[PATCH][committed] aarch64: Extend -mtp= arguments

[PATCH][committed] aarch64: Extend -mtp= arguments

[Kyrylo Tkachov]

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Hi all,

After discussing the -mtp= option with Arm's LLVM developers we'd like to extend
the functionality of the option somewhat.
First of all, there is another TPIDR register that can be used to read the thread pointer:
TPIDRRO_EL0 (which can also be accessed by AArch32 under another name) so it makes sense
to add -mtp=tpidrr0_el0. This makes the existing arguments el0, el1, el2, el3 somewhat
inconsistent in their naming so this patch introduces the more "full" names
tpidr_el0, tpidr_el1, tpidr_el2, tpidr_el3 and makes the above short names alias of these new ones.
Long story short, we preserve backwards compatibility and add a new TPIDR register to access through
-mtp that wasn't available previously.
There is more relevant discussion of the options at https://reviews.llvm.org/D152433 if you're interested.

Bootstrapped and tested on aarch64-none-linux-gnu.
Pushing to trunk.
Thanks,
Kyrill

gcc/ChangeLog:

	PR target/108779
	* config/aarch64/aarch64-opts.h (enum aarch64_tp_reg): Add
	AARCH64_TPIDRRO_EL0 value.
	* config/aarch64/aarch64.cc (aarch64_output_load_tp):
	* config/aarch64/aarch64.opt (tpidr_el0, tpidr_el1, tpidr_el2,
	tpidr_el3, tpidrro_el3): New accepted values to -mtp=.
	* doc/invoke.texi (AArch64 Options): Document new -mtp= options.

gcc/testsuite/ChangeLog:

	PR target/108779
	* gcc.target/aarch64/mtp_5.c: New test.
	* gcc.target/aarch64/mtp_6.c: New test.
	* gcc.target/aarch64/mtp_7.c: New test.
	* gcc.target/aarch64/mtp_8.c: New test.
	* gcc.target/aarch64/mtp_9.c: New test.

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diff --git a/gcc/config/aarch64/aarch64-opts.h b/gcc/config/aarch64/aarch64-opts.h
index 9d5bf77c868dc6bebb37e04764ad42a58832996b..7e8f1babed8e6ab9b0b838cee25f169bc3851b7e 100644
--- a/gcc/config/aarch64/aarch64-opts.h
+++ b/gcc/config/aarch64/aarch64-opts.h
@@ -81,7 +81,8 @@ enum aarch64_tp_reg {
   AARCH64_TPIDR_EL0 = 0,
   AARCH64_TPIDR_EL1 = 1,
   AARCH64_TPIDR_EL2 = 2,
-  AARCH64_TPIDR_EL3 = 3
+  AARCH64_TPIDR_EL3 = 3,
+  AARCH64_TPIDRRO_EL0 = 4
 };
 
 /* SVE vector register sizes.  */
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 1f1f27e197dfeac67e75815350b6c825c1d9b55d..4c9a69cbdc9830119d9e0885383ced6b3b61f960 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -27671,7 +27671,8 @@ aarch64_indirect_call_asm (rtx addr)
 const char *
 aarch64_output_load_tp (rtx dest)
 {
-  const char *tpidrs[] = {"tpidr_el0", "tpidr_el1", "tpidr_el2", "tpidr_el3"};
+  const char *tpidrs[] = {"tpidr_el0", "tpidr_el1", "tpidr_el2",
+			  "tpidr_el3", "tpidrro_el0"};
   char buffer[64];
   snprintf (buffer, sizeof (buffer), "mrs\t%%0, %s",
 	    tpidrs[aarch64_tpidr_register]);
diff --git a/gcc/config/aarch64/aarch64.opt b/gcc/config/aarch64/aarch64.opt
index 025e52d40e5c52e122890f657e3cc930f164e9ea..4a0580435a8d3c92eca8936515026882c7ea7f48 100644
--- a/gcc/config/aarch64/aarch64.opt
+++ b/gcc/config/aarch64/aarch64.opt
@@ -104,15 +104,30 @@ The register used to access the thread pointer:
 EnumValue
 Enum(tp_reg) String(el0) Value(AARCH64_TPIDR_EL0)
 
+EnumValue
+Enum(tp_reg) String(tpidr_el0) Value(AARCH64_TPIDR_EL0)
+
 EnumValue
 Enum(tp_reg) String(el1) Value(AARCH64_TPIDR_EL1)
 
+EnumValue
+Enum(tp_reg) String(tpidr_el1) Value(AARCH64_TPIDR_EL1)
+
 EnumValue
 Enum(tp_reg) String(el2) Value(AARCH64_TPIDR_EL2)
 
+EnumValue
+Enum(tp_reg) String(tpidr_el2) Value(AARCH64_TPIDR_EL2)
+
 EnumValue
 Enum(tp_reg) String(el3) Value(AARCH64_TPIDR_EL3)
 
+EnumValue
+Enum(tp_reg) String(tpidr_el3) Value(AARCH64_TPIDR_EL3)
+
+EnumValue
+Enum(tp_reg) String(tpidrro_el0) Value(AARCH64_TPIDRRO_EL0)
+
 mtp=
 Target RejectNegative Joined Enum(tp_reg) Var(aarch64_tpidr_reg) Init(AARCH64_TPIDR_EL0) Save
 Specify the thread pointer register.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index ecbda956e1e567974f0c79f4990272e84a67845f..6ec2fbaf169afe406361ff04890b25cbee7b70d8 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -20234,12 +20234,12 @@ addresses and sizes of sections.  Programs can be statically linked only.  The
 @item -mtp=@var{name}
 @opindex mtp
 Specify the system register to use as a thread pointer.  The valid values
-are @samp{el0}, @samp{el1}, @samp{el2}, @samp{el3}.  These correspond to
-using the @samp{tpidr_el0}, @samp{tpidr_el1}, @samp{tpidr_el2},
-@samp{tpidr_el3} registers accordingly.  The default setting is @samp{el0}.
-It is recommended to compile all code intended to interoperate with the same
-value of this option to avoid accessing a different thread pointer from the
-wrong exception level.
+are @samp{tpidr_el0}, @samp{tpidrro_el0}, @samp{tpidr_el1}, @samp{tpidr_el2},
+@samp{tpidr_el3}.  For backwards compatibility the aliases @samp{el0},
+@samp{el1}, @samp{el2}, @samp{el3} are also accepted.
+The default setting is @samp{tpidr_el0}.  It is recommended to compile all
+code intended to interoperate with the same value of this option to avoid
+accessing a different thread pointer from the wrong exception level.
 
 @opindex mstrict-align
 @opindex mno-strict-align
diff --git a/gcc/testsuite/gcc.target/aarch64/mtp_5.c b/gcc/testsuite/gcc.target/aarch64/mtp_5.c
new file mode 100644
index 0000000000000000000000000000000000000000..72bd86169a5c446febdb00baf8a2725d3ef1708c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/mtp_5.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target tls_native } */
+/* { dg-options "-O -mtp=tpidrro_el0" } */
+
+#include "mtp.c"
+
+/* { dg-final { scan-assembler-times {mrs\tx[0-9]+, tpidrro_el0} 1 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/mtp_6.c b/gcc/testsuite/gcc.target/aarch64/mtp_6.c
new file mode 100644
index 0000000000000000000000000000000000000000..0cdee12f67dc64e11fc6cdb0d82a5da87bc271c7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/mtp_6.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target tls_native } */
+/* { dg-options "-O -mtp=tpidr_el0" } */
+
+#include "mtp.c"
+
+/* { dg-final { scan-assembler-times {mrs\tx[0-9]+, tpidr_el0} 1 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/mtp_7.c b/gcc/testsuite/gcc.target/aarch64/mtp_7.c
new file mode 100644
index 0000000000000000000000000000000000000000..2e4a1a4ee9b3122041ff610aee29c3083d5c0c20
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/mtp_7.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target tls_native } */
+/* { dg-options "-O -mtp=tpidr_el1" } */
+
+#include "mtp.c"
+
+/* { dg-final { scan-assembler-times {mrs\tx[0-9]+, tpidr_el1} 1 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/mtp_8.c b/gcc/testsuite/gcc.target/aarch64/mtp_8.c
new file mode 100644
index 0000000000000000000000000000000000000000..810fe38de9d473ed9633ab7162ba004009e0db2a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/mtp_8.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target tls_native } */
+/* { dg-options "-O -mtp=tpidr_el2" } */
+
+#include "mtp.c"
+
+/* { dg-final { scan-assembler-times {mrs\tx[0-9]+, tpidr_el2} 1 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/mtp_9.c b/gcc/testsuite/gcc.target/aarch64/mtp_9.c
new file mode 100644
index 0000000000000000000000000000000000000000..934cc18cbe8a0503ebe178e3d3bef3c1bcaff1c5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/mtp_9.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target tls_native } */
+/* { dg-options "-O -mtp=tpidr_el3" } */
+
+#include "mtp.c"
+
+/* { dg-final { scan-assembler-times {mrs\tx[0-9]+, tpidr_el3} 1 } } */