+The assembler in Go 1.5 is a single new Go program that replaces
+the suite of C-language assemblers (6a,
+8a, etc.) in previous releases.
+The values of the environmetn variables
+GOARCH and GOOS
+choose which architecture and operating system the generated
+code will be for.
+This is practical because the assembly language syntax has always
+been idiosyncratic and nearly uniform across architectures;
+what differs is just the list of instructions available and the
+syntax of some addressing modes.
+With the variation easily configured at startup, a single
+assembler binary can cover all architectures.
+(See the updated assembler guide
+for more information about the language and some of
+the changes listed below.)
+
+The new assembler is very nearly compatible with the previous +one, but there are a few changes that may affect some +assembler source files. +
+ +
+First, the expression evaluation used for constants is a little
+different.
+It now uses unsigned 64-bit arithmetic and the precedence
+of operators (+, -, <<, etc.)
+comes from Go, not C.
+Since there are few assembly programs to start with, and few use
+complex arithmetic expressions,
+and of those even fewer will be affected by these changes, we expect
+almost no programs will need to be updated.
+
+Perhaps more important is that some discrepancies between the
+architectures in how the PC and SP are handled have been
+eliminated.
+Sometimes these registers represented hardware
+registers, and sometimes pseudo-registers.
+As of Go 1.5, the names PC and SP
+are always pseudo-registers.
+To refer to the hardware register, use the alternate representation such
+as R13 for the stack pointer and
+R15 for the hardware program counter on x86.
+(The names are different on other architectures.)
+To help enforce this change, references to the
+SP and PC
+pseudo-registers now always require an identifier:
+f+4(SP) not 4(SP);
+it is a syntax error to omit the identifier.
+Uses of SP (say) as a hardware register
+tend to omit the name, and they will now be flagged by
+the assembler.
+
+One minor change is that some of the old assemblers +permitted the notation +
+ ++constant=value ++ +
+to define a named constant.
+Since this is always possible to do with the traditional
+C-like #define notation, which is still
+supported (the assembler includes an implementation
+of a simplified C preprocessor), the feature was removed.
+
@@ -465,43 +521,86 @@ function that locates the rightmost byte with that value in the argument.
crypto package
+has a new interface, Decrypter,
+that abstracts the behavior of a private key used in asymmetric decryption.
crypto/cipher package,
+the documentation for the Stream
+interface has been clarified regarding the behavior when the source and destination are
+different lengths.
+If the destination is shorter than the source, the method will panic.
+This is not a change in the implementation, only the documentation.
crypto/cipher package,
+there is now support for nonce lengths other than 96 bytes in AES's Galois/Counter mode (GCM),
+which some protocols require.
crypto/elliptic package,
+there is now a Name field in the
+CurveParams struct,
+and the curves implemented in the package have been given names.
+These names provide a safer way to select a curve, as opposed to
+selecting its bit size, for cryptographic systems that are curve-dependent.
crypto/elliptic package,
+the Unmarshal function
+now verifies that the point is actually on the curve.
+(If it is not, the function returns nils).
+This change guards against certain attacks.
crypto/tls package
+now defaults to TLS 1.0.
+The old default, SSLv3, is still available through Config if needed.
crypto/tls package
+now supports Signed Certificate Timestamps (SCTs) as specified in RFC 6962.
+The server serves them if they are listed in the
+Certificate struct,
+and the client reqeusts them and exposes them, if present,
+in its ConnectionState struct.
+The crytpo/tls server implementation
+will also now always call the
+GetCertificate function in
+the Config struct
+to select a certificate for the connection when none is supplied.
crypto/tls package
+can now be rotated (changed periodically during an active connection).
+This is done through the new
+SetSessionTicketKeys
+method of the
+Config type.
crypto/x509 package,
+wildcards are now accepted only in the leftmost label as defined in
+the specification.
crypto/x509 package,
+the handling of unknown critical extensions has been changed.
+They used to cause parse errors but now they are parsed and caused errors only
+in Verify.
+The new field UnhandledCriticalExtensions of
+Certificate records these extensions.
Stats method
to retrieve database statistics.
debug/dwarf
+package has extensive additions to better support DWARF version 4.
+See for example the definition of the new type
+Class.
+debug/elf
+package now has support for the 64-bit Power architecture.
+encoding/base64 package
now supports unpadded encodings through two new encoding variables,
@@ -518,6 +629,20 @@ now supports unpadded encodings through two new encoding variables,
RawURLEncoding.
encoding/json package
+now returns an UnmarshalTypeError
+if a JSON value is not appropriate for the target variable or component
+to which it is being unmarshaled.
+flag package
+has a new function, UnquoteUsage,
+to assist in the creation of usage messages using the new convention
+described above.
+fmt package,
a value of type Value now
@@ -536,6 +661,9 @@ semicolon was implicitly added or was present in the source.
For forward compatibility the go/build package
reserves GOARCH values for a number of architectures that Go might support one day.
This is not a promise that it will.
+Also, the Package struct
+now has a PkgTargetRoot field that stores the
+architecture-dependent root directory in which to install, if known.
image package,
+the Rectangle type
+now implements the Image interface,
+mask image when drawing.
+image package,
+to assist in the handling of some JPEG images,
+there is now support for 4:1:1 and 4:1:0 YCbCr subsampling and basic
+CMYK support, represented by the new image.CMYK struct.
+image/color package
+adds basic CMYK support, through the new
+CMYK struct,
+the CMYKModel color model, and the
+CMYKToRGB function, as
+needed by some JPEG images.
+image/gif package
+includes a couple of generalizations.
+A multiple-frame GIF file can now have an overall bounds different
+from all the contained single frames' bounds.
+Also, the GIF struct
+now has a Disposal field
+that specifies the disposal method for each frame.
+io package
adds a CopyBuffer function
@@ -579,7 +740,16 @@ method for the Int type.
mime package adds an
+The mime package
+adds a new WordDecoder type
+to decode MIME headers containing RFC 204-encoded words.
+It also provides BEncoding and
+QEncoding
+as implementations of the encoding schemes of RFC 2045 and RFC 2047.
+mime package also adds an
ExtensionsByType
function that returns the MIME extensions know to be associated with a given MIME type.
Source field that holds the local
network address.
-net/http package now
has support for setting trailers from a server Handler.
@@ -627,6 +793,14 @@ in the ServeContent function.
As of Go 1.5, it now also ignores a time value equal to the Unix epoch.
net/http/fcgi package
+exports two new errors,
+ErrConnClosed and
+ErrRequestAborted,
+to report the corresponding error conditions.
+net/http/cgi package
had a bug that mishandled the values of the environment variables
@@ -662,6 +836,20 @@ adds new Ignore and
Reset functions.
runtime,
+runtime/pprof,
+and net/http/pprof packages
+each have new functions to support the tracing facilities described above:
+ReadTrace,
+StartTrace,
+StopTrace,
+StartTrace,
+StopTrace, and
+Trace.
+See the respective documentation for details.
+runtime/pprof package
by default now includes overall memory statistics in all memory profiles.