Support SFrame command-line and .cfi_section syntax #149935
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This PR adds support for the llvm-mc command-line flag "--gsframe" and adds ".sframe" to the legal values passed ".cfi_section". It plumbs the option through the cfi handling code a fair amount. Code to support actual section generation follows in a future PR. These options match the gnu-assembler's support syntax for sframes, on both the command line and in assembly files. First in a series of changes that will allow llvm-mc to produce sframe .cfi sections. For more information about sframes, see https://sourceware.org/binutils/docs-2.44/sframe-spec.html and the llvm-RFC here: https://discourse.llvm.org/t/rfc-adding-sframe-support-to-llvm/86900
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@llvm/pr-subscribers-mc @llvm/pr-subscribers-debuginfo Author: None (Sterling-Augustine) ChangesThis PR adds support for the llvm-mc command-line flag "--gsframe" and adds ".sframe" to the legal values passed ".cfi_section". It plumbs the option through the cfi handling code a fair amount. Code to support actual section generation follows in a future PR. These options match the gnu-assembler's support syntax for sframes, on both the command line and in assembly files. First in a series of changes that will allow llvm-mc to produce sframe .cfi sections. For more information about sframes, see https://sourceware.org/binutils/docs-2.44/sframe-spec.html and the llvm-RFC here: Full diff: https://github.com/llvm/llvm-project/pull/149935.diff 13 Files Affected:
diff --git a/llvm/include/llvm/MC/MCObjectStreamer.h b/llvm/include/llvm/MC/MCObjectStreamer.h
index 2ceeba22abccd..aea93e9dc7e4f 100644
--- a/llvm/include/llvm/MC/MCObjectStreamer.h
+++ b/llvm/include/llvm/MC/MCObjectStreamer.h
@@ -40,6 +40,7 @@ class MCObjectStreamer : public MCStreamer {
std::unique_ptr<MCAssembler> Assembler;
bool EmitEHFrame;
bool EmitDebugFrame;
+ bool EmitSFrame;
struct PendingAssignment {
MCSymbol *Symbol;
@@ -70,7 +71,7 @@ class MCObjectStreamer : public MCStreamer {
void emitFrames(MCAsmBackend *MAB);
MCSymbol *emitCFILabel() override;
- void emitCFISections(bool EH, bool Debug) override;
+ void emitCFISections(bool EH, bool Debug, bool SFrame) override;
public:
void visitUsedSymbol(const MCSymbol &Sym) override;
diff --git a/llvm/include/llvm/MC/MCStreamer.h b/llvm/include/llvm/MC/MCStreamer.h
index 4bfc8f921ef11..dfaf3487e11a7 100644
--- a/llvm/include/llvm/MC/MCStreamer.h
+++ b/llvm/include/llvm/MC/MCStreamer.h
@@ -986,7 +986,7 @@ class LLVM_ABI MCStreamer {
const MCSymbol *Lo);
virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID);
- virtual void emitCFISections(bool EH, bool Debug);
+ virtual void emitCFISections(bool EH, bool Debug, bool SFrame);
void emitCFIStartProc(bool IsSimple, SMLoc Loc = SMLoc());
void emitCFIEndProc();
virtual void emitCFIDefCfa(int64_t Register, int64_t Offset, SMLoc Loc = {});
diff --git a/llvm/include/llvm/MC/MCTargetOptions.h b/llvm/include/llvm/MC/MCTargetOptions.h
index d95adf92b9a83..235d58d585b40 100644
--- a/llvm/include/llvm/MC/MCTargetOptions.h
+++ b/llvm/include/llvm/MC/MCTargetOptions.h
@@ -102,6 +102,9 @@ class MCTargetOptions {
// functions on Darwins.
bool EmitCompactUnwindNonCanonical : 1;
+ // Whether to emit SFrame unwind sections.
+ bool EmitSFrameUnwind : 1;
+
// Whether or not to use full register names on PowerPC.
bool PPCUseFullRegisterNames : 1;
diff --git a/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h b/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h
index b057effd88128..adfdccdb5ab77 100644
--- a/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h
+++ b/llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h
@@ -40,6 +40,8 @@ LLVM_ABI EmitDwarfUnwindType getEmitDwarfUnwind();
LLVM_ABI bool getEmitCompactUnwindNonCanonical();
+LLVM_ABI bool getEmitSFrameUnwind();
+
LLVM_ABI bool getShowMCInst();
LLVM_ABI bool getFatalWarnings();
diff --git a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
index de6ebcf0c3419..51342c6b91345 100644
--- a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
@@ -39,7 +39,7 @@ void ARMException::beginFunction(const MachineFunction *MF) {
if (CFISecType == AsmPrinter::CFISection::Debug) {
if (!hasEmittedCFISections) {
if (Asm->getModuleCFISectionType() == AsmPrinter::CFISection::Debug)
- Asm->OutStreamer->emitCFISections(false, true);
+ Asm->OutStreamer->emitCFISections(false, true, false);
hasEmittedCFISections = true;
}
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index 4fac4bbc98477..6b8d08cb201d6 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -109,9 +109,11 @@ void DwarfCFIException::beginBasicBlockSection(const MachineBasicBlock &MBB) {
// chose not to be verbose in that case. And with `ForceDwarfFrameSection`,
// we should always emit .debug_frame.
if (CFISecType == AsmPrinter::CFISection::Debug ||
- Asm->TM.Options.ForceDwarfFrameSection)
+ Asm->TM.Options.ForceDwarfFrameSection ||
+ Asm->TM.Options.MCOptions.EmitSFrameUnwind)
Asm->OutStreamer->emitCFISections(
- CFISecType == AsmPrinter::CFISection::EH, true);
+ CFISecType == AsmPrinter::CFISection::EH, true,
+ Asm->TM.Options.MCOptions.EmitSFrameUnwind);
hasEmittedCFISections = true;
}
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 67c53e01a6111..7119ef4a2bbcd 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -345,7 +345,7 @@ class MCAsmStreamer final : public MCStreamer {
void emitIdent(StringRef IdentString) override;
void emitCFIBKeyFrame() override;
void emitCFIMTETaggedFrame() override;
- void emitCFISections(bool EH, bool Debug) override;
+ void emitCFISections(bool EH, bool Debug, bool SFrame) override;
void emitCFIDefCfa(int64_t Register, int64_t Offset, SMLoc Loc) override;
void emitCFIDefCfaOffset(int64_t Offset, SMLoc Loc) override;
void emitCFIDefCfaRegister(int64_t Register, SMLoc Loc) override;
@@ -1906,15 +1906,24 @@ void MCAsmStreamer::emitIdent(StringRef IdentString) {
EmitEOL();
}
-void MCAsmStreamer::emitCFISections(bool EH, bool Debug) {
- MCStreamer::emitCFISections(EH, Debug);
+void MCAsmStreamer::emitCFISections(bool EH, bool Debug, bool SFrame) {
+ MCStreamer::emitCFISections(EH, Debug, SFrame);
OS << "\t.cfi_sections ";
+ bool C = false;
if (EH) {
OS << ".eh_frame";
- if (Debug)
- OS << ", .debug_frame";
- } else if (Debug) {
+ C = true;
+ }
+ if (Debug) {
+ if (C)
+ OS << ", ";
OS << ".debug_frame";
+ C = true;
+ }
+ if (SFrame) {
+ if (C)
+ OS << ", ";
+ OS << ".sframe";
}
EmitEOL();
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 42f4cf49d7f38..d7f4be1bfb573 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -130,10 +130,11 @@ void MCObjectStreamer::visitUsedSymbol(const MCSymbol &Sym) {
Assembler->registerSymbol(Sym);
}
-void MCObjectStreamer::emitCFISections(bool EH, bool Debug) {
- MCStreamer::emitCFISections(EH, Debug);
+void MCObjectStreamer::emitCFISections(bool EH, bool Debug, bool SFrame) {
+ MCStreamer::emitCFISections(EH, Debug, SFrame);
EmitEHFrame = EH;
EmitDebugFrame = Debug;
+ EmitSFrame = SFrame;
}
void MCObjectStreamer::emitValueImpl(const MCExpr *Value, unsigned Size,
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index d0b6ea4cfd562..eda5e8c37f7b8 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -4093,27 +4093,30 @@ bool AsmParser::parseDirectiveCVFPOData() {
}
/// parseDirectiveCFISections
-/// ::= .cfi_sections section [, section]
+/// ::= .cfi_sections section [, section][, section]
bool AsmParser::parseDirectiveCFISections() {
StringRef Name;
bool EH = false;
bool Debug = false;
+ bool SFrame = false;
if (!parseOptionalToken(AsmToken::EndOfStatement)) {
for (;;) {
if (parseIdentifier(Name))
- return TokError("expected .eh_frame or .debug_frame");
+ return TokError("expected .eh_frame, .debug_frame, or .sframe");
if (Name == ".eh_frame")
EH = true;
else if (Name == ".debug_frame")
Debug = true;
+ else if (Name == ".sframe")
+ SFrame = true;
if (parseOptionalToken(AsmToken::EndOfStatement))
break;
if (parseComma())
return true;
}
}
- getStreamer().emitCFISections(EH, Debug);
+ getStreamer().emitCFISections(EH, Debug, SFrame);
return false;
}
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 30198c97d8ab9..e14a32f5dc0ce 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -415,7 +415,7 @@ void MCStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
void MCStreamer::emitConditionalAssignment(MCSymbol *Symbol,
const MCExpr *Value) {}
-void MCStreamer::emitCFISections(bool EH, bool Debug) {}
+void MCStreamer::emitCFISections(bool EH, bool Debug, bool SFrame) {}
void MCStreamer::emitCFIStartProc(bool IsSimple, SMLoc Loc) {
if (!FrameInfoStack.empty() &&
diff --git a/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp b/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp
index 2adc29172f9dd..ff95ff78fd53a 100644
--- a/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp
+++ b/llvm/lib/MC/MCTargetOptionsCommandFlags.cpp
@@ -41,6 +41,7 @@ MCOPT(int, DwarfVersion)
MCOPT(bool, Dwarf64)
MCOPT(EmitDwarfUnwindType, EmitDwarfUnwind)
MCOPT(bool, EmitCompactUnwindNonCanonical)
+MCOPT(bool, EmitSFrameUnwind)
MCOPT(bool, ShowMCInst)
MCOPT(bool, FatalWarnings)
MCOPT(bool, NoWarn)
@@ -105,6 +106,11 @@ llvm::mc::RegisterMCTargetOptionsFlags::RegisterMCTargetOptionsFlags() {
false)); // By default, use DWARF for non-canonical personalities.
MCBINDOPT(EmitCompactUnwindNonCanonical);
+ static cl::opt<bool> EmitSFrameUnwind(
+ "gsframe", cl::desc("Whether to emit .sframe unwind sections."),
+ cl::init(false));
+ MCBINDOPT(EmitSFrameUnwind);
+
static cl::opt<bool> ShowMCInst(
"asm-show-inst",
cl::desc("Emit internal instruction representation to assembly file"));
@@ -188,6 +194,7 @@ MCTargetOptions llvm::mc::InitMCTargetOptionsFromFlags() {
Options.X86Sse2Avx = getX86Sse2Avx();
Options.EmitDwarfUnwind = getEmitDwarfUnwind();
Options.EmitCompactUnwindNonCanonical = getEmitCompactUnwindNonCanonical();
+ Options.EmitSFrameUnwind = getEmitSFrameUnwind();
Options.AsSecureLogFile = getAsSecureLogFile();
return Options;
diff --git a/llvm/test/MC/ELF/AArch64/cfi.s b/llvm/test/MC/ELF/AArch64/cfi.s
index 6bdf03cc7bb85..7047f92bab8fe 100644
--- a/llvm/test/MC/ELF/AArch64/cfi.s
+++ b/llvm/test/MC/ELF/AArch64/cfi.s
@@ -557,12 +557,14 @@ f37:
// CHECK-NEXT: }
.ifdef ERR
-// ERR: [[#@LINE+1]]:15: error: expected .eh_frame or .debug_frame
+// ERR: [[#@LINE+1]]:15: error: expected .eh_frame, .debug_frame, or .sframe
.cfi_sections $
// ERR: [[#@LINE+1]]:28: error: expected comma
.cfi_sections .debug_frame $
// ERR: [[#@LINE+1]]:39: error: expected comma
.cfi_sections .debug_frame, .eh_frame $
+// ERR: [[#@LINE+1]]:48: error: expected comma
+.cfi_sections .debug_frame, .eh_frame, .sframe $
// ERR: [[#@LINE+1]]:16: error: unexpected token
.cfi_startproc $
diff --git a/llvm/test/MC/ELF/cfi.s b/llvm/test/MC/ELF/cfi.s
index 3bd16aec4613e..b7f937104dbf2 100644
--- a/llvm/test/MC/ELF/cfi.s
+++ b/llvm/test/MC/ELF/cfi.s
@@ -445,12 +445,14 @@ f37:
// CHECK: }
.ifdef ERR
-// ERR: [[#@LINE+1]]:15: error: expected .eh_frame or .debug_frame
+// ERR: [[#@LINE+1]]:15: error: expected .eh_frame, .debug_frame, or .sframe
.cfi_sections $
// ERR: [[#@LINE+1]]:28: error: expected comma
.cfi_sections .debug_frame $
// ERR: [[#@LINE+1]]:39: error: expected comma
.cfi_sections .debug_frame, .eh_frame $
+// ERR: [[#@LINE+1]]:48: error: expected comma
+.cfi_sections .debug_frame, .eh_frame, .sframe $
// ERR: [[#@LINE+1]]:16: error: unexpected token
.cfi_startproc $
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lenary
approved these changes
Jul 22, 2025
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/31033 Here is the relevant piece of the build log for the reference |
Sterling-Augustine
added a commit
that referenced
this pull request
Jul 23, 2025
This reverts commit f9d0bd0.
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Hi @Sterling-Augustine, I see you made a revert commit, do you plan to apply that change? Or are you still investigating the failure? |
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I cannot reproduce the failure. The test works fine locally with ninja check-clang-driver and the log is clean. Please advise. |
Did you try with the PS4 target as the default triple? |
|
This bot is also failing on that test but just targets a native linux target: https://lab.llvm.org/buildbot/#/builders/174/builds/21595 |
|
We're seeing this happen consistently on builds w/o assertions or backtraces. I've only seen it pop up once on an asserts enabled builds. |
Sterling-Augustine
added a commit
that referenced
this pull request
Jul 23, 2025
|
Revert is merged. Still haven't managed to reproduce this. |
You can try the cmake commands used by each of the bots: |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/39126 Here is the relevant piece of the build log for the reference |
|
Never did manage to reproduce this, but I did find a single uninitialized bit (asan does't check bitfields), which I'm guessing is the source of the trouble. Reapplied with that fix in 29e8599 If the failure reappears, just immediately revert and I'll dig deeper. |
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Jul 28, 2025
This PR adds support for the llvm-mc command-line flag "--gsframe" and adds ".sframe" to the legal values passed ".cfi_section". It plumbs the option through the cfi handling code a fair amount. Code to support actual section generation follows in a future PR. These options match the gnu-assembler's support syntax for sframes, on both the command line and in assembly files. First in a series of changes that will allow llvm-mc to produce sframe .cfi sections. For more information about sframes, see https://sourceware.org/binutils/docs-2.44/sframe-spec.html and the llvm-RFC here: https://discourse.llvm.org/t/rfc-adding-sframe-support-to-llvm/86900
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Jul 28, 2025
)" (llvm#150316) This reverts commit f9d0bd0.
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This PR adds support for the llvm-mc command-line flag "--gsframe" and adds ".sframe" to the legal values passed ".cfi_section". It plumbs the option through the cfi handling code a fair amount. Code to support actual section generation follows in a future PR.
These options match the gnu-assembler's support syntax for sframes, on both the command line and in assembly files.
First in a series of changes that will allow llvm-mc to produce sframe .cfi sections. For more information about sframes, see https://sourceware.org/binutils/docs-2.44/sframe-spec.html
and the llvm-RFC here:
https://discourse.llvm.org/t/rfc-adding-sframe-support-to-llvm/86900