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[RISCVAsmParser] Allow a SymbolRef operand to be a complex expression 

So that instructions like `lla a5, (0xFF + end) - 4` (supported by GNU as) can
be parsed.

Add a missing test that an operand like `foo + foo` is not allowed.

Reviewed By: jrtc27

Differential Revision: https://reviews.llvm.org/D92293
This commit is contained in:
Fangrui Song 2020-12-01 16:08:09 -08:00
parent 07ab597bb0
commit e27e3ba9c9
3 changed files with 14 additions and 28 deletions
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34
llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
View File

@ -31,6 +31,7 @@
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/RISCVAttributes.h"
@ -1856,34 +1857,11 @@ bool RISCVAsmParser::classifySymbolRef(const MCExpr *Expr,
Expr = RE->getSubExpr();
}
// It's a simple symbol reference or constant with no addend.
if (isa<MCConstantExpr>(Expr) || isa<MCSymbolRefExpr>(Expr))
return true;
const MCBinaryExpr *BE = dyn_cast<MCBinaryExpr>(Expr);
if (!BE)
return false;
if (!isa<MCSymbolRefExpr>(BE->getLHS()))
return false;
if (BE->getOpcode() != MCBinaryExpr::Add &&
BE->getOpcode() != MCBinaryExpr::Sub)
return false;
// We are able to support the subtraction of two symbol references
if (BE->getOpcode() == MCBinaryExpr::Sub &&
isa<MCSymbolRefExpr>(BE->getRHS()))
return true;
// See if the addend is a constant, otherwise there's more going
// on here than we can deal with.
auto AddendExpr = dyn_cast<MCConstantExpr>(BE->getRHS());
if (!AddendExpr)
return false;
// It's some symbol reference + a constant addend
return Kind != RISCVMCExpr::VK_RISCV_Invalid;
MCValue Res;
MCFixup Fixup;
if (Expr->evaluateAsRelocatable(Res, nullptr, &Fixup))
return Res.getRefKind() == RISCVMCExpr::VK_RISCV_None;
return false;
}
bool RISCVAsmParser::ParseDirective(AsmToken DirectiveID) {

2
llvm/test/MC/RISCV/rvi-pseudos-invalid.s
View File

@ -27,3 +27,5 @@ sw a2, %lo(a_symbol)(a4), a3 # CHECK: :[[@LINE]]:27: error: invalid operand for
# Too few operands must be rejected
sw a2, a_symbol # CHECK: :[[@LINE]]:1: error: too few operands for instruction
la a1, foo+foo # CHECK: :[[@LINE]]:8: error: operand must be a bare symbol name

6
llvm/test/MC/RISCV/rvi-pseudos.s
View File

@ -181,3 +181,9 @@ lw a2, zero
# CHECK: auipc a4, %pcrel_hi(zero)
# CHECK: sw a3, %pcrel_lo(.Lpcrel_hi29)(a4)
sw a3, zero, a4
## Check that a complex expression can be simplified and matched.
# CHECK: .Lpcrel_hi30:
# CHECK: auipc a5, %pcrel_hi((255+a_symbol)-4)
# CHECK: addi a5, a5, %pcrel_lo(.Lpcrel_hi30)
lla a5, (0xFF + a_symbol) - 4