[RISCV][MC] Add support for evaluating constant symbols as immediates

This further improves compatibility with GNU as, allowing input such as the
following to be assembled:

.equ CONST, 0x123456
li a0, CONST
addi a0, a0, %lo(CONST)

.equ CONST, 1
slli a0, a0, CONST

Note that we don't have perfect compatibility with gas, as it will avoid
emitting a relocation in this case:

addi a0, a0, %lo(CONST2)
.equ CONST2, 0x123456

Thanks to Shiva Chen for suggesting a better way to approach this during review.

Differential Revision: https://reviews.llvm.org/D52298


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@350831 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index d7fc2b2..1d1112c 100644
--- a/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -1033,17 +1033,10 @@
   case AsmToken::Plus:
   case AsmToken::Integer:
   case AsmToken::String:
+  case AsmToken::Identifier:
     if (getParser().parseExpression(Res))
       return MatchOperand_ParseFail;
     break;
-  case AsmToken::Identifier: {
-    StringRef Identifier;
-    if (getParser().parseIdentifier(Identifier))
-      return MatchOperand_ParseFail;
-    MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
-    Res = MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, getContext());
-    break;
-  }
   case AsmToken::Percent:
     return parseOperandWithModifier(Operands);
   }
diff --git a/test/MC/RISCV/rv32i-aliases-valid.s b/test/MC/RISCV/rv32i-aliases-valid.s
index c10c544..f986672 100644
--- a/test/MC/RISCV/rv32i-aliases-valid.s
+++ b/test/MC/RISCV/rv32i-aliases-valid.s
@@ -82,6 +82,19 @@
 # CHECK-OBJ: R_RISCV_PCREL_LO12
 li a0, %pcrel_lo(foo)
 
+.equ CONST, 0x123456
+# CHECK-EXPAND: lui a0, 291
+# CHECK-EXPAND: addi a0, a0, 1110
+li a0, CONST
+# CHECK-EXPAND: lui a0, 291
+# CHECK-EXPAND: addi a0, a0, 1111
+li a0, CONST+1
+
+.equ CONST, 0x654321
+# CHECK-EXPAND: lui a0, 1620
+# CHECK-EXPAND: addi a0, a0, 801
+li a0, CONST
+
 # CHECK-INST: csrrs t4, instreth, zero
 # CHECK-ALIAS: rdinstreth t4
 rdinstreth x29
diff --git a/test/MC/RISCV/rv32i-valid.s b/test/MC/RISCV/rv32i-valid.s
index 0df53e6..85a841b 100644
--- a/test/MC/RISCV/rv32i-valid.s
+++ b/test/MC/RISCV/rv32i-valid.s
@@ -9,6 +9,8 @@
 # RUN:     | llvm-objdump -riscv-no-aliases -d -r - \
 # RUN:     | FileCheck -check-prefixes=CHECK-OBJ,CHECK-ASM-AND-OBJ %s
 
+.equ CONST, 30
+
 # CHECK-ASM-AND-OBJ: lui a0, 2
 # CHECK-ASM: encoding: [0x37,0x25,0x00,0x00]
 lui a0, 2
@@ -35,6 +37,12 @@
 # CHECK-OBJ: lui a0, 0
 # CHECK-OBJ: R_RISCV_HI20 foo
 lui a0, %hi(foo)
+# CHECK-ASM-AND-OBJ: lui a0, 30
+# CHECK-ASM: encoding: [0x37,0xe5,0x01,0x00]
+lui a0, CONST
+# CHECK-ASM-AND-OBJ: lui a0, 31
+# CHECK-ASM: encoding: [0x37,0xf5,0x01,0x00]
+lui a0, CONST+1
 
 # CHECK-ASM-AND-OBJ: auipc a0, 2
 # CHECK-ASM: encoding: [0x17,0x25,0x00,0x00]
@@ -53,6 +61,9 @@
 # CHECK-OBJ: auipc a0, 0
 # CHECK-OBJ: R_RISCV_PCREL_HI20 foo
 auipc a0, %pcrel_hi(foo)
+# CHECK-ASM-AND-OBJ: auipc a0, 30
+# CHECK-ASM: encoding: [0x17,0xe5,0x01,0x00]
+auipc a0, CONST
 
 # CHECK-ASM-AND-OBJ: jal a2, 1048574
 # CHECK-ASM: encoding: [0x6f,0xf6,0xff,0x7f]
@@ -70,6 +81,9 @@
 # CHECK-OBJ: jal a0, 0
 # CHECK-OBJ: R_RISCV_JAL a0
 jal a0, a0
+# CHECK-ASM-AND-OBJ: jal a0, 30
+# CHECK-ASM: encoding: [0x6f,0x05,0xe0,0x01]
+jal a0, CONST
 
 # CHECK-ASM-AND-OBJ: jalr a0, a1, -2048
 # CHECK-ASM: encoding: [0x67,0x85,0x05,0x80]
@@ -83,6 +97,9 @@
 # CHECK-ASM-AND-OBJ: jalr sp, zero, 256
 # CHECK-ASM: encoding: [0x67,0x01,0x00,0x10]
 jalr sp, zero, 256
+# CHECK-ASM-AND-OBJ: jalr a1, a2, 30
+# CHECK-ASM: encoding: [0xe7,0x05,0xe6,0x01]
+jalr a1, a2, CONST
 
 # CHECK-ASM-AND-OBJ: beq s1, s1, 102
 # CHECK-ASM: encoding: [0x63,0x83,0x94,0x06]
@@ -102,6 +119,9 @@
 # CHECK-ASM-AND-OBJ: bgeu s8, sp, 512
 # CHECK-ASM: encoding: [0x63,0x70,0x2c,0x20]
 bgeu s8, sp, 512
+# CHECK-ASM-AND-OBJ: bgeu t0, t1, 30
+# CHECK-ASM: encoding: [0x63,0xff,0x62,0x00]
+bgeu t0, t1, CONST
 
 # CHECK-ASM-AND-OBJ: lb s3, 4(ra)
 # CHECK-ASM: encoding: [0x83,0x89,0x40,0x00]
@@ -131,6 +151,9 @@
 # CHECK-OBJ: lhu t3, 0(t3)
 # CHECK-OBJ: R_RISCV_PCREL_LO12
 lhu t3, %pcrel_lo(foo)(t3)
+# CHECK-ASM-AND-OBJ: lb t0, 30(t1)
+# CHECK-ASM: encoding: [0x83,0x02,0xe3,0x01]
+lb t0, CONST(t1)
 
 # CHECK-ASM-AND-OBJ: sb a0, 2047(a2)
 # CHECK-ASM: encoding: [0xa3,0x0f,0xa6,0x7e]
@@ -144,6 +167,9 @@
 # CHECK-ASM-AND-OBJ: sw ra, 999(zero)
 # CHECK-ASM: encoding: [0xa3,0x23,0x10,0x3e]
 sw ra, 999(zero)
+# CHECK-ASM-AND-OBJ: sw a0, 30(t0)
+# CHECK-ASM: encoding: [0x23,0xaf,0xa2,0x00]
+sw a0, CONST(t0)
 
 # CHECK-ASM-AND-OBJ: addi ra, sp, 2
 # CHECK-ASM: encoding: [0x93,0x00,0x21,0x00]
@@ -153,6 +179,9 @@
 # CHECK-OBJ: addi ra, sp, 0
 # CHECK-OBJ: R_RISCV_LO12
 addi ra, sp, %lo(foo)
+# CHECK-ASM-AND-OBJ: addi ra, sp, 30
+# CHECK-ASM: encoding: [0x93,0x00,0xe1,0x01]
+addi ra, sp, CONST
 # CHECK-ASM-AND-OBJ: slti a0, a2, -20
 # CHECK-ASM: encoding: [0x13,0x25,0xc6,0xfe]
 slti a0, a2, -20
@@ -184,6 +213,9 @@
 # CHECK-ASM-AND-OBJ: srai a2, sp, 15
 # CHECK-ASM: encoding: [0x13,0x56,0xf1,0x40]
 srai a2, sp, 15
+# CHECK-ASM-AND-OBJ: slli t3, t3, 30
+# CHECK-ASM: encoding: [0x13,0x1e,0xee,0x01]
+slli t3, t3, CONST
 
 # CHECK-ASM-AND-OBJ: add ra, zero, zero
 # CHECK-ASM: encoding: [0xb3,0x00,0x00,0x00]
@@ -252,6 +284,8 @@
 # CHECK-ASM: encoding: [0x73,0x10,0x00,0xc0]
 unimp
 
+.equ CONST, 16
+
 # CHECK-ASM-AND-OBJ: csrrw t0, 4095, t1
 # CHECK-ASM: encoding: [0xf3,0x12,0xf3,0xff]
 csrrw t0, 0xfff, t1
diff --git a/test/MC/RISCV/rv64i-aliases-valid.s b/test/MC/RISCV/rv64i-aliases-valid.s
index 064a20c..a705525 100644
--- a/test/MC/RISCV/rv64i-aliases-valid.s
+++ b/test/MC/RISCV/rv64i-aliases-valid.s
@@ -118,6 +118,16 @@
 # CHECK-OBJ: R_RISCV_PCREL_LO12
 li a0, %pcrel_lo(foo)
 
+.equ CONST, 0x123456
+# CHECK-EXPAND: lui a0, 291
+# CHECK-EXPAND: addiw a0, a0, 1110
+li a0, CONST
+
+.equ CONST, 0x654321
+# CHECK-EXPAND: lui a0, 1620
+# CHECK-EXPAND: addiw a0, a0, 801
+li a0, CONST
+
 # CHECK-INST: subw t6, zero, ra
 # CHECK-ALIAS: negw t6, ra
 negw x31, x1
diff --git a/test/MC/RISCV/rv64i-valid.s b/test/MC/RISCV/rv64i-valid.s
index 337b996..dab502c 100644
--- a/test/MC/RISCV/rv64i-valid.s
+++ b/test/MC/RISCV/rv64i-valid.s
@@ -4,6 +4,8 @@
 # RUN:     | llvm-objdump -riscv-no-aliases -d -r - \
 # RUN:     | FileCheck -check-prefixes=CHECK-OBJ,CHECK-ASM-AND-OBJ %s
 
+.equ CONST, 31
+
 # CHECK-ASM-AND-OBJ: lwu zero, 4(ra)
 # CHECK-ASM: encoding: [0x03,0xe0,0x40,0x00]
 lwu x0, 4(x1)
@@ -49,6 +51,9 @@
 # CHECK-ASM-AND-OBJ: srai s10, s11, 31
 # CHECK-ASM: encoding: [0x13,0xdd,0xfd,0x41]
 srai x26, x27, 31
+# CHECK-ASM-AND-OBJ: srai s10, s11, 31
+# CHECK-ASM: encoding: [0x13,0xdd,0xfd,0x41]
+srai x26, x27, CONST
 
 # CHECK-ASM-AND-OBJ: addiw t3, t4, -2048
 # CHECK-ASM: encoding: [0x1b,0x8e,0x0e,0x80]
@@ -75,6 +80,9 @@
 # CHECK-ASM-AND-OBJ: sraiw a0, a1, 31
 # CHECK-ASM: encoding: [0x1b,0xd5,0xf5,0x41]
 sraiw a0, a1, 31
+# CHECK-ASM-AND-OBJ: sraiw a0, a1, 31
+# CHECK-ASM: encoding: [0x1b,0xd5,0xf5,0x41]
+sraiw a0, a1, CONST
 
 # CHECK-ASM-AND-OBJ: addw a2, a3, a4
 # CHECK-ASM: encoding: [0x3b,0x86,0xe6,0x00]