RISC-V: Support assembler modifier %got_pcrel_hi.

gas/
	* config/tc-riscv.c: Support the modifier %got_pcrel_hi.
	* doc/c-riscv.texi: Add documentation.
	* testsuite/gas/riscv/no-relax-reloc.d: Add test case for the new
	modifier %got_pcrel_hi.
	* testsuite/gas/riscv/no-relax-reloc.s: Likewise.
	* testsuite/gas/riscv/relax-reloc.d: Likewise.
	* testsuite/gas/riscv/relax-reloc.s: Likewise.

gas/ChangeLog

@@ -1,5 +1,14 @@
 2020-03-04  Nelson Chu  <nelson.chu@sifive.com>
 
+	* config/tc-riscv.c (percent_op_utype): Support the modifier
+	%got_pcrel_hi.
+	* doc/c-riscv.texi: Add documentation.
+	* testsuite/gas/riscv/no-relax-reloc.d: Add test case for the new
+	modifier %got_pcrel_hi.
+	* testsuite/gas/riscv/no-relax-reloc.s: Likewise.
+	* testsuite/gas/riscv/relax-reloc.d: Likewise.
+	* testsuite/gas/riscv/relax-reloc.s: Likewise.
+
 	* doc/c-riscv.texi (relocation modifiers): Add documentation.
 	(RISC-V-Formats): Update the section name from "Instruction Formats"
 	to "RISC-V Instruction Formats".

gas/config/tc-riscv.c

@@ -1308,6 +1308,7 @@ static const struct percent_op_match percent_op_utype[] =
 {
   {"%tprel_hi", BFD_RELOC_RISCV_TPREL_HI20},
   {"%pcrel_hi", BFD_RELOC_RISCV_PCREL_HI20},
+  {"%got_pcrel_hi", BFD_RELOC_RISCV_GOT_HI20},
   {"%tls_ie_pcrel_hi", BFD_RELOC_RISCV_TLS_GOT_HI20},
   {"%tls_gd_pcrel_hi", BFD_RELOC_RISCV_TLS_GD_HI20},
   {"%hi", BFD_RELOC_RISCV_HI20},

gas/doc/c-riscv.texi

@@ -257,6 +257,23 @@ Or you can use the pseudo lla/lw/sw/... instruction to do this.
 	lla  a0, @var{symbol}
 @end smallexample
 
+@item %got_pcrel_hi(@var{symbol})
+The high 20 bits of relative address between pc and the GOT entry of
+@var{symbol}.  This is usually used with the %pcrel_lo modifier to access
+the GOT entry.
+
+@smallexample
+@var{label}:
+	auipc      a0, %got_pcrel_hi(@var{symbol}) // R_RISCV_GOT_HI20
+	addi       a0, a0, %pcrel_lo(@var{label})  // R_RISCV_PCREL_LO12_I
+
+@var{label}:
+	auipc      a0, %got_pcrel_hi(@var{symbol}) // R_RISCV_GOT_HI20
+	load/store a0, %pcrel_lo(@var{label})(a0)  // R_RISCV_PCREL_LO12_I/S
+@end smallexample
+
+Also, the pseudo la instruction with PIC has similar behavior.
+
 @item %tprel_add(@var{symbol})
 This is used purely to associate the R_RISCV_TPREL_ADD relocation for
 TLS relaxation.  This one is only valid as the fourth operand to the normally

gas/testsuite/gas/riscv/no-relax-reloc.d

@@ -9,4 +9,6 @@ RELOCATION RECORDS FOR .*
 0+4 R_RISCV_LO12_I.*
 0+8 R_RISCV_PCREL_HI20.*
 0+c R_RISCV_PCREL_LO12_I.*
-0+10 R_RISCV_CALL.*
+0+10 R_RISCV_GOT_HI20.*
+0+14 R_RISCV_PCREL_LO12_I.*
+0+18 R_RISCV_CALL.*

gas/testsuite/gas/riscv/no-relax-reloc.s

@@ -2,7 +2,10 @@ target:
 	lui	a5,%hi(target)
 	lw	a5,%lo(target)(a5)
 
-        .LA0: auipc     a5,%pcrel_hi(bar)
+	.LA0: auipc     a5,%pcrel_hi(symbol1)
-        lw      a0,%pcrel_lo(.LA0)(a5)
+	lw      a0,%pcrel_lo(.LA0)(a5)
+
+	.LA1: auipc     a5,%got_pcrel_hi(symbol2)
+	lw      a0,%pcrel_lo(.LA1)(a5)
 
 	call target

gas/testsuite/gas/riscv/relax-reloc.d

@@ -13,5 +13,8 @@ RELOCATION RECORDS FOR .*
 0+8 R_RISCV_RELAX.*
 0+c R_RISCV_PCREL_LO12_I.*
 0+c R_RISCV_RELAX.*
-0+10 R_RISCV_CALL.*
+0+10 R_RISCV_GOT_HI20.*
-0+10 R_RISCV_RELAX.*
+0+14 R_RISCV_PCREL_LO12_I.*
+0+14 R_RISCV_RELAX.*
+0+18 R_RISCV_CALL.*
+0+18 R_RISCV_RELAX.*

gas/testsuite/gas/riscv/relax-reloc.s

@@ -2,7 +2,10 @@ target:
 	lui	a5,%hi(target)
 	lw	a5,%lo(target)(a5)
 
-        .LA0: auipc     a5,%pcrel_hi(bar)
+	.LA0: auipc     a5,%pcrel_hi(symbol1)
-        lw      a0,%pcrel_lo(.LA0)(a5)
+	lw      a0,%pcrel_lo(.LA0)(a5)
+
+	.LA1: auipc     a5,%got_pcrel_hi(symbol2)
+	lw      a0,%pcrel_lo(.LA1)(a5)
 
 	call target