RISC-V: Add RV32E support.

	Kito Cheng <kito.cheng@gmail.com>
	Monk Chiang  <sh.chiang04@gmail.com>

	gcc/
	* common/config/riscv/riscv-common.c (riscv_parse_arch_string):
	Add support to parse rv32e*.  Clear MASK_RVE for rv32i and rv64i.
	* config.gcc (riscv*-*-*): Add support for rv32e* and ilp32e.
	* config/riscv/riscv-c.c (riscv_cpu_cpp_builtins): Define
	__riscv_32e when TARGET_RVE.  Handle ABI_ILP32E as soft-float ABI.
	* config/riscv/riscv-opts.h (riscv_abi_type): Add ABI_ILP32E.
	* config/riscv/riscv.c (riscv_compute_frame_info): When TARGET_RVE,
	compute save_libcall_adjustment properly.
	(riscv_option_override): Call error if TARGET_RVE and not ABI_ILP32E.
	(riscv_conditional_register_usage): Handle TARGET_RVE and ABI_ILP32E.
	* config/riscv/riscv.h (UNITS_PER_FP_ARG): Handle ABI_ILP32E.
	(STACK_BOUNDARY, ABI_STACK_BOUNDARY): Handle TARGET_RVE.
	(GP_REG_LAST, MAX_ARGS_IN_REGISTERS): Likewise.
	(ABI_SPEC): Handle mabi=ilp32e.
	* config/riscv/riscv.opt (abi_type): Add ABI_ILP32E.
	(RVE): Add RVE mask.
	* doc/invoke.texi (RISC-V options) <-mabi>: Add ilp32e info.
	<-march>: Add rv32e as an example.

	gcc/testsuite/
	* gcc.dg/stack-usage-1.c: Add support for rv32e.

	libgcc/
	* config/riscv/save-restore.S: Add support for rv32e.

Co-Authored-By: Jim Wilson <jimw@sifive.com>
Co-Authored-By: Monk Chiang <sh.chiang04@gmail.com>

From-SVN: r260384

11 files changed, 115 insertions, 16 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 581f050..145c3aa 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,26 @@
+2018-05-18  Kito Cheng  <kito.cheng@gmail.com>
+	    Monk Chiang  <sh.chiang04@gmail.com>
+	    Jim Wilson <jimw@sifive.com>
+
+	* common/config/riscv/riscv-common.c (riscv_parse_arch_string):
+	Add support to parse rv32e*.  Clear MASK_RVE for rv32i and rv64i.
+	* config.gcc (riscv*-*-*): Add support for rv32e* and ilp32e.
+	* config/riscv/riscv-c.c (riscv_cpu_cpp_builtins): Define
+	__riscv_32e when TARGET_RVE.  Handle ABI_ILP32E as soft-float ABI.
+	* config/riscv/riscv-opts.h (riscv_abi_type): Add ABI_ILP32E.
+	* config/riscv/riscv.c (riscv_compute_frame_info): When TARGET_RVE,
+	compute save_libcall_adjustment properly.
+	(riscv_option_override): Call error if TARGET_RVE and not ABI_ILP32E.
+	(riscv_conditional_register_usage): Handle TARGET_RVE and ABI_ILP32E.
+	* config/riscv/riscv.h (UNITS_PER_FP_ARG): Handle ABI_ILP32E.
+	(STACK_BOUNDARY, ABI_STACK_BOUNDARY): Handle TARGET_RVE.
+	(GP_REG_LAST, MAX_ARGS_IN_REGISTERS): Likewise.
+	(ABI_SPEC): Handle mabi=ilp32e.
+	* config/riscv/riscv.opt (abi_type): Add ABI_ILP32E.
+	(RVE): Add RVE mask.
+	* doc/invoke.texi (RISC-V options) <-mabi>: Add ilp32e info.
+	<-march>: Add rv32e as an example.
+
 2018-05-18  Marc Glisse  <marc.glisse@inria.fr>
 
 	PR c++/82899
diff --git a/gcc/common/config/riscv/riscv-common.c b/gcc/common/config/riscv/riscv-common.c
index 9db8301..8a78aeb 100644
--- a/gcc/common/config/riscv/riscv-common.c
+++ b/gcc/common/config/riscv/riscv-common.c
@@ -27,7 +27,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "flags.h"
 #include "diagnostic-core.h"
 
-/* Parse a RISC-V ISA string into an option mask.  */
+/* Parse a RISC-V ISA string into an option mask.  Must clear or set all arch
+   dependent mask bits, in case more than one -march string is passed.  */
 
 static void
 riscv_parse_arch_string (const char *isa, int *flags, location_t loc)
@@ -48,6 +49,8 @@ riscv_parse_arch_string (const char *isa, int *flags, location_t loc)
     {
       p++;
 
+      *flags &= ~MASK_RVE;
+
       *flags |= MASK_MUL;
       *flags |= MASK_ATOMIC;
       *flags |= MASK_HARD_FLOAT;
@@ -57,6 +60,8 @@ riscv_parse_arch_string (const char *isa, int *flags, location_t loc)
     {
       p++;
 
+      *flags &= ~MASK_RVE;
+
       *flags &= ~MASK_MUL;
       if (*p == 'm')
 	*flags |= MASK_MUL, p++;
@@ -77,6 +82,28 @@ riscv_parse_arch_string (const char *isa, int *flags, location_t loc)
 	    }
 	}
     }
+  else if (*p == 'e')
+    {
+      p++;
+
+      *flags |= MASK_RVE;
+
+      if (*flags & MASK_64BIT)
+	{
+	  error ("RV64E is not a valid base ISA");
+	  return;
+	}
+
+      *flags &= ~MASK_MUL;
+      if (*p == 'm')
+	*flags |= MASK_MUL, p++;
+
+      *flags &= ~MASK_ATOMIC;
+      if (*p == 'a')
+	*flags |= MASK_ATOMIC, p++;
+
+      *flags &= ~(MASK_HARD_FLOAT | MASK_DOUBLE_FLOAT);
+    }
   else
     {
       error_at (loc, "-march=%s: invalid ISA string", isa);
diff --git a/gcc/config.gcc b/gcc/config.gcc
index 8edd0cd..96ae6a8 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -4077,19 +4077,20 @@ case "${target}" in
 
 		# Infer arch from --with-arch, --target, and --with-abi.
 		case "${with_arch}" in
-		rv32i* | rv32g* | rv64i* | rv64g*)
+		rv32e* | rv32i* | rv32g* | rv64i* | rv64g*)
 			# OK.
 			;;
 		"")
 			# Infer XLEN, but otherwise assume GC.
 			case "${with_abi}" in
+			ilp32e) with_arch="rv32e" ;;
 			ilp32 | ilp32f | ilp32d) with_arch="rv32gc" ;;
 			lp64 | lp64f | lp64d) with_arch="rv64gc" ;;
 			*) with_arch="rv${xlen}gc" ;;
 			esac
 			;;
 		*)
-			echo "--with-arch=${with_arch} is not supported.  The argument must begin with rv32i, rv32g, rv64i, or rv64g." 1>&2
+			echo "--with-arch=${with_arch} is not supported.  The argument must begin with rv32e, rv32i, rv32g, rv64i, or rv64g." 1>&2
 			exit 1
 			;;
 		esac
@@ -4098,11 +4099,12 @@ case "${target}" in
 		# pick a default based on the ISA, preferring soft-float
 		# unless the D extension is present.
 		case "${with_abi}" in
-		ilp32 | ilp32f | ilp32d | lp64 | lp64f | lp64d)
+		ilp32 | ilp32e | ilp32f | ilp32d | lp64 | lp64f | lp64d)
 			;;
 		"")
 			case "${with_arch}" in
 			rv32*d* | rv32g*) with_abi=ilp32d ;;
+			rv32e*) with_abi=ilp32e ;;
 			rv32*) with_abi=ilp32 ;;
 			rv64*d* | rv64g*) with_abi=lp64d ;;
 			rv64*) with_abi=lp64 ;;
@@ -4116,7 +4118,7 @@ case "${target}" in
 
 		# Make sure ABI and ISA are compatible.
 		case "${with_abi},${with_arch}" in
-		ilp32,rv32* \
+		ilp32,rv32* | ilp32e,rv32e* \
 		| ilp32f,rv32*f* | ilp32f,rv32g* \
 		| ilp32d,rv32*d* | ilp32d,rv32g* \
 		| lp64,rv64* \
diff --git a/gcc/config/riscv/riscv-c.c b/gcc/config/riscv/riscv-c.c
index 391b5ee..513f974 100644
--- a/gcc/config/riscv/riscv-c.c
+++ b/gcc/config/riscv/riscv-c.c
@@ -39,6 +39,9 @@ riscv_cpu_cpp_builtins (cpp_reader *pfile)
   if (TARGET_RVC)
     builtin_define ("__riscv_compressed");
   
+  if (TARGET_RVE)
+    builtin_define ("__riscv_32e");
+
   if (TARGET_ATOMIC)
     builtin_define ("__riscv_atomic");
   
@@ -62,6 +65,7 @@ riscv_cpu_cpp_builtins (cpp_reader *pfile)
   switch (riscv_abi)
     {
     case ABI_ILP32:
+    case ABI_ILP32E:
     case ABI_LP64:
       builtin_define ("__riscv_float_abi_soft");
       break;
diff --git a/gcc/config/riscv/riscv-opts.h b/gcc/config/riscv/riscv-opts.h
index 3e10ab3..b7ed72e 100644
--- a/gcc/config/riscv/riscv-opts.h
+++ b/gcc/config/riscv/riscv-opts.h
@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 
 enum riscv_abi_type {
   ABI_ILP32,
+  ABI_ILP32E,
   ABI_ILP32F,
   ABI_ILP32D,
   ABI_LP64,
diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index b497588..9a9d9e1 100644
--- a/gcc/config/riscv/riscv.c
+++ b/gcc/config/riscv/riscv.c
@@ -3334,7 +3334,14 @@ riscv_compute_frame_info (void)
 
       /* Only use save/restore routines if they don't alter the stack size.  */
       if (RISCV_STACK_ALIGN (num_save_restore * UNITS_PER_WORD) == x_save_size)
-	frame->save_libcall_adjustment = x_save_size;
+	{
+	  /* Libcall saves/restores 3 registers at once, so we need to
+	     allocate 12 bytes for callee-saved register.  */
+	  if (TARGET_RVE)
+	    x_save_size = 3 * UNITS_PER_WORD;
+
+	  frame->save_libcall_adjustment = x_save_size;
+	}
 
       offset += x_save_size;
     }
@@ -4147,6 +4154,9 @@ riscv_option_override (void)
     error ("requested ABI requires -march to subsume the %qc extension",
 	   UNITS_PER_FP_ARG > 8 ? 'Q' : (UNITS_PER_FP_ARG > 4 ? 'D' : 'F'));
 
+  if (TARGET_RVE && riscv_abi != ABI_ILP32E)
+    error ("rv32e requires ilp32e ABI");
+
   /* We do not yet support ILP32 on RV64.  */
   if (BITS_PER_WORD != POINTER_SIZE)
     error ("ABI requires -march=rv%d", POINTER_SIZE);
@@ -4171,6 +4181,19 @@ riscv_option_override (void)
 static void
 riscv_conditional_register_usage (void)
 {
+  /* We have only x0~x15 on RV32E.  */
+  if (TARGET_RVE)
+    {
+      for (int r = 16; r <= 31; r++)
+	fixed_regs[r] = 1;
+    }
+
+  if (riscv_abi == ABI_ILP32E)
+    {
+      for (int r = 16; r <= 31; r++)
+	call_used_regs[r] = 1;
+    }
+
   if (!TARGET_HARD_FLOAT)
     {
       for (int regno = FP_REG_FIRST; regno <= FP_REG_LAST; regno++)
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 62279ff..a9111a4 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -102,9 +102,11 @@ along with GCC; see the file COPYING3.  If not see
 #define UNITS_PER_FP_REG (TARGET_DOUBLE_FLOAT ? 8 : 4)
 
 /* The largest type that can be passed in floating-point registers.  */
-#define UNITS_PER_FP_ARG					\
-  (riscv_abi == ABI_ILP32 || riscv_abi == ABI_LP64 ? 0 :	\
-   riscv_abi == ABI_ILP32F || riscv_abi == ABI_LP64F ? 4 : 8)	\
+#define UNITS_PER_FP_ARG						\
+  ((riscv_abi == ABI_ILP32 || riscv_abi == ABI_ILP32E			\
+    || riscv_abi == ABI_LP64)						\
+   ? 0 									\
+   : ((riscv_abi == ABI_ILP32F || riscv_abi == ABI_LP64F) ? 4 : 8))
 
 /* Set the sizes of the core types.  */
 #define SHORT_TYPE_SIZE 16
@@ -124,10 +126,10 @@ along with GCC; see the file COPYING3.  If not see
 #define FUNCTION_BOUNDARY (TARGET_RVC ? 16 : 32)
 
 /* The smallest supported stack boundary the calling convention supports.  */
-#define STACK_BOUNDARY (2 * BITS_PER_WORD)
+#define STACK_BOUNDARY (TARGET_RVE ? BITS_PER_WORD : 2 * BITS_PER_WORD)
 
 /* The ABI stack alignment.  */
-#define ABI_STACK_BOUNDARY 128
+#define ABI_STACK_BOUNDARY (TARGET_RVE ? BITS_PER_WORD : 128)
 
 /* There is no point aligning anything to a rounder boundary than this.  */
 #define BIGGEST_ALIGNMENT 128
@@ -260,7 +262,7 @@ along with GCC; see the file COPYING3.  If not see
 /* Internal macros to classify an ISA register's type.  */
 
 #define GP_REG_FIRST 0
-#define GP_REG_LAST  31
+#define GP_REG_LAST  (TARGET_RVE ? 15 : 31)
 #define GP_REG_NUM   (GP_REG_LAST - GP_REG_FIRST + 1)
 
 #define FP_REG_FIRST 32
@@ -490,7 +492,7 @@ enum reg_class
 #define GP_RETURN GP_ARG_FIRST
 #define FP_RETURN (UNITS_PER_FP_ARG == 0 ? GP_RETURN : FP_ARG_FIRST)
 
-#define MAX_ARGS_IN_REGISTERS 8
+#define MAX_ARGS_IN_REGISTERS (TARGET_RVE ? 6 : 8)
 
 /* Symbolic macros for the first/last argument registers.  */
 
@@ -870,6 +872,7 @@ extern unsigned riscv_stack_boundary;
 
 #define ABI_SPEC \
   "%{mabi=ilp32:ilp32}" \
+  "%{mabi=ilp32e:ilp32e}" \
   "%{mabi=ilp32f:ilp32f}" \
   "%{mabi=ilp32d:ilp32d}" \
   "%{mabi=lp64:lp64}" \
diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt
index b37ac75..1369322 100644
--- a/gcc/config/riscv/riscv.opt
+++ b/gcc/config/riscv/riscv.opt
@@ -45,6 +45,9 @@ EnumValue
 Enum(abi_type) String(ilp32) Value(ABI_ILP32)
 
 EnumValue
+Enum(abi_type) String(ilp32e) Value(ABI_ILP32E)
+
+EnumValue
 Enum(abi_type) String(ilp32f) Value(ABI_ILP32F)
 
 EnumValue
@@ -122,3 +125,5 @@ Mask(HARD_FLOAT)
 Mask(DOUBLE_FLOAT)
 
 Mask(RVC)
+
+Mask(RVE)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 44b0433..beba295 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -23025,7 +23025,9 @@ conventions are: @samp{ilp32}, @samp{ilp32f}, @samp{ilp32d}, @samp{lp64},
 @samp{lp64f}, and @samp{lp64d}.  Some calling conventions are impossible to
 implement on some ISAs: for example, @samp{-march=rv32if -mabi=ilp32d} is
 invalid because the ABI requires 64-bit values be passed in F registers, but F
-registers are only 32 bits wide.
+registers are only 32 bits wide.  There is also the @samp{ilp32e} ABI that can
+only be used with the @samp{rv32e} architecture.  This ABI is not well
+specified at present, and is subject to change.
 
 @item -mfdiv
 @itemx -mno-fdiv
@@ -23044,7 +23046,8 @@ these instructions.
 @item -march=@var{ISA-string}
 @opindex march
 Generate code for given RISC-V ISA (e.g.@ @samp{rv64im}).  ISA strings must be
-lower-case.  Examples include @samp{rv64i}, @samp{rv32g}, and @samp{rv32imaf}.
+lower-case.  Examples include @samp{rv64i}, @samp{rv32g}, @samp{rv32e}, and
+@samp{rv32imaf}.
 
 @item -mtune=@var{processor-string}
 @opindex mtune
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 76e0169..e757d80 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2018-05-18  Kito Cheng  <kito.cheng@gmail.com>
+
+	* gcc.dg/stack-usage-1.c: Add support for rv32e.
+
 2018-05-18  Marc Glisse  <marc.glisse@inria.fr>
 
 	PR c++/82899
diff --git a/gcc/testsuite/gcc.dg/stack-usage-1.c b/gcc/testsuite/gcc.dg/stack-usage-1.c
index 45d2c7b..038bd4e 100644
--- a/gcc/testsuite/gcc.dg/stack-usage-1.c
+++ b/gcc/testsuite/gcc.dg/stack-usage-1.c
@@ -64,7 +64,11 @@
 #    define SIZE 240
 #  endif
 #elif defined (__riscv)
-#  define SIZE 240
+#  if defined (__riscv_32e)
+#    define SIZE 252
+#  else
+#    define SIZE 240
+#  endif
 #elif defined (__AVR__)
 #if defined (__AVR_3_BYTE_PC__ )
 #  define SIZE 251 /* 256 - 2 bytes for Y - 3 bytes for return address */