llvm/0001-SystemZ-Improve-error-messages-for-unsupported-reloc.patch

From efbaf8bc61f4c0e29a3eaafb11ac0ddda8bd3dff Mon Sep 17 00:00:00 2001
From: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Date: Fri, 30 Jun 2023 16:02:56 +0200
Subject: [PATCH] [SystemZ] Improve error messages for unsupported relocations

In the SystemZMCObjectWriter, we currently just abort in case
some unsupported relocation in requested.  However, as this
situation can be triggered by invalid (inline) assembler input,
we should really get a regular error message instead.
---
 .../MCTargetDesc/SystemZMCObjectWriter.cpp    | 59 +++++++++++--------
 1 file changed, 35 insertions(+), 24 deletions(-)

diff --git a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCObjectWriter.cpp b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCObjectWriter.cpp
index c23463ab9bde..0b11468afc52 100644
--- a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCObjectWriter.cpp
+++ b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCObjectWriter.cpp
@@ -9,6 +9,7 @@
 #include "MCTargetDesc/SystemZMCFixups.h"
 #include "MCTargetDesc/SystemZMCTargetDesc.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCELFObjectWriter.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCFixup.h"
@@ -40,7 +41,7 @@ SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
                             /*HasRelocationAddend_=*/ true) {}
 
 // Return the relocation type for an absolute value of MCFixupKind Kind.
-static unsigned getAbsoluteReloc(unsigned Kind) {
+static unsigned getAbsoluteReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
   switch (Kind) {
   case FK_Data_1: return ELF::R_390_8;
   case FK_Data_2: return ELF::R_390_16;
@@ -49,11 +50,12 @@ static unsigned getAbsoluteReloc(unsigned Kind) {
   case SystemZ::FK_390_12: return ELF::R_390_12;
   case SystemZ::FK_390_20: return ELF::R_390_20;
   }
-  llvm_unreachable("Unsupported absolute address");
+  Ctx.reportError(Loc, "Unsupported absolute address");
+  return 0;
 }
 
 // Return the relocation type for a PC-relative value of MCFixupKind Kind.
-static unsigned getPCRelReloc(unsigned Kind) {
+static unsigned getPCRelReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
   switch (Kind) {
   case FK_Data_2:                return ELF::R_390_PC16;
   case FK_Data_4:                return ELF::R_390_PC32;
@@ -63,62 +65,69 @@ static unsigned getPCRelReloc(unsigned Kind) {
   case SystemZ::FK_390_PC24DBL:  return ELF::R_390_PC24DBL;
   case SystemZ::FK_390_PC32DBL:  return ELF::R_390_PC32DBL;
   }
-  llvm_unreachable("Unsupported PC-relative address");
+  Ctx.reportError(Loc, "Unsupported PC-relative address");
+  return 0;
 }
 
 // Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
-static unsigned getTLSLEReloc(unsigned Kind) {
+static unsigned getTLSLEReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
   switch (Kind) {
   case FK_Data_4: return ELF::R_390_TLS_LE32;
   case FK_Data_8: return ELF::R_390_TLS_LE64;
   }
-  llvm_unreachable("Unsupported absolute address");
+  Ctx.reportError(Loc, "Unsupported thread-local address (local-exec)");
+  return 0;
 }
 
 // Return the R_390_TLS_LDO* relocation type for MCFixupKind Kind.
-static unsigned getTLSLDOReloc(unsigned Kind) {
+static unsigned getTLSLDOReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
   switch (Kind) {
   case FK_Data_4: return ELF::R_390_TLS_LDO32;
   case FK_Data_8: return ELF::R_390_TLS_LDO64;
   }
-  llvm_unreachable("Unsupported absolute address");
+  Ctx.reportError(Loc, "Unsupported thread-local address (local-dynamic)");
+  return 0;
 }
 
 // Return the R_390_TLS_LDM* relocation type for MCFixupKind Kind.
-static unsigned getTLSLDMReloc(unsigned Kind) {
+static unsigned getTLSLDMReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
   switch (Kind) {
   case FK_Data_4: return ELF::R_390_TLS_LDM32;
   case FK_Data_8: return ELF::R_390_TLS_LDM64;
   case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_LDCALL;
   }
-  llvm_unreachable("Unsupported absolute address");
+  Ctx.reportError(Loc, "Unsupported thread-local address (local-dynamic)");
+  return 0;
 }
 
 // Return the R_390_TLS_GD* relocation type for MCFixupKind Kind.
-static unsigned getTLSGDReloc(unsigned Kind) {
+static unsigned getTLSGDReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
   switch (Kind) {
   case FK_Data_4: return ELF::R_390_TLS_GD32;
   case FK_Data_8: return ELF::R_390_TLS_GD64;
   case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_GDCALL;
   }
-  llvm_unreachable("Unsupported absolute address");
+  Ctx.reportError(Loc, "Unsupported thread-local address (general-dynamic)");
+  return 0;
 }
 
 // Return the PLT relocation counterpart of MCFixupKind Kind.
-static unsigned getPLTReloc(unsigned Kind) {
+static unsigned getPLTReloc(MCContext &Ctx, SMLoc Loc, unsigned Kind) {
   switch (Kind) {
   case SystemZ::FK_390_PC12DBL: return ELF::R_390_PLT12DBL;
   case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
   case SystemZ::FK_390_PC24DBL: return ELF::R_390_PLT24DBL;
   case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
   }
-  llvm_unreachable("Unsupported absolute address");
+  Ctx.reportError(Loc, "Unsupported PC-relative PLT address");
+  return 0;
 }
 
 unsigned SystemZObjectWriter::getRelocType(MCContext &Ctx,
                                            const MCValue &Target,
                                            const MCFixup &Fixup,
                                            bool IsPCRel) const {
+  SMLoc Loc = Fixup.getLoc();
   unsigned Kind = Fixup.getKind();
   if (Kind >= FirstLiteralRelocationKind)
     return Kind - FirstLiteralRelocationKind;
@@ -126,38 +135,40 @@ unsigned SystemZObjectWriter::getRelocType(MCContext &Ctx,
   switch (Modifier) {
   case MCSymbolRefExpr::VK_None:
     if (IsPCRel)
-      return getPCRelReloc(Kind);
-    return getAbsoluteReloc(Kind);
+      return getPCRelReloc(Ctx, Loc, Kind);
+    return getAbsoluteReloc(Ctx, Loc, Kind);
 
   case MCSymbolRefExpr::VK_NTPOFF:
     assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
-    return getTLSLEReloc(Kind);
+    return getTLSLEReloc(Ctx, Loc, Kind);
 
   case MCSymbolRefExpr::VK_INDNTPOFF:
     if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
       return ELF::R_390_TLS_IEENT;
-    llvm_unreachable("Only PC-relative INDNTPOFF accesses are supported for now");
+    Ctx.reportError(Loc, "Only PC-relative INDNTPOFF accesses are supported for now");
+    return 0;
 
   case MCSymbolRefExpr::VK_DTPOFF:
     assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
-    return getTLSLDOReloc(Kind);
+    return getTLSLDOReloc(Ctx, Loc, Kind);
 
   case MCSymbolRefExpr::VK_TLSLDM:
     assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
-    return getTLSLDMReloc(Kind);
+    return getTLSLDMReloc(Ctx, Loc, Kind);
 
   case MCSymbolRefExpr::VK_TLSGD:
     assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
-    return getTLSGDReloc(Kind);
+    return getTLSGDReloc(Ctx, Loc, Kind);
 
   case MCSymbolRefExpr::VK_GOT:
     if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
       return ELF::R_390_GOTENT;
-    llvm_unreachable("Only PC-relative GOT accesses are supported for now");
+    Ctx.reportError(Loc, "Only PC-relative GOT accesses are supported for now");
+    return 0;
 
   case MCSymbolRefExpr::VK_PLT:
-    assert(IsPCRel && "@PLT shouldt be PC-relative");
-    return getPLTReloc(Kind);
+    assert(IsPCRel && "@PLT shouldn't be PC-relative");
+    return getPLTReloc(Ctx, Loc, Kind);
 
   default:
     llvm_unreachable("Modifier not supported");
-- 
2.41.0