ARM IAS: support emitting constant values in target expressions

A 32-bit immediate value can be formed from a constant expression and loaded
into a register.  Add support to emit this into an object file.  Because this
value is a constant, a relocation must *not* be produced for it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199023 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Saleem Abdulrasool 2014-01-11 23:03:48 +00:00
parent ccdb9c9483
commit 8009754517
2 changed files with 51 additions and 0 deletions

View File

@ -26,6 +26,7 @@
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
@ -912,6 +913,20 @@ ARMMCCodeEmitter::getHiLo16ImmOpValue(const MCInst &MI, unsigned OpIdx,
const ARMMCExpr *ARM16Expr = cast<ARMMCExpr>(E);
E = ARM16Expr->getSubExpr();
if (const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(E)) {
const int64_t Value = MCE->getValue();
if (Value > UINT32_MAX)
report_fatal_error("constant value truncated (limited to 32-bit)");
switch (ARM16Expr->getKind()) {
case ARMMCExpr::VK_ARM_HI16:
return (int32_t(Value) & 0xffff0000) >> 16;
case ARMMCExpr::VK_ARM_LO16:
return (int32_t(Value) & 0x0000ffff);
default: llvm_unreachable("Unsupported ARMFixup");
}
}
switch (ARM16Expr->getKind()) {
default: llvm_unreachable("Unsupported ARMFixup");
case ARMMCExpr::VK_ARM_HI16:

View File

@ -1,4 +1,6 @@
@ RUN: llvm-mc -triple armv7-eabi -filetype asm -o - %s | FileCheck %s
@ RUN: llvm-mc -triple armv7-eabi -filetype obj -o - %s | llvm-readobj -r \
@ RUN: | FileCheck -check-prefix CHECK-RELOCATIONS %s
.syntax unified
@ -6,6 +8,9 @@
function:
bx lr
.global external
.type external,%function
.set deadbeat, 0xdeadbea7
.type test,%function
@ -28,6 +33,18 @@ test:
movw r5, #:lower16:0xD1510D6E
movt r5, #:upper16:0xD1510D6E
movw r0, :lower16:external
movt r0, :upper16:external
movw r1, #:lower16:external
movt r1, #:upper16:external
movw r2, #:lower16:(16 + 16)
movt r2, #:upper16:(16 + 16)
movw r3, :lower16:(16 + 16)
movt r3, :upper16:(16 + 16)
@ CHECK-LABEL: test:
@ CHECK: movw r0, :lower16:function
@ CHECK: movt r0, :upper16:function
@ -41,4 +58,23 @@ test:
@ CHECK: movt r4, :upper16:(3511749998)
@ CHECK: movw r5, :lower16:(3511749998)
@ CHECK: movt r5, :upper16:(3511749998)
@ CHECK: movw r0, :lower16:external
@ CHECK: movt r0, :upper16:external
@ CHECK: movw r1, :lower16:external
@ CHECK: movt r1, :upper16:external
@ CHECK: movw r2, :lower16:(32)
@ CHECK: movt r2, :upper16:(32)
@ CHECK: movw r3, :lower16:(32)
@ CHECK: movt r3, :upper16:(32)
@ CHECK-RELOCATIONS: Relocations [
@ CHECK-RELOCATIONS: 0x4 R_ARM_MOVW_ABS_NC function 0x0
@ CHECK-RELOCATIONS: 0x8 R_ARM_MOVT_ABS function 0x0
@ CHECK-RELOCATIONS: 0xC R_ARM_MOVW_ABS_NC function 0x0
@ CHECK-RELOCATIONS: 0x10 R_ARM_MOVT_ABS function 0x0
@ CHECK-RELOCATIONS: 0x34 R_ARM_MOVW_ABS_NC external 0x0
@ CHECK-RELOCATIONS: 0x38 R_ARM_MOVT_ABS external 0x0
@ CHECK-RELOCATIONS: 0x3C R_ARM_MOVW_ABS_NC external 0x0
@ CHECK-RELOCATIONS: 0x40 R_ARM_MOVT_ABS external 0x0
@ CHECK-RELOCATIONS: ]