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[AVR] Wrap out-of-bounds relative jumps
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@Patryk27
Patryk27 committed Dec 22, 2024
1 parent 1b9805c commit 9fc7bb3
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Showing 5 changed files with 4,223 additions and 4,216 deletions.
52 changes: 32 additions & 20 deletions llvm/lib/Target/AVR/AVRDevices.td
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,18 @@ def FeatureSmallStack
"The device has an 8-bit "
"stack pointer">;

// The device potentially requires emitting rjmp that wraps across the flash
// boundary.
//
// We enable this for devices that have exactly 8 kB of flash memory and don't
// support the `jmp` instruction - with this feature enabled, we try to convert
// out-of-bounds relative jumps into in-bounds by wrapping the offset, e.g.
// `rjmp +5000` becomes `rjmp -3192`.
def FeatureWrappingRjmp
: SubtargetFeature<"wrappingrjmp", "HasWrappingRjmp", "true",
"The device potentially requires emitting rjmp that "
"wraps across the flash boundary">;

// The device supports the 16-bit GPR pair MOVW instruction.
def FeatureMOVW : SubtargetFeature<"movw", "HasMOVW", "true",
"The device supports the 16-bit MOVW "
Expand Down Expand Up @@ -239,7 +251,7 @@ class Device<string Name, Family Fam, ELFArch Arch,
// in AVR binutils. We do not replicate this.
def : Device<"avr1", FamilyAVR1, ELFArchAVR1>;
def : Device<"avr2", FamilyAVR2, ELFArchAVR2>;
def : Device<"avr25", FamilyAVR25, ELFArchAVR25>;
def : Device<"avr25", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"avr3", FamilyAVR3, ELFArchAVR3>;
def : Device<"avr31", FamilyAVR31, ELFArchAVR31>;
def : Device<"avr35", FamilyAVR35, ELFArchAVR35>;
Expand Down Expand Up @@ -274,11 +286,11 @@ def : Device<"at86rf401", FamilyAVR2, ELFArchAVR25, [FeatureMOVW, FeatureLPMX]>;
def : Device<"at90s4414", FamilyAVR2, ELFArchAVR2, [FeatureSmallStack]>;
def : Device<"at90s4433", FamilyAVR2, ELFArchAVR2, [FeatureSmallStack]>;
def : Device<"at90s4434", FamilyAVR2, ELFArchAVR2, [FeatureSmallStack]>;
def : Device<"at90s8515", FamilyAVR2, ELFArchAVR2>;
def : Device<"at90c8534", FamilyAVR2, ELFArchAVR2>;
def : Device<"at90s8535", FamilyAVR2, ELFArchAVR2>;
def : Device<"ata5272", FamilyAVR25, ELFArchAVR25>;
def : Device<"ata6616c", FamilyAVR25, ELFArchAVR25>;
def : Device<"at90s8515", FamilyAVR2, ELFArchAVR2, [FeatureWrappingRjmp]>;
def : Device<"at90c8534", FamilyAVR2, ELFArchAVR2, [FeatureWrappingRjmp]>;
def : Device<"at90s8535", FamilyAVR2, ELFArchAVR2, [FeatureWrappingRjmp]>;
def : Device<"ata5272", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"ata6616c", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny13", FamilyAVR25, ELFArchAVR25, [FeatureSmallStack]>;
def : Device<"attiny13a", FamilyAVR25, ELFArchAVR25, [FeatureSmallStack]>;
def : Device<"attiny2313", FamilyAVR25, ELFArchAVR25, [FeatureSmallStack]>;
Expand All @@ -288,24 +300,24 @@ def : Device<"attiny24a", FamilyAVR25, ELFArchAVR25, [FeatureSmallStack]>;
def : Device<"attiny4313", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny44", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny44a", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny84", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny84a", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny84", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny84a", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny25", FamilyAVR25, ELFArchAVR25, [FeatureSmallStack]>;
def : Device<"attiny45", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny85", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny85", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny261", FamilyAVR25, ELFArchAVR25, [FeatureSmallStack]>;
def : Device<"attiny261a", FamilyAVR25, ELFArchAVR25, [FeatureSmallStack]>;
def : Device<"attiny441", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny461", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny461a", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny841", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny861", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny861a", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny87", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny841", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny861", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny861a", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny87", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny43u", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny48", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny88", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny828", FamilyAVR25, ELFArchAVR25>;
def : Device<"attiny88", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"attiny828", FamilyAVR25, ELFArchAVR25, [FeatureWrappingRjmp]>;
def : Device<"at43usb355", FamilyAVR3, ELFArchAVR3>;
def : Device<"at76c711", FamilyAVR3, ELFArchAVR3>;
def : Device<"atmega103", FamilyAVR31, ELFArchAVR31>;
Expand All @@ -321,11 +333,11 @@ def : Device<"atmega16u2", FamilyAVR35, ELFArchAVR35>;
def : Device<"atmega32u2", FamilyAVR35, ELFArchAVR35>;
def : Device<"attiny1634", FamilyAVR35, ELFArchAVR35>;
def : Device<"atmega8", FamilyAVR2, ELFArchAVR4,
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM]>;
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM, FeatureWrappingRjmp]>;
def : Device<"ata6289", FamilyAVR4, ELFArchAVR4>;
def : Device<"atmega8a", FamilyAVR2, ELFArchAVR4,
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM]>;
def : Device<"ata6285", FamilyAVR4, ELFArchAVR4>;
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM, FeatureWrappingRjmp]>;
def : Device<"ata6285", FamilyAVR4, ELFArchAVR4, [FeatureWrappingRjmp]>;
def : Device<"ata6286", FamilyAVR4, ELFArchAVR4>;
def : Device<"ata6612c", FamilyAVR4, ELFArchAVR4>;
def : Device<"atmega48", FamilyAVR4, ELFArchAVR4>;
Expand All @@ -339,9 +351,9 @@ def : Device<"atmega88p", FamilyAVR4, ELFArchAVR4>;
def : Device<"atmega88pa", FamilyAVR4, ELFArchAVR4>;
def : Device<"atmega88pb", FamilyAVR4, ELFArchAVR4>;
def : Device<"atmega8515", FamilyAVR2, ELFArchAVR4,
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM]>;
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM, FeatureWrappingRjmp]>;
def : Device<"atmega8535", FamilyAVR2, ELFArchAVR4,
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM]>;
[FeatureMultiplication, FeatureMOVW, FeatureLPMX, FeatureSPM, FeatureWrappingRjmp]>;
def : Device<"atmega8hva", FamilyAVR4, ELFArchAVR4>;
def : Device<"at90pwm1", FamilyAVR4, ELFArchAVR4>;
def : Device<"at90pwm2", FamilyAVR4, ELFArchAVR4>;
Expand Down
69 changes: 35 additions & 34 deletions llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,16 +27,13 @@
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"

// FIXME: we should be doing checks to make sure asm operands
// are not out of bounds.

namespace adjust {

using namespace llvm;

static void signed_width(unsigned Width, uint64_t Value,
std::string Description, const MCFixup &Fixup,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
if (!isIntN(Width, Value)) {
std::string Diagnostic = "out of range " + Description;

Expand All @@ -46,17 +43,13 @@ static void signed_width(unsigned Width, uint64_t Value,
Diagnostic += " (expected an integer in the range " + std::to_string(Min) +
" to " + std::to_string(Max) + ")";

if (Ctx) {
Ctx->reportError(Fixup.getLoc(), Diagnostic);
} else {
llvm_unreachable(Diagnostic.c_str());
}
Ctx->reportError(Fixup.getLoc(), Diagnostic);
}
}

static void unsigned_width(unsigned Width, uint64_t Value,
std::string Description, const MCFixup &Fixup,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
if (!isUIntN(Width, Value)) {
std::string Diagnostic = "out of range " + Description;

Expand All @@ -65,17 +58,13 @@ static void unsigned_width(unsigned Width, uint64_t Value,
Diagnostic +=
" (expected an integer in the range 0 to " + std::to_string(Max) + ")";

if (Ctx) {
Ctx->reportError(Fixup.getLoc(), Diagnostic);
} else {
llvm_unreachable(Diagnostic.c_str());
}
Ctx->reportError(Fixup.getLoc(), Diagnostic);
}
}

/// Adjusts the value of a branch target before fixup application.
static void adjustBranch(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
// We have one extra bit of precision because the value is rightshifted by
// one.
unsigned_width(Size + 1, Value, std::string("branch target"), Fixup, Ctx);
Expand All @@ -86,13 +75,28 @@ static void adjustBranch(unsigned Size, const MCFixup &Fixup, uint64_t &Value,

/// Adjusts the value of a relative branch target before fixup application.
static void adjustRelativeBranch(unsigned Size, const MCFixup &Fixup,
uint64_t &Value, MCContext *Ctx = nullptr) {
uint64_t &Value, MCContext *Ctx) {
// Jumps are relative to the current instruction.
Value -= 2;

// We have one extra bit of precision because the value is rightshifted by
// one.
signed_width(Size + 1, Value, std::string("branch target"), Fixup, Ctx);
Size += 1;

if (!isIntN(Size, Value) &&
Ctx->getSubtargetInfo()->hasFeature(AVR::FeatureWrappingRjmp)) {
int32_t FlashSize = 0x2000;
int32_t SignedValue = Value;

uint64_t WrappedValue = SignedValue > 0 ? (uint64_t)(Value - FlashSize)
: (uint64_t)(FlashSize + Value);

if (isIntN(Size, WrappedValue)) {
Value = WrappedValue;
}
}

signed_width(Size, Value, std::string("branch target"), Fixup, Ctx);

// Rightshifts the value by one.
AVR::fixups::adjustBranchTarget(Value);
Expand All @@ -105,7 +109,7 @@ static void adjustRelativeBranch(unsigned Size, const MCFixup &Fixup,
///
/// Offset of 0 (so the result is left shifted by 3 bits before application).
static void fixup_call(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
adjustBranch(Size, Fixup, Value, Ctx);

auto top = Value & (0xf00000 << 6); // the top four bits
Expand All @@ -121,7 +125,7 @@ static void fixup_call(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
/// 0000 00kk kkkk k000
/// Offset of 0 (so the result is left shifted by 3 bits before application).
static void fixup_7_pcrel(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
adjustRelativeBranch(Size, Fixup, Value, Ctx);

// Because the value may be negative, we must mask out the sign bits
Expand All @@ -135,7 +139,7 @@ static void fixup_7_pcrel(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
/// 0000 kkkk kkkk kkkk
/// Offset of 0 (so the result isn't left-shifted before application).
static void fixup_13_pcrel(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
adjustRelativeBranch(Size, Fixup, Value, Ctx);

// Because the value may be negative, we must mask out the sign bits
Expand All @@ -147,8 +151,7 @@ static void fixup_13_pcrel(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
///
/// Resolves to:
/// 10q0 qq10 0000 1qqq
static void fixup_6(const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
static void fixup_6(const MCFixup &Fixup, uint64_t &Value, MCContext *Ctx) {
unsigned_width(6, Value, std::string("immediate"), Fixup, Ctx);

Value = ((Value & 0x20) << 8) | ((Value & 0x18) << 7) | (Value & 0x07);
Expand All @@ -160,7 +163,7 @@ static void fixup_6(const MCFixup &Fixup, uint64_t &Value,
/// Resolves to:
/// 0000 0000 kk00 kkkk
static void fixup_6_adiw(const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
unsigned_width(6, Value, std::string("immediate"), Fixup, Ctx);

Value = ((Value & 0x30) << 2) | (Value & 0x0f);
Expand All @@ -170,8 +173,7 @@ static void fixup_6_adiw(const MCFixup &Fixup, uint64_t &Value,
///
/// Resolves to:
/// 0000 0000 AAAA A000
static void fixup_port5(const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
static void fixup_port5(const MCFixup &Fixup, uint64_t &Value, MCContext *Ctx) {
unsigned_width(5, Value, std::string("port number"), Fixup, Ctx);

Value &= 0x1f;
Expand All @@ -183,8 +185,7 @@ static void fixup_port5(const MCFixup &Fixup, uint64_t &Value,
///
/// Resolves to:
/// 1011 0AAd dddd AAAA
static void fixup_port6(const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
static void fixup_port6(const MCFixup &Fixup, uint64_t &Value, MCContext *Ctx) {
unsigned_width(6, Value, std::string("port number"), Fixup, Ctx);

Value = ((Value & 0x30) << 5) | (Value & 0x0f);
Expand All @@ -195,7 +196,7 @@ static void fixup_port6(const MCFixup &Fixup, uint64_t &Value,
/// Resolves to:
/// 1010 ikkk dddd kkkk
static void fixup_lds_sts_16(const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
unsigned_width(7, Value, std::string("immediate"), Fixup, Ctx);
Value = ((Value & 0x70) << 8) | (Value & 0x0f);
}
Expand All @@ -213,7 +214,7 @@ namespace ldi {
/// 0000 KKKK 0000 KKKK
/// Offset of 0 (so the result isn't left-shifted before application).
static void fixup(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
uint64_t upper = Value & 0xf0;
uint64_t lower = Value & 0x0f;

Expand All @@ -223,25 +224,25 @@ static void fixup(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
static void neg(uint64_t &Value) { Value *= -1; }

static void lo8(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
Value &= 0xff;
ldi::fixup(Size, Fixup, Value, Ctx);
}

static void hi8(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
Value = (Value & 0xff00) >> 8;
ldi::fixup(Size, Fixup, Value, Ctx);
}

static void hh8(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
Value = (Value & 0xff0000) >> 16;
ldi::fixup(Size, Fixup, Value, Ctx);
}

static void ms8(unsigned Size, const MCFixup &Fixup, uint64_t &Value,
MCContext *Ctx = nullptr) {
MCContext *Ctx) {
Value = (Value & 0xff000000) >> 24;
ldi::fixup(Size, Fixup, Value, Ctx);
}
Expand Down
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