
if (e != 0)
normalized = (e + 112) << 23 | m;
if (e == 0 && m != 0)
denormalized = (v - 37) << 23 | ((m << (150 - v)) & 0x007FE000);
return as_float ((x & 0x8000u) << 16 | normalized | denormalized);
}
static inline guint16
float_to_half_one (const float x)
{
const guint b = *(guint*)&x+0x00001000; // round-to-nearest-even
const guint e = (b&0x7F800000)>>23; // exponent
const guint m = b&0x007FFFFF; // mantissa
guint n0 = 0;
guint n1 = 0;
guint n2 = 0;
if (e > 112)
n0 = (((e - 112) << 10) & 0x7C00) | m >> 13;
if (e < 113 && e > 101)
n1 = (((0x007FF000 + m) >> (125- e)) + 1) >> 1;
if (e > 143)
n2 = 0x7FFF;
return (b & 0x80000000) >> 16 | n0 | n1 | n2; // sign : normalized : denormalized : saturate
}
void float_to_half4 (const float f[4],
guint16 h[4]);

79
testsuite/gdk/memorytexture.c
View File

@@ -2,6 +2,8 @@
#include <epoxy/gl.h>
#include "gsk/gl/fp16private.h"
#define N 10
static GdkGLContext *gl_context = NULL;
@@ -44,49 +46,6 @@ struct _TextureBuilder
gsize offset;
};
static inline guint
as_uint (const float x)
{
return *(guint*)&x;
}
static inline float
as_float (const guint x)
{
return *(float*)&x;
}
// IEEE-754 16-bit floating-point format (without infinity): 1-5-10
//
static inline float
half_to_float (const guint16 x)
{
const guint e = (x&0x7C00)>>10; // exponent
const guint m = (x&0x03FF)<<13; // mantissa
const guint v = as_uint((float)m)>>23;
return as_float((x&0x8000)<<16 | (e!=0)*((e+112)<<23|m) | ((e==0)&(m!=0))*((v-37)<<23|((m<<(150-v))&0x007FE000)));
}
static inline guint16
float_to_half (const float x)
{
const guint b = *(guint*)&x+0x00001000; // round-to-nearest-even
const guint e = (b&0x7F800000)>>23; // exponent
const guint m = b&0x007FFFFF; // mantissa
guint n0 = 0;
guint n1 = 0;
guint n2 = 0;
if (e > 112)
n0 = (((e - 112) << 10) & 0x7C00) | m >> 13;
if (e < 113 && e > 101)
n1 = (((0x007FF000 + m) >> (125- e)) + 1) >> 1;
if (e > 143)
n2 = 0x7FFF;
return (b & 0x80000000) >> 16 | n0 | n1 | n2; // sign : normalized : denormalized : saturate
}
static gsize
gdk_memory_format_bytes_per_pixel (GdkMemoryFormat format)
{
@@ -432,7 +391,7 @@ gdk_memory_format_pixel_print (GdkMemoryFormat format,
case GDK_MEMORY_R16G16B16_FLOAT:
{
const guint16 *data16 = (const guint16 *) data;
g_string_append_printf (string, "%f %f %f", half_to_float (data16[0]), half_to_float (data16[1]), half_to_float (data16[2]));
g_string_append_printf (string, "%f %f %f", half_to_float_one (data16[0]), half_to_float_one (data16[1]), half_to_float_one (data16[2]));
}
break;
@@ -440,13 +399,13 @@ gdk_memory_format_pixel_print (GdkMemoryFormat format,
case GDK_MEMORY_R16G16B16A16_FLOAT_PREMULTIPLIED:
{
const guint16 *data16 = (const guint16 *) data;
g_string_append_printf (string, "%f %f %f %f", half_to_float (data16[0]), half_to_float (data16[1]), half_to_float (data16[2]), half_to_float (data16[3]));
g_string_append_printf (string, "%f %f %f %f", half_to_float_one (data16[0]), half_to_float_one (data16[1]), half_to_float_one (data16[2]), half_to_float_one (data16[3]));
}
break;
case GDK_MEMORY_A16_FLOAT:
{
const guint16 *data16 = (const guint16 *) data;
g_string_append_printf (string, "%f", half_to_float (data16[0]));
g_string_append_printf (string, "%f", half_to_float_one (data16[0]));
}
break;
@@ -537,8 +496,8 @@ gdk_memory_format_pixel_equal (GdkMemoryFormat format,
guint i;
for (i = 0; i < gdk_memory_format_bytes_per_pixel (format) / sizeof (guint16); i++)
{
float f1 = half_to_float (((guint16 *) pixel1)[i]);
float f2 = half_to_float (((guint16 *) pixel2)[i]);
float f1 = half_to_float_one (((guint16 *) pixel1)[i]);
float f2 = half_to_float_one (((guint16 *) pixel2)[i]);
if (!G_APPROX_VALUE (f1, f2, accurate ? 1./65535 : 1./255))
return FALSE;
}
@@ -774,9 +733,9 @@ texture_builder_set_pixel (TextureBuilder *builder,
case GDK_MEMORY_R16G16B16_FLOAT:
{
guint16 pixels[3] = {
float_to_half (color->red * color->alpha),
float_to_half (color->green * color->alpha),
float_to_half (color->blue * color->alpha)
float_to_half_one (color->red * color->alpha),
float_to_half_one (color->green * color->alpha),
float_to_half_one (color->blue * color->alpha)
};
memcpy (data, pixels, 3 * sizeof (guint16));
}
@@ -784,10 +743,10 @@ texture_builder_set_pixel (TextureBuilder *builder,
case GDK_MEMORY_R16G16B16A16_FLOAT_PREMULTIPLIED:
{
guint16 pixels[4] = {
float_to_half (color->red * color->alpha),
float_to_half (color->green * color->alpha),
float_to_half (color->blue * color->alpha),
float_to_half (color->alpha)
float_to_half_one (color->red * color->alpha),
float_to_half_one (color->green * color->alpha),
float_to_half_one (color->blue * color->alpha),
float_to_half_one (color->alpha)
};
memcpy (data, pixels, 4 * sizeof (guint16));
}
@@ -795,10 +754,10 @@ texture_builder_set_pixel (TextureBuilder *builder,
case GDK_MEMORY_R16G16B16A16_FLOAT:
{
guint16 pixels[4] = {
float_to_half (color->red),
float_to_half (color->green),
float_to_half (color->blue),
float_to_half (color->alpha)
float_to_half_one (color->red),
float_to_half_one (color->green),
float_to_half_one (color->blue),
float_to_half_one (color->alpha)
};
memcpy (data, pixels, 4 * sizeof (guint16));
}
@@ -889,7 +848,7 @@ texture_builder_set_pixel (TextureBuilder *builder,
break;
case GDK_MEMORY_A16_FLOAT:
{
guint16 pixel = float_to_half (color->alpha);
guint16 pixel = float_to_half_one (color->alpha);
memcpy (data, &pixel, sizeof (guint16));
}
break;

62
testsuite/gsk/scaling.c
View File

@@ -2,6 +2,8 @@
#define N 10
#include "gsk/gl/fp16private.h"
struct {
const char *name;
GskRenderer * (*create_func) (void);
@@ -48,38 +50,6 @@ struct _TextureBuilder
gsize offset;
};
static inline guint
as_uint (const float x)
{
return *(guint*)&x;
}
static inline float
as_float (const guint x)
{
return *(float*)&x;
}
// IEEE-754 16-bit floating-point format (without infinity): 1-5-10
//
static inline float
half_to_float (const guint16 x)
{
const guint e = (x&0x7C00)>>10; // exponent
const guint m = (x&0x03FF)<<13; // mantissa
const guint v = as_uint((float)m)>>23;
return as_float((x&0x8000)<<16 | (e!=0)*((e+112)<<23|m) | ((e==0)&(m!=0))*((v-37)<<23|((m<<(150-v))&0x007FE000)));
}
static inline guint16
float_to_half (const float x)
{
const guint b = *(guint*)&x+0x00001000; // round-to-nearest-even
const guint e = (b&0x7F800000)>>23; // exponent
const guint m = b&0x007FFFFF; // mantissa
return (b&0x80000000)>>16 | (e>112)*((((e-112)<<10)&0x7C00)|m>>13) | ((e<113)&(e>101))*((((0x007FF000+m)>>(125-e))+1)>>1) | (e>143)*0x7FFF; // sign : normalized : denormalized : saturate
}
static gsize
gdk_memory_format_bytes_per_pixel (GdkMemoryFormat format)
{
@@ -350,8 +320,8 @@ gdk_memory_format_pixel_equal (GdkMemoryFormat format,
guint i;
for (i = 0; i < gdk_memory_format_bytes_per_pixel (format) / sizeof (guint16); i++)
{
float f1 = half_to_float (((guint16 *) pixel1)[i]);
float f2 = half_to_float (((guint16 *) pixel2)[i]);
float f1 = half_to_float_one (((guint16 *) pixel1)[i]);
float f2 = half_to_float_one (((guint16 *) pixel2)[i]);
if (!G_APPROX_VALUE (f1, f2, accurate ? 1./65535 : 1./255))
return FALSE;
}
@@ -567,9 +537,9 @@ texture_builder_set_pixel (TextureBuilder *builder,
case GDK_MEMORY_R16G16B16_FLOAT:
{
guint16 pixels[3] = {
float_to_half (color->red * color->alpha),
float_to_half (color->green * color->alpha),
float_to_half (color->blue * color->alpha)
float_to_half_one (color->red * color->alpha),
float_to_half_one (color->green * color->alpha),
float_to_half_one (color->blue * color->alpha)
};
memcpy (data, pixels, 3 * sizeof (guint16));
}
@@ -577,10 +547,10 @@ texture_builder_set_pixel (TextureBuilder *builder,
case GDK_MEMORY_R16G16B16A16_FLOAT_PREMULTIPLIED:
{
guint16 pixels[4] = {
float_to_half (color->red * color->alpha),
float_to_half (color->green * color->alpha),
float_to_half (color->blue * color->alpha),
float_to_half (color->alpha)
float_to_half_one (color->red * color->alpha),
float_to_half_one (color->green * color->alpha),
float_to_half_one (color->blue * color->alpha),
float_to_half_one (color->alpha)
};
memcpy (data, pixels, 4 * sizeof (guint16));
}
@@ -588,10 +558,10 @@ texture_builder_set_pixel (TextureBuilder *builder,
case GDK_MEMORY_R16G16B16A16_FLOAT:
{
guint16 pixels[4] = {
float_to_half (color->red),
float_to_half (color->green),
float_to_half (color->blue),
float_to_half (color->alpha)
float_to_half_one (color->red),
float_to_half_one (color->green),
float_to_half_one (color->blue),
float_to_half_one (color->alpha)
};
memcpy (data, pixels, 4 * sizeof (guint16));
}
@@ -682,7 +652,7 @@ texture_builder_set_pixel (TextureBuilder *builder,
break;
case GDK_MEMORY_A16_FLOAT:
{
guint16 pixel = float_to_half (color->alpha);
guint16 pixel = float_to_half_one (color->alpha);
memcpy (data, &pixel, sizeof (guint16));
}
break;