| Message ID | 66aa7f61-7a7e-b788-c3e6-6ae31808ed62@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [wwwdocs] Mention -march=armv8.5-a and other new command line options for AArch64 and Arm for GCC 9 | expand |
Pinging and adding Gerald to the CC list. On 22/02/2019 10:45, Sudakshina Das wrote: > Hi > > This patch documents the addition of the new Armv8.5-A and corresponding > extensions in the gcc-9/changes.html. > As per https://gcc.gnu.org/about.html, I have used W3 Validator. > Is this ok for cvs? > > Thanks > Sudi
Hi Sudi, On 2/22/19 10:45 AM, Sudakshina Das wrote: > Hi > > This patch documents the addition of the new Armv8.5-A and corresponding > extensions in the gcc-9/changes.html. > As per https://gcc.gnu.org/about.html, I have used W3 Validator. > Is this ok for cvs? > > Thanks > Sudi Index: htdocs/gcc-9/changes.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-9/changes.html,v retrieving revision 1.43 diff -u -r1.43 changes.html --- htdocs/gcc-9/changes.html 21 Feb 2019 10:32:55 -0000 1.43 +++ htdocs/gcc-9/changes.html 21 Feb 2019 18:25:09 -0000 @@ -283,6 +283,19 @@ </p> <p>The intrinsics are defined by the ACLE specification.</p> </li> + <li> + The Armv8.5-A architecture is now supported. This can be used by specifying the + <code>-march=armv8.5-a</code> option. I tend to prefer the wording "... is now supported through the <code>-march=armv8.5-a</code> option". Otherwise it reads as the compiler "using" the architecture, whereas we usually talk about "targeting" an architecture. + </li> + <li> The Armv8.5-A architecture also adds some security features that are optional to all older + architecture versions. These are also supported now and only effect the assembler. + <ul> + <li> Speculation Barrier instruction using <code>-march=armv8-a+sb</code>.</li> + <li> Execution and Data Prediction Restriction instructions using <code>-march=armv8-a+predres</code>.</li> + <li> Speculative Store Bypass Safe instruction using <code>-march=armv8-a+ssbs</code>. This does not + require a compiler option for Arm and thus <code>-march=armv8-a+ssbs</code> is a AArch64 specific option.</li> "AArch64-specific" LGTM otherwise. Thanks, Kyrill + </ul> + </li> </ul> <h5 id="aarch64">AArch64 specific</h5> @@ -298,6 +311,22 @@ The default value is 16 (64Kb) and can be changed at configure time using the flag <code>--with-stack-clash-protection-guard-size=12|16</code>. </li> + <li> + The option <code>-msign-return-address=</code> has been deprecated. This has been replaced + by the new <code>-mbranch-protection=</code> option. This new option can now be used to + enable the return address signing as well as the new Branch Target Identification + feature of Armv8.5-A architecture. For more information on the arguments accepted by + this option, please refer to + <a href="https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#AArch64-Options"> + AArch64-Options</a>. + </li> + <li> The following optional extensions to Armv8.5-A architecture are also supported now and + only effect the assembler. + <ul> + <li> Random Number Generation instructions using <code>-march=armv8.5-a+rng</code>.</li> + <li> Memory Tagging Extension using <code>-march=armv8.5-a+memtag</code>.</li> + </ul> + </li> </ul> <h5 id="arm">Arm specific</h5>
Hi Kyrill On 12/03/2019 12:03, Kyrill Tkachov wrote: > Hi Sudi, > > On 2/22/19 10:45 AM, Sudakshina Das wrote: >> Hi >> >> This patch documents the addition of the new Armv8.5-A and corresponding >> extensions in the gcc-9/changes.html. >> As per https://gcc.gnu.org/about.html, I have used W3 Validator. >> Is this ok for cvs? >> >> Thanks >> Sudi > > > Index: htdocs/gcc-9/changes.html > =================================================================== > RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-9/changes.html,v > retrieving revision 1.43 > diff -u -r1.43 changes.html > --- htdocs/gcc-9/changes.html 21 Feb 2019 10:32:55 -0000 1.43 > +++ htdocs/gcc-9/changes.html 21 Feb 2019 18:25:09 -0000 > @@ -283,6 +283,19 @@ > </p> > <p>The intrinsics are defined by the ACLE specification.</p> > </li> > + <li> > + The Armv8.5-A architecture is now supported. This can be used by > specifying the > + <code>-march=armv8.5-a</code> option. > > > I tend to prefer the wording "... is now supported through the > <code>-march=armv8.5-a</code> option". > Otherwise it reads as the compiler "using" the architecture, whereas we > usually talk about "targeting" an architecture. > > + </li> > + <li> The Armv8.5-A architecture also adds some security features that > are optional to all older > + architecture versions. These are also supported now and only effect > the assembler. > + <ul> > + <li> Speculation Barrier instruction using > <code>-march=armv8-a+sb</code>.</li> > + <li> Execution and Data Prediction Restriction instructions using > <code>-march=armv8-a+predres</code>.</li> > + <li> Speculative Store Bypass Safe instruction using > <code>-march=armv8-a+ssbs</code>. This does not > + require a compiler option for Arm and thus > <code>-march=armv8-a+ssbs</code> is a AArch64 specific option.</li> > > "AArch64-specific" > > > LGTM otherwise. > Thanks, > Kyrill Thanks for the review and sorry for the delay in response. I had edited the language for adding new options in a few other places as well. Thanks Sudi > > + </ul> > + </li> > </ul> > > <h5 id="aarch64">AArch64 specific</h5> > @@ -298,6 +311,22 @@ > The default value is 16 (64Kb) and can be changed at configure > time using the flag > <code>--with-stack-clash-protection-guard-size=12|16</code>. > </li> > + <li> > + The option <code>-msign-return-address=</code> has been deprecated. > This has been replaced > + by the new <code>-mbranch-protection=</code> option. This new > option can now be used to > + enable the return address signing as well as the new Branch Target > Identification > + feature of Armv8.5-A architecture. For more information on the > arguments accepted by > + this option, please refer to > + <a > href="https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#AArch64-Options"> > > + AArch64-Options</a>. > + </li> > + <li> The following optional extensions to Armv8.5-A architecture are > also supported now and > + only effect the assembler. > + <ul> > + <li> Random Number Generation instructions using > <code>-march=armv8.5-a+rng</code>.</li> > + <li> Memory Tagging Extension using > <code>-march=armv8.5-a+memtag</code>.</li> > + </ul> > + </li> > </ul> > > <h5 id="arm">Arm specific</h5> > Index: htdocs/gcc-9/changes.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-9/changes.html,v retrieving revision 1.52 diff -u -r1.52 changes.html --- htdocs/gcc-9/changes.html 7 Mar 2019 14:40:06 -0000 1.52 +++ htdocs/gcc-9/changes.html 18 Mar 2019 18:55:24 -0000 @@ -342,6 +342,24 @@ </p> <p>The intrinsics are defined by the ACLE specification.</p> </li> + <li> + The Armv8.5-A architecture is now supported through the + <code>-march=armv8.5-a</code> option. + </li> + <li> The Armv8.5-A architecture also adds some security features that are + optional to all older architecture versions. These are also supported now + and only effect the assembler. + <ul> + <li> Speculation Barrier instruction through the + <code>-march=armv8-a+sb</code> option.</li> + <li> Execution and Data Prediction Restriction instructions through + the <code>-march=armv8-a+predres</code> option.</li> + <li> Speculative Store Bypass Safe instruction through the + <code>-march=armv8-a+ssbs</code> option. This does not require a + compiler option for Arm and thus <code>-march=armv8-a+ssbs</code> + is an AArch64-specific option.</li> + </ul> + </li> </ul> <h5 id="aarch64">AArch64 specific</h5> @@ -362,6 +380,23 @@ The default value is 16 (64Kb) and can be changed at configure time using the flag <code>--with-stack-clash-protection-guard-size=12|16</code>. </li> + <li> + The option <code>-msign-return-address=</code> has been deprecated. This + has been replaced by the new <code>-mbranch-protection=</code> option. This + new option can now be used to enable the return address signing as well as + the new Branch Target Identification feature of Armv8.5-A architecture. For + more information on the arguments accepted by this option, please refer to + <a href="https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#AArch64-Options">AArch64-Options</a>. + </li> + <li> The following optional extensions to Armv8.5-A architecture are also + supported now and only effect the assembler. + <ul> + <li> Random Number Generation instructions through the + <code>-march=armv8.5-a+rng</code> option.</li> + <li> Memory Tagging Extension through the + <code>-march=armv8.5-a+memtag</code> option.</li> + </ul> + </li> </ul> <h5 id="arm">Arm specific</h5>
On Wed, Mar 20, 2019 at 10:17:41AM +0000, Sudakshina Das wrote: > Hi Kyrill > > On 12/03/2019 12:03, Kyrill Tkachov wrote: > > Hi Sudi, > > > > On 2/22/19 10:45 AM, Sudakshina Das wrote: > >> Hi > >> > >> This patch documents the addition of the new Armv8.5-A and corresponding > >> extensions in the gcc-9/changes.html. > >> As per https://gcc.gnu.org/about.html, I have used W3 Validator. > >> Is this ok for cvs? > >> > >> Thanks > >> Sudi > > > > > > Index: htdocs/gcc-9/changes.html > > =================================================================== > > RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-9/changes.html,v > > retrieving revision 1.43 > > diff -u -r1.43 changes.html > > --- htdocs/gcc-9/changes.html 21 Feb 2019 10:32:55 -0000 1.43 > > +++ htdocs/gcc-9/changes.html 21 Feb 2019 18:25:09 -0000 > > @@ -283,6 +283,19 @@ > > </p> > > <p>The intrinsics are defined by the ACLE specification.</p> > > </li> > > + <li> > > + The Armv8.5-A architecture is now supported. This can be used by > > specifying the > > + <code>-march=armv8.5-a</code> option. > > > > > > I tend to prefer the wording "... is now supported through the > > <code>-march=armv8.5-a</code> option". > > Otherwise it reads as the compiler "using" the architecture, whereas we > > usually talk about "targeting" an architecture. > > > > + </li> > > + <li> The Armv8.5-A architecture also adds some security features that > > are optional to all older > > + architecture versions. These are also supported now and only effect > > the assembler. > > + <ul> > > + <li> Speculation Barrier instruction using > > <code>-march=armv8-a+sb</code>.</li> > > + <li> Execution and Data Prediction Restriction instructions using > > <code>-march=armv8-a+predres</code>.</li> > > + <li> Speculative Store Bypass Safe instruction using > > <code>-march=armv8-a+ssbs</code>. This does not > > + require a compiler option for Arm and thus > > <code>-march=armv8-a+ssbs</code> is a AArch64 specific option.</li> > > > > "AArch64-specific" > > > > > > LGTM otherwise. > > Thanks, > > Kyrill > > Thanks for the review and sorry for the delay in response. I had edited > the language for adding new options in a few other places as well. > > + <li> The Armv8.5-A architecture also adds some security features that are > + optional to all older architecture versions. These are also supported now s/also supported now/now supported/ > + and only effect the assembler. s/effect/affect/ > + <ul> > + <li> Speculation Barrier instruction through the > + <code>-march=armv8-a+sb</code> option.</li> > + <li> Execution and Data Prediction Restriction instructions through > + the <code>-march=armv8-a+predres</code> option.</li> > + <li> Speculative Store Bypass Safe instruction through the > + <code>-march=armv8-a+ssbs</code> option. This does not require a > + compiler option for Arm and thus <code>-march=armv8-a+ssbs</code> > + is an AArch64-specific option.</li> > + </ul> > + </li> > </ul> > > <h5 id="aarch64">AArch64 specific</h5> > @@ -362,6 +380,23 @@ > The default value is 16 (64Kb) and can be changed at configure > time using the flag <code>--with-stack-clash-protection-guard-size=12|16</code>. > </li> > + <li> > + The option <code>-msign-return-address=</code> has been deprecated. This > + has been replaced by the new <code>-mbranch-protection=</code> option. This > + new option can now be used to enable the return address signing as well as > + the new Branch Target Identification feature of Armv8.5-A architecture. For > + more information on the arguments accepted by this option, please refer to > + <a href="https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#AArch64-Options">AArch64-Options</a>. > + </li> > + <li> The following optional extensions to Armv8.5-A architecture are also > + supported now and only effect the assembler. s/effect/affect/ > + <ul> > + <li> Random Number Generation instructions through the > + <code>-march=armv8.5-a+rng</code> option.</li> > + <li> Memory Tagging Extension through the > + <code>-march=armv8.5-a+memtag</code> option.</li> > + </ul> > + </li> > </ul> > > <h5 id="arm">Arm specific</h5> Otherwise, OK by me but feel free to wait for people with gooder grammar than me to have their say. Thanks, James
Hi James On 22/03/2019 16:25, James Greenhalgh wrote: > On Wed, Mar 20, 2019 at 10:17:41AM +0000, Sudakshina Das wrote: >> Hi Kyrill >> >> On 12/03/2019 12:03, Kyrill Tkachov wrote: >>> Hi Sudi, >>> >>> On 2/22/19 10:45 AM, Sudakshina Das wrote: >>>> Hi >>>> >>>> This patch documents the addition of the new Armv8.5-A and corresponding >>>> extensions in the gcc-9/changes.html. >>>> As per https://gcc.gnu.org/about.html, I have used W3 Validator. >>>> Is this ok for cvs? >>>> >>>> Thanks >>>> Sudi >>> >>> >>> Index: htdocs/gcc-9/changes.html >>> =================================================================== >>> RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-9/changes.html,v >>> retrieving revision 1.43 >>> diff -u -r1.43 changes.html >>> --- htdocs/gcc-9/changes.html 21 Feb 2019 10:32:55 -0000 1.43 >>> +++ htdocs/gcc-9/changes.html 21 Feb 2019 18:25:09 -0000 >>> @@ -283,6 +283,19 @@ >>> </p> >>> <p>The intrinsics are defined by the ACLE specification.</p> >>> </li> >>> + <li> >>> + The Armv8.5-A architecture is now supported. This can be used by >>> specifying the >>> + <code>-march=armv8.5-a</code> option. >>> >>> >>> I tend to prefer the wording "... is now supported through the >>> <code>-march=armv8.5-a</code> option". >>> Otherwise it reads as the compiler "using" the architecture, whereas we >>> usually talk about "targeting" an architecture. >>> >>> + </li> >>> + <li> The Armv8.5-A architecture also adds some security features that >>> are optional to all older >>> + architecture versions. These are also supported now and only effect >>> the assembler. >>> + <ul> >>> + <li> Speculation Barrier instruction using >>> <code>-march=armv8-a+sb</code>.</li> >>> + <li> Execution and Data Prediction Restriction instructions using >>> <code>-march=armv8-a+predres</code>.</li> >>> + <li> Speculative Store Bypass Safe instruction using >>> <code>-march=armv8-a+ssbs</code>. This does not >>> + require a compiler option for Arm and thus >>> <code>-march=armv8-a+ssbs</code> is a AArch64 specific option.</li> >>> >>> "AArch64-specific" >>> >>> >>> LGTM otherwise. >>> Thanks, >>> Kyrill >> >> Thanks for the review and sorry for the delay in response. I had edited >> the language for adding new options in a few other places as well. >> >> + <li> The Armv8.5-A architecture also adds some security features that are >> + optional to all older architecture versions. These are also supported now > > s/also supported now/now supported/ > >> + and only effect the assembler. > > s/effect/affect/ > >> + <ul> >> + <li> Speculation Barrier instruction through the >> + <code>-march=armv8-a+sb</code> option.</li> >> + <li> Execution and Data Prediction Restriction instructions through >> + the <code>-march=armv8-a+predres</code> option.</li> >> + <li> Speculative Store Bypass Safe instruction through the >> + <code>-march=armv8-a+ssbs</code> option. This does not require a >> + compiler option for Arm and thus <code>-march=armv8-a+ssbs</code> >> + is an AArch64-specific option.</li> >> + </ul> >> + </li> >> </ul> >> >> <h5 id="aarch64">AArch64 specific</h5> >> @@ -362,6 +380,23 @@ >> The default value is 16 (64Kb) and can be changed at configure >> time using the flag <code>--with-stack-clash-protection-guard-size=12|16</code>. >> </li> >> + <li> >> + The option <code>-msign-return-address=</code> has been deprecated. This >> + has been replaced by the new <code>-mbranch-protection=</code> option. This >> + new option can now be used to enable the return address signing as well as >> + the new Branch Target Identification feature of Armv8.5-A architecture. For >> + more information on the arguments accepted by this option, please refer to >> + <a href="https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#AArch64-Options">AArch64-Options</a>. >> + </li> >> + <li> The following optional extensions to Armv8.5-A architecture are also >> + supported now and only effect the assembler. > > s/effect/affect/ > >> + <ul> >> + <li> Random Number Generation instructions through the >> + <code>-march=armv8.5-a+rng</code> option.</li> >> + <li> Memory Tagging Extension through the >> + <code>-march=armv8.5-a+memtag</code> option.</li> >> + </ul> >> + </li> >> </ul> >> >> <h5 id="arm">Arm specific</h5> > > Otherwise, OK by me but feel free to wait for people with gooder > grammar than me to have their say. > Thanks for spotting those. So far no one else with gooder grammar has pointed out anything else. I will commit the patch with the changes you suggested on Monday if no one else has any other objections. Thanks Sudi > Thanks, > James >
Hi James On 29/03/2019 13:41, Sudakshina Das wrote: > Hi James > > On 22/03/2019 16:25, James Greenhalgh wrote: >> On Wed, Mar 20, 2019 at 10:17:41AM +0000, Sudakshina Das wrote: >>> Hi Kyrill >>> >>> On 12/03/2019 12:03, Kyrill Tkachov wrote: >>>> Hi Sudi, >>>> >>>> On 2/22/19 10:45 AM, Sudakshina Das wrote: >>>>> Hi >>>>> >>>>> This patch documents the addition of the new Armv8.5-A and >>>>> corresponding >>>>> extensions in the gcc-9/changes.html. >>>>> As per https://gcc.gnu.org/about.html, I have used W3 Validator. >>>>> Is this ok for cvs? >>>>> >>>>> Thanks >>>>> Sudi >>>> >>>> >>>> Index: htdocs/gcc-9/changes.html >>>> =================================================================== >>>> RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-9/changes.html,v >>>> retrieving revision 1.43 >>>> diff -u -r1.43 changes.html >>>> --- htdocs/gcc-9/changes.html 21 Feb 2019 10:32:55 -0000 1.43 >>>> +++ htdocs/gcc-9/changes.html 21 Feb 2019 18:25:09 -0000 >>>> @@ -283,6 +283,19 @@ >>>> </p> >>>> <p>The intrinsics are defined by the ACLE specification.</p> >>>> </li> >>>> + <li> >>>> + The Armv8.5-A architecture is now supported. This can be used by >>>> specifying the >>>> + <code>-march=armv8.5-a</code> option. >>>> >>>> >>>> I tend to prefer the wording "... is now supported through the >>>> <code>-march=armv8.5-a</code> option". >>>> Otherwise it reads as the compiler "using" the architecture, whereas we >>>> usually talk about "targeting" an architecture. >>>> >>>> + </li> >>>> + <li> The Armv8.5-A architecture also adds some security features >>>> that >>>> are optional to all older >>>> + architecture versions. These are also supported now and only >>>> effect >>>> the assembler. >>>> + <ul> >>>> + <li> Speculation Barrier instruction using >>>> <code>-march=armv8-a+sb</code>.</li> >>>> + <li> Execution and Data Prediction Restriction instructions using >>>> <code>-march=armv8-a+predres</code>.</li> >>>> + <li> Speculative Store Bypass Safe instruction using >>>> <code>-march=armv8-a+ssbs</code>. This does not >>>> + require a compiler option for Arm and thus >>>> <code>-march=armv8-a+ssbs</code> is a AArch64 specific option.</li> >>>> >>>> "AArch64-specific" >>>> >>>> >>>> LGTM otherwise. >>>> Thanks, >>>> Kyrill >>> >>> Thanks for the review and sorry for the delay in response. I had edited >>> the language for adding new options in a few other places as well. >>> >>> + <li> The Armv8.5-A architecture also adds some security features >>> that are >>> + optional to all older architecture versions. These are also >>> supported now >> >> s/also supported now/now supported/ >> >>> + and only effect the assembler. >> >> s/effect/affect/ >> >>> + <ul> >>> + <li> Speculation Barrier instruction through the >>> + <code>-march=armv8-a+sb</code> option.</li> >>> + <li> Execution and Data Prediction Restriction instructions through >>> + the <code>-march=armv8-a+predres</code> option.</li> >>> + <li> Speculative Store Bypass Safe instruction through the >>> + <code>-march=armv8-a+ssbs</code> option. This does not >>> require a >>> + compiler option for Arm and thus >>> <code>-march=armv8-a+ssbs</code> >>> + is an AArch64-specific option.</li> >>> + </ul> >>> + </li> >>> </ul> >>> <h5 id="aarch64">AArch64 specific</h5> >>> @@ -362,6 +380,23 @@ >>> The default value is 16 (64Kb) and can be changed at configure >>> time using the flag >>> <code>--with-stack-clash-protection-guard-size=12|16</code>. >>> </li> >>> + <li> >>> + The option <code>-msign-return-address=</code> has been >>> deprecated. This >>> + has been replaced by the new <code>-mbranch-protection=</code> >>> option. This >>> + new option can now be used to enable the return address signing >>> as well as >>> + the new Branch Target Identification feature of Armv8.5-A >>> architecture. For >>> + more information on the arguments accepted by this option, >>> please refer to >>> + <a >>> href="https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#AArch64-Options">AArch64-Options</a>. >>> >>> + </li> >>> + <li> The following optional extensions to Armv8.5-A architecture >>> are also >>> + supported now and only effect the assembler. >> >> s/effect/affect/ >> >>> + <ul> >>> + <li> Random Number Generation instructions through the >>> + <code>-march=armv8.5-a+rng</code> option.</li> >>> + <li> Memory Tagging Extension through the >>> + <code>-march=armv8.5-a+memtag</code> option.</li> >>> + </ul> >>> + </li> >>> </ul> >>> <h5 id="arm">Arm specific</h5> >> >> Otherwise, OK by me but feel free to wait for people with gooder >> grammar than me to have their say. >> > > Thanks for spotting those. So far no one else with gooder grammar has > pointed out anything else. I will commit the patch with the changes you > suggested on Monday if no one else has any other objections. > Committed as 1.56 Thanks Sudi > Thanks > Sudi > >> Thanks, >> James >> >
Index: htdocs/gcc-9/changes.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-9/changes.html,v retrieving revision 1.43 diff -u -r1.43 changes.html --- htdocs/gcc-9/changes.html 21 Feb 2019 10:32:55 -0000 1.43 +++ htdocs/gcc-9/changes.html 21 Feb 2019 18:25:09 -0000 @@ -283,6 +283,19 @@ </p> <p>The intrinsics are defined by the ACLE specification.</p> </li> + <li> + The Armv8.5-A architecture is now supported. This can be used by specifying the + <code>-march=armv8.5-a</code> option. + </li> + <li> The Armv8.5-A architecture also adds some security features that are optional to all older + architecture versions. These are also supported now and only effect the assembler. + <ul> + <li> Speculation Barrier instruction using <code>-march=armv8-a+sb</code>.</li> + <li> Execution and Data Prediction Restriction instructions using <code>-march=armv8-a+predres</code>.</li> + <li> Speculative Store Bypass Safe instruction using <code>-march=armv8-a+ssbs</code>. This does not + require a compiler option for Arm and thus <code>-march=armv8-a+ssbs</code> is a AArch64 specific option.</li> + </ul> + </li> </ul> <h5 id="aarch64">AArch64 specific</h5> @@ -298,6 +311,22 @@ The default value is 16 (64Kb) and can be changed at configure time using the flag <code>--with-stack-clash-protection-guard-size=12|16</code>. </li> + <li> + The option <code>-msign-return-address=</code> has been deprecated. This has been replaced + by the new <code>-mbranch-protection=</code> option. This new option can now be used to + enable the return address signing as well as the new Branch Target Identification + feature of Armv8.5-A architecture. For more information on the arguments accepted by + this option, please refer to + <a href="https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#AArch64-Options"> + AArch64-Options</a>. + </li> + <li> The following optional extensions to Armv8.5-A architecture are also supported now and + only effect the assembler. + <ul> + <li> Random Number Generation instructions using <code>-march=armv8.5-a+rng</code>.</li> + <li> Memory Tagging Extension using <code>-march=armv8.5-a+memtag</code>.</li> + </ul> + </li> </ul> <h5 id="arm">Arm specific</h5>