[ELF] - Better diagnostic for "can't create dynamic relocation" error.

[grimar]

Summary

Patch improves message to show locations for
"can't create dynamic relocation" error.

[ruiu]

ELF/Relocations.cpp

655–657

This function already took too much parameters. I wouldn't add new parameters that can be inferred from other parameters.

Don't pass C because it should be reachable from Body.

[grimar]

• Rebased + updated message.

[ruiu]

LGTM

ELF/Relocations.cpp

static RelExpr adjustExpr(const elf::ObjectFile<ELFT> &File, SymbolBody &Body,
   if (IsWrite || isStaticLinkTimeConstant<ELFT>(Expr, Type, Body, S, RelOff))
     return Expr;
 
   // This relocation would require the dynamic linker to write a value to read
   // only memory. We can hack around it if we are producing an executable and
   // the refered symbol can be preemepted to refer to the executable.
   if (Config->Shared || (Config->Pic && !isRelExpr(Expr))) {
     StringRef Name = getSymbolName(File.getStringTable(), Body);
-    error("can't create dynamic relocation " + getRelName(Type) + " against " +
-          (Name.empty() ? "readonly segment" : "symbol " + Name));
+    error(getLocation(S, RelOff) + ": can't create dynamic relocation " +
+          getRelName(Type) + " against " +
+          ((Name.empty() ? "local symbol in readonly segment"
+                         : "symbol '" + Name + "'")) +
+          " defined in " + getFilename(Body.File));
     return Expr;
   }
   if (Body.getVisibility() != STV_DEFAULT) {
     error("cannot preempt symbol " + Body.getName());
     return Expr;
   }
   if (Body.isObject()) {
     // Produce a copy relocation.
for (auto I = Rels.begin(), E = Rels.end(); I != E; ++I) {
 
     // We only report undefined symbols if they are referenced somewhere in the
     // code.
     if (!Body.isLocal() && Body.isUndefined() && !Body.symbol()->isWeak())
       reportUndefined(Body, C, RI.r_offset);
 
     RelExpr Expr = Target->getRelExpr(Type, Body);
     bool Preemptible = isPreemptible(Body, Type);
     Expr = adjustExpr(*File, Body, IsWrite, Expr, Type, Buf + RI.r_offset, C,
                       RI.r_offset);
     if (HasError)
       continue;
 
     // Skip a relocation that points to a dead piece
     // in a eh_frame section.
     while (PieceI != PieceE &&
            (PieceI->InputOff + PieceI->size() <= RI.r_offset))
       ++PieceI;
 

test/ELF/aarch64-fpic-add_abs_lo12_nc.s

 // REQUIRES: aarch64
 // RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
 // RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-// CHECK: can't create dynamic relocation R_AARCH64_ADD_ABS_LO12_NC against symbol dat
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_AARCH64_ADD_ABS_LO12_NC against symbol 'dat' defined in {{.*}}.o
 
   add x0, x0, :lo12:dat
 .data
 .globl dat
 dat:
   .word 0

test/ELF/aarch64-fpic-adr_prel_lo21.s

 // REQUIRES: aarch64
 // RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
 // RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-// CHECK: can't create dynamic relocation R_AARCH64_ADR_PREL_LO21 against symbol dat
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_AARCH64_ADR_PREL_LO21 against symbol 'dat' defined in {{.*}}.o
 
   adr x0, dat
 .data
 .globl dat
 dat:
   .word 0

test/ELF/aarch64-fpic-adr_prel_pg_hi21.s

 // REQUIRES: aarch64
 // RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
 // RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-// CHECK: can't create dynamic relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol dat
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol 'dat' defined in {{.*}}.o
 
   adrp x0, dat
 .data
 .globl dat
 dat:
   .word 0

test/ELF/aarch64-fpic-ldst32_abs_lo12_nc.s

 // REQUIRES: aarch64
 // RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
 // RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-// CHECK: can't create dynamic relocation R_AARCH64_LDST32_ABS_LO12_NC against symbol dat
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_AARCH64_LDST32_ABS_LO12_NC against symbol 'dat' defined in {{.*}}.o
 
   ldr s4, [x0, :lo12:dat]
 .data
 .globl dat
 dat:
   .word 0

test/ELF/aarch64-fpic-ldst64_abs_lo12_nc.s

 // REQUIRES: aarch64
 // RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
 // RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-// CHECK: can't create dynamic relocation R_AARCH64_LDST64_ABS_LO12_NC against symbol dat
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_AARCH64_LDST64_ABS_LO12_NC against symbol 'dat' defined in {{.*}}.o
 
   ldr x0, [x0, :lo12:dat]
 .data
 .globl dat
 dat:
   .word 0

test/ELF/aarch64-fpic-ldst8_abs_lo12_nc.s

 // REQUIRES: aarch64
 // RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
 // RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-// CHECK: can't create dynamic relocation R_AARCH64_LDST8_ABS_LO12_NC against symbol dat
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_AARCH64_LDST8_ABS_LO12_NC against symbol 'dat' defined in {{.*}}.o
 
   ldrsb x0, [x1, :lo12:dat]
 .data
 .globl dat
 dat:
   .word 0

test/ELF/arm-target1.s

.text
   patatino:
 
 // RELATIVE: Disassembly of section .text:
 // RELATIVE: $d.0:
 // RELATIVE:     1000:       04 00 00 00     .word   0x00000004
 // RELATIVE: SYMBOL TABLE:
 // RELATIVE: 00001004         .text           00000000 patatino
 
-// ABS: can't create dynamic relocation R_ARM_TARGET1 against symbol patatino
+// ABS: {{.*}}.o (.text+0x0): can't create dynamic relocation R_ARM_TARGET1 against symbol 'patatino' defined in {{.*}}.o

test/ELF/copy-in-shared.s

 // REQUIRES: x86
 // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/copy-in-shared.s -o %t1.o
 // RUN: ld.lld -shared %t1.o -o %t1.so
 // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t2.o
 // RUN: not ld.lld %t2.o %t1.so -o %t2.so -shared 2>&1 | FileCheck %s
 
 
 .quad foo
 
-// CHECK: can't create dynamic relocation R_X86_64_64 against symbol foo
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_X86_64_64 against symbol 'foo' defined in {{.*}}.so

test/ELF/copy-rel-pie-error.s

 // RUN: llvm-mc %s -o %t.o -filetype=obj -triple=x86_64-pc-linux
 // RUN: llvm-mc %p/Inputs/copy-rel-pie.s -o %t2.o -filetype=obj -triple=x86_64-pc-linux
 // RUN: ld.lld %t2.o -o %t2.so -shared
 // RUN: not ld.lld %t.o %t2.so -o %t.exe -pie 2>&1 | FileCheck %s
 
-// CHECK: can't create dynamic relocation R_X86_64_64 against symbol bar
-// CHECK: can't create dynamic relocation R_X86_64_64 against symbol foo
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_X86_64_64 against symbol 'bar' defined in {{.*}}.so
+// CHECK: {{.*}}.o (.text+0x8): can't create dynamic relocation R_X86_64_64 against symbol 'foo' defined in {{.*}}.so
 
 .global _start
 _start:
         .quad bar
         .quad foo

test/ELF/dynamic-reloc-in-ro.s

 // REQUIRES: x86
 // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
 // RUN: not ld.lld %t.o -o %t.so -shared 2>&1 | FileCheck %s
 
 foo:
 .quad foo
 
-// CHECK: can't create dynamic relocation R_X86_64_64 against readonly segment
+// CHECK: {{.*}}.o (.text+0x0): can't create dynamic relocation R_X86_64_64 against local symbol in readonly segment defined in {{.*}}.o

test/ELF/eh-frame-dyn-rel.s

 // REQUIRES: x86
 // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
 // RUN: not ld.lld %t.o %t.o -o %t -shared 2>&1 | FileCheck %s
 
         .section        bar,"axG",@progbits,foo,comdat
         .cfi_startproc
         .cfi_personality 0x8c, foo
         .cfi_endproc
 
-// CHECK: can't create dynamic relocation R_X86_64_64 against symbol foo
+// CHECK: {{.*}}.o  (.eh_frame+0x12): can't create dynamic relocation R_X86_64_64 against symbol 'foo' defined in {{.*}}.o