[llvm] 04dc687 - [DebugInfo][ARM] Fix incorrect debug information for RWPI accessed globals
Alexandros Lamprineas via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 18 13:29:54 PDT 2021
Author: Alexandros Lamprineas
Date: 2021-10-18T21:29:46+01:00
New Revision: 04dc68710ad2b30a1d3b4a2ca33005af2c9460eb
URL: https://github.com/llvm/llvm-project/commit/04dc68710ad2b30a1d3b4a2ca33005af2c9460eb
DIFF: https://github.com/llvm/llvm-project/commit/04dc68710ad2b30a1d3b4a2ca33005af2c9460eb.diff
LOG: [DebugInfo][ARM] Fix incorrect debug information for RWPI accessed globals
When compiling for the RWPI relocation model the debug information is wrong:
* the debug location is described as { DW_OP_addr Var }
instead of { DW_OP_constNu Var DW_OP_bregX 0 DW_OP_plus }
* the relocation type is R_ARM_ABS32 instead of R_ARM_SBREL32
Differential Revision: https://reviews.llvm.org/D111404
Added:
llvm/test/DebugInfo/ARM/rwpi.ll
Modified:
llvm/include/llvm/Target/TargetLoweringObjectFile.h
llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
llvm/lib/Target/ARM/ARMTargetObjectFile.cpp
llvm/lib/Target/ARM/ARMTargetObjectFile.h
Removed:
################################################################################
diff --git a/llvm/include/llvm/Target/TargetLoweringObjectFile.h b/llvm/include/llvm/Target/TargetLoweringObjectFile.h
index 93bfdd20e082e..752032d3d04df 100644
--- a/llvm/include/llvm/Target/TargetLoweringObjectFile.h
+++ b/llvm/include/llvm/Target/TargetLoweringObjectFile.h
@@ -15,6 +15,7 @@
#define LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCRegister.h"
#include <cstdint>
namespace llvm {
@@ -219,6 +220,14 @@ class TargetLoweringObjectFile : public MCObjectFileInfo {
return SupportDebugThreadLocalLocation;
}
+ /// Returns the register used as static base in RWPI variants.
+ virtual const MCRegister getStaticBase() const { return MCRegister::NoRegister; }
+
+ /// Get the target specific RWPI relocation.
+ virtual const MCExpr *getIndirectSymViaRWPI(const MCSymbol *Sym) const {
+ return nullptr;
+ }
+
/// Get the target specific PC relative GOT entry relocation
virtual const MCExpr *getIndirectSymViaGOTPCRel(const GlobalValue *GV,
const MCSymbol *Sym,
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 08ec8c99d5737..b4c27dc86d8d8 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -262,14 +262,14 @@ void DwarfCompileUnit::addLocationAttribute(
if (Global) {
const MCSymbol *Sym = Asm->getSymbol(Global);
+ unsigned PointerSize = Asm->getDataLayout().getPointerSize();
+ assert((PointerSize == 4 || PointerSize == 8) &&
+ "Add support for other sizes if necessary");
if (Global->isThreadLocal()) {
if (Asm->TM.useEmulatedTLS()) {
// TODO: add debug info for emulated thread local mode.
} else {
// FIXME: Make this work with -gsplit-dwarf.
- unsigned PointerSize = Asm->getDataLayout().getPointerSize();
- assert((PointerSize == 4 || PointerSize == 8) &&
- "Add support for other sizes if necessary");
// Based on GCC's support for TLS:
if (!DD->useSplitDwarf()) {
// 1) Start with a constNu of the appropriate pointer size
@@ -292,6 +292,24 @@ void DwarfCompileUnit::addLocationAttribute(
DD->useGNUTLSOpcode() ? dwarf::DW_OP_GNU_push_tls_address
: dwarf::DW_OP_form_tls_address);
}
+ } else if (Asm->TM.getRelocationModel() == Reloc::RWPI ||
+ Asm->TM.getRelocationModel() == Reloc::ROPI_RWPI) {
+ // Constant
+ addUInt(*Loc, dwarf::DW_FORM_data1,
+ PointerSize == 4 ? dwarf::DW_OP_const4u
+ : dwarf::DW_OP_const8u);
+ // Relocation offset
+ addExpr(*Loc, PointerSize == 4 ? dwarf::DW_FORM_data4
+ : dwarf::DW_FORM_data8,
+ Asm->getObjFileLowering().getIndirectSymViaRWPI(Sym));
+ // Base register
+ Register BaseReg = Asm->getObjFileLowering().getStaticBase();
+ BaseReg = Asm->TM.getMCRegisterInfo()->getDwarfRegNum(BaseReg, false);
+ addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_breg0 + BaseReg);
+ // Offset from base register
+ addSInt(*Loc, dwarf::DW_FORM_sdata, 0);
+ // Operation
+ addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
} else {
DD->addArangeLabel(SymbolCU(this, Sym));
addOpAddress(*Loc, Sym);
diff --git a/llvm/lib/Target/ARM/ARMTargetObjectFile.cpp b/llvm/lib/Target/ARM/ARMTargetObjectFile.cpp
index b03bff92f373b..8c5438f7093be 100644
--- a/llvm/lib/Target/ARM/ARMTargetObjectFile.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetObjectFile.cpp
@@ -54,6 +54,16 @@ void ARMElfTargetObjectFile::Initialize(MCContext &Ctx,
}
}
+const MCRegister ARMElfTargetObjectFile::getStaticBase() const {
+ return ARM::R9;
+}
+
+const MCExpr *ARMElfTargetObjectFile::
+getIndirectSymViaRWPI(const MCSymbol *Sym) const {
+ return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_ARM_SBREL,
+ getContext());
+}
+
const MCExpr *ARMElfTargetObjectFile::getTTypeGlobalReference(
const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM,
MachineModuleInfo *MMI, MCStreamer &Streamer) const {
diff --git a/llvm/lib/Target/ARM/ARMTargetObjectFile.h b/llvm/lib/Target/ARM/ARMTargetObjectFile.h
index 7b15dcc61f566..8b13198fe144f 100644
--- a/llvm/lib/Target/ARM/ARMTargetObjectFile.h
+++ b/llvm/lib/Target/ARM/ARMTargetObjectFile.h
@@ -11,6 +11,7 @@
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCRegister.h"
namespace llvm {
@@ -23,6 +24,10 @@ class ARMElfTargetObjectFile : public TargetLoweringObjectFileELF {
void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
+ const MCRegister getStaticBase() const override;
+
+ const MCExpr *getIndirectSymViaRWPI(const MCSymbol *Sym) const override;
+
const MCExpr *getTTypeGlobalReference(const GlobalValue *GV,
unsigned Encoding,
const TargetMachine &TM,
diff --git a/llvm/test/DebugInfo/ARM/rwpi.ll b/llvm/test/DebugInfo/ARM/rwpi.ll
new file mode 100644
index 0000000000000..c8f73ba4803d2
--- /dev/null
+++ b/llvm/test/DebugInfo/ARM/rwpi.ll
@@ -0,0 +1,34 @@
+; RUN: llc -mtriple armv7-linux -relocation-model=rwpi -o - %s | FileCheck %s
+; RUN: llc -mtriple armv7-linux -relocation-model=ropi-rwpi -o - %s | FileCheck %s
+
+ at global = global i32 5, align 4, !dbg !0
+
+; 8 bytes of data
+; CHECK: .byte 8 @ DW_AT_location
+; DW_OP_const4u
+; CHECK-NEXT: .byte 12
+; relocation offset
+; CHECK-NEXT: .long global(sbrel)
+; DW_OP_breg9
+; CHECK-NEXT: .byte 121
+; offset from breg9
+; CHECK-NEXT: .byte 0
+; DW_OP_plus
+; CHECK-NEXT: .byte 34
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!6, !7, !8, !9, !10}
+!llvm.ident = !{!11}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "global", scope: !2, file: !3, line: 1, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 14.0.0 (https://github.com/llvm/llvm-project.git 9f5c70c7ad404f0cb52416a0574d9e48d520be5d)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "rwpi.c", directory: "/tmp")
+!4 = !{!0}
+!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!6 = !{i32 7, !"Dwarf Version", i32 4}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = !{i32 1, !"wchar_size", i32 4}
+!9 = !{i32 1, !"min_enum_size", i32 4}
+!10 = !{i32 7, !"frame-pointer", i32 2}
+!11 = !{!"clang version 14.0.0 (https://github.com/llvm/llvm-project.git 9f5c70c7ad404f0cb52416a0574d9e48d520be5d)"}
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