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[RISCV][NFC] Refactor doRelaxationQCCall #231

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[RISCV][NFC] Refactor doRelaxationQCCall #231

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69 changes: 42 additions & 27 deletions lib/Target/RISCV/RISCVLDBackend.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -299,9 +299,13 @@ bool RISCVLDBackend::doRelaxationCall(Relocation *reloc, bool DoCompressed) {
return true;
}

bool RISCVLDBackend::doRelaxationQCCall(Relocation *reloc, bool DoCompressed) {
// This function performs the relaxation to replace: QC.E.JAL or QC.E.J with
// one of JAL, C.J, or C.JAL.
bool RISCVLDBackend::doRelaxationQCCall(Relocation *reloc) {
/* Four similar relaxations can be applied here, in order of preference:
* -- qc.e.j -> c.j (saves 4 bytes)
* -- qc.e.jal -> c.jal (saves 4 bytes)
* -- qc.e.j -> jal (saves 2 bytes)
* -- qc.e.jal -> jal (saves 2 bytes)
*/

Fragment *frag = reloc->targetRef()->frag();
RegionFragmentEx *region = llvm::dyn_cast<RegionFragmentEx>(frag);
Expand All @@ -318,19 +322,20 @@ bool RISCVLDBackend::doRelaxationQCCall(Relocation *reloc, bool DoCompressed) {
Relocator::DWord P = reloc->place(m_Module);
Relocator::DWord X = S + A - P;

bool canRelaxXqci =
config().targets().is32Bits() && config().options().getRISCVRelaxXqci();
bool canRelax =
config().options().getRISCVRelax() && canRelaxXqci && llvm::isInt<21>(X);
bool canCompress = DoCompressed && llvm::isInt<12>(X);
bool canRelaxXqci = config().options().getRISCVRelax() &&
config().targets().is32Bits() &&
config().options().getRISCVRelaxXqci();

if (!canRelax) {
reportMissedRelaxation("RISCV_QC_E_CALL", *region, offset,
canCompress ? 4 : 2, reloc->symInfo()->name());
return false;
}
// For JAL, the destination must be within 21 bits.
bool canRelaxJAL = canRelaxXqci && llvm::isInt<21>(X);

if (canCompress) {
// For C.J/C.JAL, the destination must be within 12 bits. `QC.E.J` and
// `QC.E.JAL` only have destinations of `x0` and `ra` respectively, which are
// compatible with the compressed forms.
bool canRelaxC_J = canRelaxXqci && config().options().getRISCVRelaxToC() &&
llvm::isInt<12>(X);

if (canRelaxC_J) {
uint32_t compressed = isTailCall ? 0xa001 : 0x2001;
const char *msg = isTailCall ? "RISCV_QC_E_J_C" : "RISCV_QC_E_JAL_C";

Expand All @@ -353,19 +358,29 @@ bool RISCVLDBackend::doRelaxationQCCall(Relocation *reloc, bool DoCompressed) {
return true;
}

// Replace the instruction to JAL
unsigned rd = isTailCall ? /*x0*/ 0 : /*ra*/ 1;
uint32_t jal_instr = 0x6fu | rd << 7;
region->replaceInstruction(offset, reloc, jal_instr, 4);
// Replace the reloc to R_RISCV_JAL
reloc->setType(llvm::ELF::R_RISCV_JAL);
reloc->setTargetData(jal_instr);
// Delete the next instruction
const char *msg = isTailCall ? "RISCV_QC_E_J" : "RISCV_QC_E_JAL";
relaxDeleteBytes(msg, *region, offset + 4, 2,
reloc->symInfo()->name());
if (canRelaxJAL) {
// Replace the instruction to JAL
unsigned rd = isTailCall ? /*x0*/ 0 : /*ra*/ 1;
uint32_t jal_instr = 0x6fu | rd << 7;

return true;
region->replaceInstruction(offset, reloc, jal_instr, 4);
reloc->setTargetData(jal_instr);
reloc->setType(llvm::ELF::R_RISCV_JAL);
const char *msg = isTailCall ? "RISCV_QC_E_J" : "RISCV_QC_E_JAL";
// Delete the next instruction
relaxDeleteBytes(msg, *region, offset + 4, 2, reloc->symInfo()->name());

// Report missed relaxation as `C.J`/`C.JAL` would have been smaller
reportMissedRelaxation("RISCV_QC_E_CALL", *region, offset, 2,
reloc->symInfo()->name());

return true;
}

reportMissedRelaxation("RISCV_QC_E_CALL", *region, offset, 4,
reloc->symInfo()->name());

return false;
}

bool RISCVLDBackend::doRelaxationLui(Relocation *reloc, Relocator::DWord G) {
Expand Down Expand Up @@ -830,7 +845,7 @@ void RISCVLDBackend::mayBeRelax(int relaxation_pass, bool &pFinished) {
}
case ELF::riscv::internal::R_RISCV_QC_E_CALL_PLT: {
if (nextRelax && relaxation_pass == RELAXATION_CALL)
doRelaxationQCCall(relocation, DoCompressed);
doRelaxationQCCall(relocation);
break;
}
}
Expand Down
2 changes: 1 addition & 1 deletion lib/Target/RISCV/RISCVLDBackend.h
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Original file line number Diff line number Diff line change
Expand Up @@ -198,7 +198,7 @@ class RISCVLDBackend : public GNULDBackend {
bool isGOTReloc(Relocation *reloc) const;

bool doRelaxationCall(Relocation *R, bool DoCompressed);
bool doRelaxationQCCall(Relocation *R, bool DoCompressed);
bool doRelaxationQCCall(Relocation *R);

bool doRelaxationLui(Relocation *R, Relocation::DWord G);

Expand Down
28 changes: 22 additions & 6 deletions test/RISCV/standalone/Relaxation/QC_E_CALL_TO_JAL/QC_E_CALL_TO_JAL.test
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Original file line number Diff line number Diff line change
Expand Up @@ -18,11 +18,15 @@ VERBOSE_RELAX_C: RISCV_QC_E_JAL_C : Deleting 4 bytes for symbol 'f' in section .
VERBOSE_RELAX_C: RISCV_QC_E_J_C : relaxing instruction 0x00000000401f to compressed instruction 0xa001 for symbol f in section .text+0x77A file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_J_C : Deleting 4 bytes for symbol 'f' in section .text+0x77c file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_JAL : Deleting 2 bytes for symbol 'f' in section .text+0x874 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x870 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_J : Deleting 2 bytes for symbol 'f' in section .text+0x878 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x874 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_JAL : Deleting 2 bytes for symbol 'f' in section .text+0xffef0 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0xffeec file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_J : Deleting 2 bytes for symbol 'f' in section .text+0xffef4 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x1000e8 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x1000ee file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0xffef0 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 4 bytes for symbol 'f' in section .text+0x1000e8 file {{.*}}.o
VERBOSE_RELAX_C: RISCV_QC_E_CALL : Cannot relax 4 bytes for symbol 'f' in section .text+0x1000ee file {{.*}}.o

RUN: %objdump -d %t.1.out 2>&1 | %filecheck %s --check-prefix=DUMP_RELAX_C
RUN: %objdump -d %t.1.so 2>&1 | %filecheck %s --check-prefix=DUMP_RELAX_C
Expand All @@ -41,27 +45,35 @@ RUN: %filecheck %s --input-file=%t.1.map --check-prefix=MAP_RELAX_C
RUN: %filecheck %s --input-file=%t.1.so.map --check-prefix=MAP_RELAX_C
MAP_RELAX_C: # LinkStats Begin
MAP_RELAX_C: # RelaxationBytesDeleted : 24
MAP_RELAX_C: # RelaxationBytesMissed : 4
MAP_RELAX_C: # RelaxationBytesMissed : 16
MAP_RELAX_C: # LinkStats End

MAP_RELAX_C: .text {{.+}}, Alignment: 0x2, Flags: SHF_ALLOC|SHF_EXECINSTR, Type: SHT_PROGBITS
MAP_RELAX_C: # RelaxationBytesDeleted : 24
MAP_RELAX_C: # RelaxationBytesMissed : 4
MAP_RELAX_C: # RelaxationBytesMissed : 16
MAP_RELAX_C: .text {{.+}}.o #SHT_PROGBITS,SHF_ALLOC|SHF_EXECINSTR,2

# Only non-compressed relaxations are enabled.
RUN: %link %linkopts --relax-xqci --no-relax-c %t.o -o %t.2.out -MapStyle txt -Map %t.2.map --verbose 2>&1 | %filecheck %s --check-prefix=VERBOSE_RELAX
RUN: %link %linkopts --relax-xqci --no-relax-c %t.o -o %t.2.so -shared -MapStyle txt -Map %t.2.so.map --verbose 2>&1 | %filecheck %s --check-prefix=VERBOSE_RELAX
VERBOSE_RELAX: RISCV_QC_E_JAL : Deleting 2 bytes for symbol 'f' in section .text+0x8 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x4 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_J : Deleting 2 bytes for symbol 'f' in section .text+0xc file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x8 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_JAL : Deleting 2 bytes for symbol 'f' in section .text+0x780 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x77c file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_J : Deleting 2 bytes for symbol 'f' in section .text+0x784 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x780 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_JAL : Deleting 2 bytes for symbol 'f' in section .text+0x87c file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x878 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_J : Deleting 2 bytes for symbol 'f' in section .text+0x880 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x87c file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_JAL : Deleting 2 bytes for symbol 'f' in section .text+0xffef8 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0xffef4 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_J : Deleting 2 bytes for symbol 'f' in section .text+0xffefc file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x1000f0 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0x1000f6 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 2 bytes for symbol 'f' in section .text+0xffef8 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 4 bytes for symbol 'f' in section .text+0x1000f0 file {{.*}}.o
VERBOSE_RELAX: RISCV_QC_E_CALL : Cannot relax 4 bytes for symbol 'f' in section .text+0x1000f6 file {{.*}}.o

RUN: %objdump -d %t.2.out 2>&1 | %filecheck %s --check-prefix=DUMP_RELAX
RUN: %objdump -d %t.2.so 2>&1 | %filecheck %s --check-prefix=DUMP_RELAX
Expand All @@ -80,10 +92,12 @@ RUN: %filecheck %s --input-file=%t.2.map --check-prefix=MAP_RELAX
RUN: %filecheck %s --input-file=%t.2.so.map --check-prefix=MAP_RELAX
MAP_RELAX: # LinkStats Begin
MAP_RELAX: # RelaxationBytesDeleted : 16
MAP_RELAX: # RelaxationBytesMissed : 24
MAP_RELAX: # LinkStats End

MAP_RELAX: .text {{.+}}, Alignment: 0x2, Flags: SHF_ALLOC|SHF_EXECINSTR, Type: SHT_PROGBITS
MAP_RELAX: # RelaxationBytesDeleted : 16
MAP_RELAX: # RelaxationBytesMissed : 24
MAP_RELAX: .text {{.+}}.o #SHT_PROGBITS,SHF_ALLOC|SHF_EXECINSTR,2

### Relaxations are disabled.
Expand All @@ -108,9 +122,11 @@ DUMP_NORELAX: qc.e.j
RUN: %filecheck %s --input-file=%t.3.map --check-prefix=MAP_NORELAX
RUN: %filecheck %s --input-file=%t.3.so.map --check-prefix=MAP_NORELAX
MAP_NORELAX: # LinkStats Begin
MAP_NORELAX: # RelaxationBytesMissed : 40
MAP_NORELAX-NOT: # RelaxationBytesDeleted
MAP_NORELAX: # LinkStats End

MAP_NORELAX: .text {{.+}}, Alignment: 0x2, Flags: SHF_ALLOC|SHF_EXECINSTR, Type: SHT_PROGBITS
MAP_NORELAX: # RelaxationBytesMissed : 40
MAP_NORELAX-NOT: # RelaxationBytesDeleted
MAP_NORELAX: .text {{.+}}.o #SHT_PROGBITS,SHF_ALLOC|SHF_EXECINSTR,2
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