[llvm] [clang] [RISCV][MC] Always emit relocations for resolved symbols and relax (PR #73793)
via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 29 05:04:14 PST 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-risc-v
Author: Andreu Carminati (andcarminati)
<details>
<summary>Changes</summary>
If relaxation is not itended, it can be disabled in the linker. Also, we cannot trust Subtarget features here, because it may be empty in case of LTO codegen, preventing relaxations.
Also forward --no-relax option to linker.
---
Full diff: https://github.com/llvm/llvm-project/pull/73793.diff
5 Files Affected:
- (modified) clang/lib/Driver/ToolChains/BareMetal.cpp (+3)
- (modified) clang/lib/Driver/ToolChains/RISCVToolchain.cpp (+3)
- (modified) clang/test/Driver/baremetal.cpp (+10)
- (modified) llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp (+4-8)
- (modified) llvm/test/CodeGen/RISCV/compress.ll (+21-10)
``````````diff
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index 42c8336e626c7b5..fc955d79780e5a0 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -443,6 +443,9 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back("-Bstatic");
+ if (Args.hasArg(options::OPT_mno_relax))
+ CmdArgs.push_back("--no-relax");
+
if (Triple.isARM() || Triple.isThumb()) {
bool IsBigEndian = arm::isARMBigEndian(Triple, Args);
if (IsBigEndian)
diff --git a/clang/lib/Driver/ToolChains/RISCVToolchain.cpp b/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
index 7e6abd144428783..0be7d1a88994957 100644
--- a/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
+++ b/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
@@ -156,6 +156,9 @@ void RISCV::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (!D.SysRoot.empty())
CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+ if (Args.hasArg(options::OPT_mno_relax))
+ CmdArgs.push_back("--no-relax");
+
bool IsRV64 = ToolChain.getArch() == llvm::Triple::riscv64;
CmdArgs.push_back("-m");
if (IsRV64) {
diff --git a/clang/test/Driver/baremetal.cpp b/clang/test/Driver/baremetal.cpp
index c04f4506a0994db..134bf427e3dc160 100644
--- a/clang/test/Driver/baremetal.cpp
+++ b/clang/test/Driver/baremetal.cpp
@@ -460,3 +460,13 @@
// RUN: | FileCheck --check-prefix=CHECK-CLANGRT-ARCH %s
// CHECK-CLANGRT-ARCH: "-lclang_rt.builtins-armv6m"
// CHECK-CLANGRT-ARCH-NOT: "-lclang_rt.builtins"
+
+// RUN: %clang %s -### 2>&1 --target=riscv64-unknown-elf -nostdinc -mno-relax \
+// RUN: --sysroot=%S/Inputs/basic_riscv64_tree/riscv64-unknown-elf \
+// RUN: | FileCheck --check-prefix=CHECK-RV64-NORELAX %s
+// CHECK-RV64-NORELAX: "--no-relax"
+
+// RUN: %clang %s -### 2>&1 --target=riscv64-unknown-elf -nostdinc \
+// RUN: --sysroot=%S/Inputs/basic_riscv64_tree/riscv64-unknown-elf \
+// RUN: | FileCheck --check-prefix=CHECK-RV64-RELAX %s
+// CHECK-RV64-RELAX-NOT: "--no-relax"
\ No newline at end of file
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
index dfc3c9e9908d888..d4efaaf2666e426 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -103,9 +103,9 @@ RISCVAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
return Infos[Kind - FirstTargetFixupKind];
}
-// If linker relaxation is enabled, or the relax option had previously been
-// enabled, always emit relocations even if the fixup can be resolved. This is
-// necessary for correctness as offsets may change during relaxation.
+// Always emit relocations for relative addresses, even if the fixup can be
+// resolved. This is necessary for correctness as offsets may change during
+// relaxation.
bool RISCVAsmBackend::shouldForceRelocation(const MCAssembler &Asm,
const MCFixup &Fixup,
const MCValue &Target) {
@@ -122,13 +122,9 @@ bool RISCVAsmBackend::shouldForceRelocation(const MCAssembler &Asm,
if (Target.isAbsolute())
return false;
break;
- case RISCV::fixup_riscv_got_hi20:
- case RISCV::fixup_riscv_tls_got_hi20:
- case RISCV::fixup_riscv_tls_gd_hi20:
- return true;
}
- return STI.hasFeature(RISCV::FeatureRelax) || ForceRelocs;
+ return true;
}
bool RISCVAsmBackend::fixupNeedsRelaxationAdvanced(const MCFixup &Fixup,
diff --git a/llvm/test/CodeGen/RISCV/compress.ll b/llvm/test/CodeGen/RISCV/compress.ll
index 479b7e524cd347c..fd7c4e9cc9934e9 100644
--- a/llvm/test/CodeGen/RISCV/compress.ll
+++ b/llvm/test/CodeGen/RISCV/compress.ll
@@ -1,3 +1,4 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 3
; This test is designed to run twice, once with function attributes and once
; with target attributes added on the command line.
;
@@ -50,35 +51,45 @@ define i32 @simple_arith(i32 %a, i32 %b) #0 {
define i32 @select(i32 %a, ptr %b) #0 {
; RV32IC-LABEL: <select>:
; RV32IC: c.lw a2, 0(a1)
-; RV32IC-NEXT: c.beqz a2, 0x18
+; RV32IC-NEXT: c.beqz a2, 0x14 <select+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_2>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: c.bnez a2, 0x1e
+; RV32IC-NEXT: c.bnez a2, 0x1a <.LBB1_2+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_4>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: bltu a2, a0, 0x26
+; RV32IC-NEXT: bltu a2, a0, 0x20 <.LBB1_4+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_6>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: bgeu a0, a2, 0x2e
+; RV32IC-NEXT: bgeu a0, a2, 0x28 <.LBB1_6+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_8>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: bltu a0, a2, 0x36
+; RV32IC-NEXT: bltu a0, a2, 0x30 <.LBB1_8+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_10>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: bgeu a2, a0, 0x3e
+; RV32IC-NEXT: bgeu a2, a0, 0x38 <.LBB1_10+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_12>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: blt a2, a0, 0x46
+; RV32IC-NEXT: blt a2, a0, 0x40 <.LBB1_12+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_14>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: bge a0, a2, 0x4e
+; RV32IC-NEXT: bge a0, a2, 0x48 <.LBB1_14+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_16>:
; RV32IC-NEXT: c.lw a2, 0(a1)
-; RV32IC-NEXT: blt a0, a2, 0x56
+; RV32IC-NEXT: blt a0, a2, 0x50 <.LBB1_16+0x2>
; RV32IC-NEXT: c.mv a0, a2
+; RV32IC-LABEL: <.LBB1_18>:
; RV32IC-NEXT: c.lw a1, 0(a1)
-; RV32IC-NEXT: bge a1, a0, 0x5e
+; RV32IC-NEXT: bge a1, a0, 0x58 <.LBB1_18+0x2>
; RV32IC-NEXT: c.mv a0, a1
+; RV32IC-LABEL: <.LBB1_20>:
; RV32IC-NEXT: c.jr ra
%val1 = load volatile i32, ptr %b
%tst1 = icmp eq i32 0, %val1
``````````
</details>
https://github.com/llvm/llvm-project/pull/73793
More information about the cfe-commits
mailing list