[AArch64][compiler-rt] Only build SME ABI routines when compiler supports asm. (#68991)

This also adds the .variant_pcs directive to some functions from which
it was previously missing.

Author: sdesmalen-arm

compiler-rt/lib/builtins/CMakeLists.txt

@@ -551,10 +551,14 @@ set(aarch64_SOURCES
   ${GENERIC_SOURCES}
   cpu_model.c
   aarch64/fp_mode.c
-  aarch64/sme-abi.S
-  aarch64/sme-abi-init.c
 )
 
+if(COMPILER_RT_HAS_ASM_SME)
+  list(APPEND aarch64_SOURCES aarch64/sme-abi.S aarch64/sme-abi-init.c)
+else()
+  message(STATUS "AArch64 SME ABI routines disabled")
+endif()
+
 # Generate outline atomics helpers from lse.S base
 set(OA_HELPERS_DIR "${CMAKE_CURRENT_BINARY_DIR}/outline_atomic_helpers.dir")
 file(MAKE_DIRECTORY "${OA_HELPERS_DIR}")
@@ -782,7 +786,6 @@ else ()
   endif()
 
   append_list_if(COMPILER_RT_HAS_ASM_LSE HAS_ASM_LSE BUILTIN_DEFS)
-  append_list_if(COMPILER_RT_HAS_ASM_SME HAS_ASM_SME BUILTIN_DEFS)
 
   foreach (arch ${BUILTIN_SUPPORTED_ARCH})
     if (CAN_TARGET_${arch})

compiler-rt/lib/builtins/aarch64/sme-abi.S

@@ -8,29 +8,6 @@
 
 #include "../assembly.h"
 
-#ifdef HAS_ASM_SME
-#define ARCH armv9-a+sme
-#define SMSTOP_SM smstop sm
-#define SMSTOP_ZA smstop za
-#define REG_TPIDR2_EL0 TPIDR2_EL0
-#define REG_SVCR SVCR
-#define ADDSVL_X16_X16_1 addsvl x16, x16, #1
-#define LDR_ZA_W15_0_X16 ldr za[w15,0], [x16]
-#define STR_ZA_W15_0_X16 str za[w15,0], [x16]
-#define CNTD_X0 cntd x0
-#define CFI_OFFSET_VG_MINUS_16 .cfi_offset vg, -16
-#else
-#define ARCH armv8-a
-#define SMSTOP_SM .inst 0xd503427f
-#define SMSTOP_ZA .inst 0xd503447f
-#define REG_TPIDR2_EL0 S3_3_C13_C0_5
-#define REG_SVCR S3_3_C4_C2_2
-#define ADDSVL_X16_X16_1 .inst 0x04305830
-#define LDR_ZA_W15_0_X16 .inst 0xe1006200
-#define STR_ZA_W15_0_X16 .inst 0xe1206200
-#define CNTD_X0 .inst 0x04e0e3e0
-#define CFI_OFFSET_VG_MINUS_16 .cfi_escape 0x10, 0x2e, 0x03, 0x11, 0x70, 0x22 // $vg  @ cfa - 16
-#endif
 
 #if !defined(__APPLE__)
 #define TPIDR2_SYMBOL SYMBOL_NAME(__aarch64_has_sme_and_tpidr2_el0)
@@ -42,27 +19,27 @@
 #define TPIDR2_SYMBOL_OFFSET SYMBOL_NAME(__aarch64_has_sme_and_tpidr2_el0)@pageoff
 #endif
 
-.arch ARCH
+.arch armv9-a+sme
 
 // Utility function which calls a system's abort() routine. Because the function
 // is streaming-compatible it should disable streaming-SVE mode before calling
 // abort(). Note that there is no need to preserve any state before the call,
 // because the function does not return.
 DEFINE_COMPILERRT_PRIVATE_FUNCTION(do_abort)
 .cfi_startproc
-	.variant_pcs	SYMBOL_NAME(do_abort)
+	.variant_pcs SYMBOL_NAME(do_abort)
 	stp	x29, x30, [sp, #-32]!
-  CNTD_X0
+  cntd x0
   // Store VG to a stack location that we describe with .cfi_offset
   str x0, [sp, #16]
   .cfi_def_cfa_offset 32
   .cfi_offset w30, -24
   .cfi_offset w29, -32
-  CFI_OFFSET_VG_MINUS_16
+  .cfi_offset vg, -16
 	bl	__arm_sme_state
 	tbz	x0, #0, 2f
 1:
-	SMSTOP_SM
+	smstop sm
 2:
   // We can't make this into a tail-call because the unwinder would
   // need to restore the value of VG.
@@ -74,7 +51,7 @@ END_COMPILERRT_FUNCTION(do_abort)
 // that is set as part of the compiler-rt startup code.
 //   __aarch64_has_sme_and_tpidr2_el0
 DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_sme_state)
-	.variant_pcs	__arm_sme_state
+	.variant_pcs __arm_sme_state
   mov x0, xzr
   mov x1, xzr
 
@@ -83,18 +60,18 @@ DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_sme_state)
   cbz w16, 1f
 0:
   orr x0, x0, #0xC000000000000000
-  mrs x16, REG_SVCR
+  mrs x16, SVCR
   bfxil x0, x16, #0, #2
-  mrs x1, REG_TPIDR2_EL0
+  mrs x1, TPIDR2_EL0
 1:
   ret
 END_COMPILERRT_OUTLINE_FUNCTION(__arm_sme_state)
 
 DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_tpidr2_restore)
-	.variant_pcs	__arm_tpidr2_restore
+	.variant_pcs __arm_tpidr2_restore
   // If TPIDR2_EL0 is nonnull, the subroutine aborts in some platform-specific
   // manner.
-  mrs x14, REG_TPIDR2_EL0
+  mrs x14, TPIDR2_EL0
   cbnz  x14, 2f
 
   // If any of the reserved bytes in the first 16 bytes of BLK are nonzero,
@@ -114,8 +91,8 @@ DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_tpidr2_restore)
 
   mov x15, xzr
 0:
-  LDR_ZA_W15_0_X16
-  ADDSVL_X16_X16_1
+  ldr za[w15,0], [x16]
+  addsvl x16, x16, #1
   add x15, x15, #1
   cmp x14, x15
   b.ne  0b
@@ -126,14 +103,15 @@ DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_tpidr2_restore)
 END_COMPILERRT_OUTLINE_FUNCTION(__arm_tpidr2_restore)
 
 DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_tpidr2_save)
+	.variant_pcs __arm_tpidr2_restore
   // If the current thread does not have access to TPIDR2_EL0, the subroutine
   // does nothing.
   adrp  x14, TPIDR2_SYMBOL
   ldrb w14, [x14, TPIDR2_SYMBOL_OFFSET]
   cbz w14, 1f
 
   // If TPIDR2_EL0 is null, the subroutine does nothing.
-  mrs x16, REG_TPIDR2_EL0
+  mrs x16, TPIDR2_EL0
   cbz x16, 1f
 
   // If any of the reserved bytes in the first 16 bytes of the TPIDR2 block are
@@ -153,8 +131,8 @@ DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_tpidr2_save)
 
   mov x15, xzr
 0:
-  STR_ZA_W15_0_X16
-  ADDSVL_X16_X16_1
+  str za[w15,0], [x16]
+  addsvl x16, x16, #1
   add x15, x15, #1
   cmp x14, x15
   b.ne  0b
@@ -165,6 +143,7 @@ DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_tpidr2_save)
 END_COMPILERRT_OUTLINE_FUNCTION(__arm_tpidr2_save)
 
 DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_za_disable)
+	.variant_pcs __arm_tpidr2_restore
   // If the current thread does not have access to SME, the subroutine does
   // nothing.
   adrp  x14, TPIDR2_SYMBOL
@@ -182,10 +161,10 @@ DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(__arm_za_disable)
   bl  __arm_tpidr2_save
 
   // * Set TPIDR2_EL0 to null.
-  msr REG_TPIDR2_EL0, xzr
+  msr TPIDR2_EL0, xzr
 
   // * Set PSTATE.ZA to 0.
-  SMSTOP_ZA
+  smstop za
 
   .cfi_def_cfa wsp, 16
   ldp x29, x30, [sp], #16