https://github.com/MaskRay created
https://github.com/llvm/llvm-project/pull/183472
Wire the llvm-mc --reloc-section-sym={all,internal,none} option through
the clang driver (-Wa,--reloc-section-sym=) and cc1as
(--reloc-section-sym=). The option is only valid for ELF targets.
GNU Assembler will add the option as well.
>From ee06072de5e5f8516c09385b272328b75d3d5da7 Mon Sep 17 00:00:00 2001
From: Fangrui Song <[email protected]>
Date: Wed, 25 Feb 2026 23:53:41 -0800
Subject: [PATCH] [Driver] Add -Wa,--reloc-section-sym= to control section
symbol conversion
Wire the llvm-mc --reloc-section-sym={all,internal,none} option through
the clang driver (-Wa,--reloc-section-sym=) and cc1as
(--reloc-section-sym=). The option is only valid for ELF targets.
GNU Assembler will add the option as well.
---
clang/include/clang/Basic/CodeGenOptions.def | 2 ++
clang/include/clang/Basic/CodeGenOptions.h | 2 ++
clang/include/clang/Options/Options.td | 6 +++++
clang/lib/CodeGen/BackendUtil.cpp | 1 +
clang/lib/Driver/ToolChains/Clang.cpp | 16 ++++++++++++
clang/test/Driver/reloc-section-sym.c | 9 +++++++
clang/test/Misc/cc1as-reloc-section-sym.s | 27 ++++++++++++++++++++
clang/tools/driver/cc1as_main.cpp | 9 +++++++
8 files changed, 72 insertions(+)
create mode 100644 clang/test/Driver/reloc-section-sym.c
create mode 100644 clang/test/Misc/cc1as-reloc-section-sym.s
diff --git a/clang/include/clang/Basic/CodeGenOptions.def
b/clang/include/clang/Basic/CodeGenOptions.def
index 5e174b21be466..3d8db87a185b4 100644
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -29,6 +29,8 @@ CODEGENOPT(Name, Bits, Default, Compatibility)
CODEGENOPT(DisableIntegratedAS, 1, 0, Benign) ///< -no-integrated-as
CODEGENOPT(Crel, 1, 0, Benign) ///< -Wa,--crel
+ENUM_CODEGENOPT(RelocSectionSym, RelocSectionSymType, 2,
+ RelocSectionSymType::All, Benign) ///< -Wa,--reloc-section-sym=
CODEGENOPT(ImplicitMapSyms, 1, 0, Benign) ///< -Wa,-mmapsyms=implicit
CODEGENOPT(AsmVerbose , 1, 0, Benign) ///< -dA, -fverbose-asm.
CODEGENOPT(PreserveAsmComments, 1, 1, Benign) ///< -dA,
-fno-preserve-as-comments.
diff --git a/clang/include/clang/Basic/CodeGenOptions.h
b/clang/include/clang/Basic/CodeGenOptions.h
index 8ef0d87faaeaf..9454f7672b7e1 100644
--- a/clang/include/clang/Basic/CodeGenOptions.h
+++ b/clang/include/clang/Basic/CodeGenOptions.h
@@ -20,6 +20,7 @@
#include "llvm/ADT/FloatingPointMode.h"
#include "llvm/Frontend/Debug/Options.h"
#include "llvm/Frontend/Driver/CodeGenOptions.h"
+#include "llvm/MC/MCTargetOptions.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/Hash.h"
#include "llvm/Support/Regex.h"
@@ -72,6 +73,7 @@ class CodeGenOptionsBase {
using DebugTemplateNamesKind = llvm::codegenoptions::DebugTemplateNamesKind;
using DebugInfoKind = llvm::codegenoptions::DebugInfoKind;
using DebuggerKind = llvm::DebuggerKind;
+ using RelocSectionSymType = llvm::RelocSectionSymType;
#define CODEGENOPT(Name, Bits, Default, Compatibility) unsigned Name : Bits;
#define ENUM_CODEGENOPT(Name, Type, Bits, Default, Compatibility)
diff --git a/clang/include/clang/Options/Options.td
b/clang/include/clang/Options/Options.td
index c8a1e478122e1..09b6f79d1889a 100644
--- a/clang/include/clang/Options/Options.td
+++ b/clang/include/clang/Options/Options.td
@@ -7987,6 +7987,12 @@ def massembler_fatal_warnings : Flag<["-"],
"massembler-fatal-warnings">,
def crel : Flag<["--"], "crel">,
HelpText<"Enable CREL relocation format (ELF only)">,
MarshallingInfoFlag<CodeGenOpts<"Crel">>;
+def reloc_section_sym : Joined<["--"], "reloc-section-sym=">,
+ HelpText<"Section symbol conversion for relocations: all, internal, none
(ELF only)">,
+ Values<"all,internal,none">,
+ NormalizedValuesScope<"llvm::RelocSectionSymType">,
+ NormalizedValues<["All", "Internal", "None"]>,
+ MarshallingInfoEnum<CodeGenOpts<"RelocSectionSym">, "All">;
// The leading 'g' is misleading. This is an unwind tables option, not
// a debug option. But uses this name for gnu compatibility.
def gsframe : Flag<["--"], "gsframe">,
diff --git a/clang/lib/CodeGen/BackendUtil.cpp
b/clang/lib/CodeGen/BackendUtil.cpp
index 94257fb96fc7f..82396d44a35b1 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -503,6 +503,7 @@ static bool initTargetOptions(const CompilerInstance &CI,
Options.MCOptions.Dwarf64 = CodeGenOpts.Dwarf64;
Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
Options.MCOptions.Crel = CodeGenOpts.Crel;
+ Options.MCOptions.RelocSectionSym = CodeGenOpts.getRelocSectionSym();
Options.MCOptions.ImplicitMapSyms = CodeGenOpts.ImplicitMapSyms;
Options.MCOptions.X86RelaxRelocations = CodeGenOpts.X86RelaxRelocations;
Options.MCOptions.CompressDebugSections =
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp
b/clang/lib/Driver/ToolChains/Clang.cpp
index 0aa93e2e46814..33af2d3ed3db5 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2436,6 +2436,7 @@ static void CollectArgsForIntegratedAssembler(Compilation
&C,
const llvm::Triple &Triple = C.getDefaultToolChain().getTriple();
bool IsELF = Triple.isOSBinFormatELF();
bool Crel = false, ExperimentalCrel = false;
+ StringRef RelocSectionSym;
bool SFrame = false, ExperimentalSFrame = false;
bool ImplicitMapSyms = false;
bool UseRelaxRelocations = C.getDefaultToolChain().useRelaxRelocations();
@@ -2636,6 +2637,8 @@ static void CollectArgsForIntegratedAssembler(Compilation
&C,
Crel = false;
} else if (Value == "--allow-experimental-crel") {
ExperimentalCrel = true;
+ } else if (Value.starts_with("--reloc-section-sym=")) {
+ RelocSectionSym = Value.substr(strlen("--reloc-section-sym="));
} else if (Value.starts_with("-I")) {
CmdArgs.push_back(Value.data());
// We need to consume the next argument if the current arg is a plain
@@ -2709,6 +2712,19 @@ static void
CollectArgsForIntegratedAssembler(Compilation &C,
<< "-Wa,--crel" << D.getTargetTriple();
}
}
+ if (!RelocSectionSym.empty()) {
+ if (RelocSectionSym != "all" && RelocSectionSym != "internal" &&
+ RelocSectionSym != "none")
+ D.Diag(diag::err_drv_invalid_value)
+ << ("-Wa,--reloc-section-sym=" + RelocSectionSym).str()
+ << RelocSectionSym;
+ else if (Triple.isOSBinFormatELF())
+ CmdArgs.push_back(
+ Args.MakeArgString("--reloc-section-sym=" + RelocSectionSym));
+ else
+ D.Diag(diag::err_drv_unsupported_opt_for_target)
+ << "-Wa,--reloc-section-sym" << D.getTargetTriple();
+ }
if (SFrame) {
if (Triple.isOSBinFormatELF() && Triple.isX86()) {
if (!ExperimentalSFrame)
diff --git a/clang/test/Driver/reloc-section-sym.c
b/clang/test/Driver/reloc-section-sym.c
new file mode 100644
index 0000000000000..a11dab9178157
--- /dev/null
+++ b/clang/test/Driver/reloc-section-sym.c
@@ -0,0 +1,9 @@
+// RUN: %clang -### -c --target=x86_64 -Wa,--reloc-section-sym=internal %s
-Werror 2>&1 | FileCheck %s
+// RUN: %clang -### -c --target=aarch64
-Wa,--reloc-section-sym=internal,--reloc-section-sym=none %s -Werror 2>&1 |
FileCheck %s --check-prefix=NONE
+// RUN: not %clang -### -c --target=arm64-apple-darwin
-Wa,--reloc-section-sym=internal %s 2>&1 | FileCheck %s --check-prefix=ERR
+// RUN: not %clang -### -c --target=x86_64 -Wa,--reloc-section-sym=x %s 2>&1 |
FileCheck %s --check-prefix=BADVAL
+
+// CHECK: "--reloc-section-sym=internal"
+// NONE: "--reloc-section-sym=none"
+// ERR: error: unsupported option '-Wa,--reloc-section-sym' for target
+// BADVAL: error: invalid value 'x' in '-Wa,--reloc-section-sym=x'
diff --git a/clang/test/Misc/cc1as-reloc-section-sym.s
b/clang/test/Misc/cc1as-reloc-section-sym.s
new file mode 100644
index 0000000000000..e96cd1ac23b19
--- /dev/null
+++ b/clang/test/Misc/cc1as-reloc-section-sym.s
@@ -0,0 +1,27 @@
+// REQUIRES: x86-registered-target
+/// cc1as option for --reloc-section-sym. See
llvm/test/MC/ELF/reloc-section-sym.s
+
+// RUN: %clang -cc1as -triple x86_64 %s -filetype obj -o %t.default.o
+// RUN: %clang -cc1as -triple x86_64 %s -filetype obj
--reloc-section-sym=internal -o %t.internal.o
+// RUN: %clang -cc1as -triple x86_64 %s -filetype obj --reloc-section-sym=none
-o %t.none.o
+// RUN: llvm-readelf -rs %t.default.o | FileCheck %s --check-prefix=DEFAULT
+// RUN: llvm-readelf -rs %t.internal.o | FileCheck %s --check-prefix=INTERNAL
+// RUN: llvm-readelf -rs %t.none.o | FileCheck %s --check-prefix=NONE
+
+.text
+ nop
+local:
+ nop
+.Ltemp:
+ nop
+
+.section .text1,"ax"
+ call local
+ call .Ltemp
+
+// DEFAULT: R_X86_64_PLT32 {{.*}} .text - 3
+// DEFAULT-NEXT: R_X86_64_PLT32 {{.*}} .text - 2
+// INTERNAL: R_X86_64_PLT32 {{.*}} local - 4
+// INTERNAL-NEXT: R_X86_64_PLT32 {{.*}} .text - 2
+// NONE: R_X86_64_PLT32 {{.*}} local - 4
+// NONE-NEXT: R_X86_64_PLT32 {{.*}} .Ltemp - 4
diff --git a/clang/tools/driver/cc1as_main.cpp
b/clang/tools/driver/cc1as_main.cpp
index ccc48a77891d7..c6cdd46a41f37 100644
--- a/clang/tools/driver/cc1as_main.cpp
+++ b/clang/tools/driver/cc1as_main.cpp
@@ -177,6 +177,8 @@ struct AssemblerInvocation {
LLVM_PREFERRED_TYPE(bool)
unsigned X86Sse2Avx : 1;
+ RelocSectionSymType RelocSectionSym = RelocSectionSymType::All;
+
/// The name of the relocation model to use.
std::string RelocationModel;
@@ -394,6 +396,12 @@ bool
AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
Args.hasArg(OPT_femit_compact_unwind_non_canonical);
Opts.EmitSFrameUnwind = Args.hasArg(OPT_gsframe);
Opts.Crel = Args.hasArg(OPT_crel);
+ Opts.RelocSectionSym = RelocSectionSymType::All;
+ if (auto *A = Args.getLastArg(OPT_reloc_section_sym))
+ Opts.RelocSectionSym = StringSwitch<RelocSectionSymType>(A->getValue())
+ .Case("internal", RelocSectionSymType::Internal)
+ .Case("none", RelocSectionSymType::None)
+ .Default(RelocSectionSymType::All);
Opts.ImplicitMapsyms = Args.hasArg(OPT_mmapsyms_implicit);
Opts.X86RelaxRelocations = !Args.hasArg(OPT_mrelax_relocations_no);
Opts.X86Sse2Avx = Args.hasArg(OPT_msse2avx);
@@ -461,6 +469,7 @@ static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
MCOptions.EmitSFrameUnwind = Opts.EmitSFrameUnwind;
MCOptions.MCSaveTempLabels = Opts.SaveTemporaryLabels;
MCOptions.Crel = Opts.Crel;
+ MCOptions.RelocSectionSym = Opts.RelocSectionSym;
MCOptions.ImplicitMapSyms = Opts.ImplicitMapsyms;
MCOptions.X86RelaxRelocations = Opts.X86RelaxRelocations;
MCOptions.X86Sse2Avx = Opts.X86Sse2Avx;
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