[lld/ELF] Hint if R_X86_64_PC32 overflows and references a SHF_X86_64_LARGE section (#73045)
Makes it clearer what the issue is when hand-written assembly doesn't
follow medium code model assumptions in a medium code model build.
Alternative to #71248 by only hinting on an overflow.
GitOrigin-RevId: 1d4c0092a82aa351c5a6e9e501cc5edbc6c0477f
diff --git a/ELF/Relocations.cpp b/ELF/Relocations.cpp
index af974d0..59b0220 100644
--- a/ELF/Relocations.cpp
+++ b/ELF/Relocations.cpp
@@ -105,6 +105,13 @@
hint = "; references '" + lld::toString(*rel.sym) + '\'';
else if (auto *d = dyn_cast<Defined>(rel.sym))
hint = ("; references section '" + d->section->name + "'").str();
+
+ if (config->emachine == EM_X86_64 && rel.type == R_X86_64_PC32 &&
+ rel.sym->getOutputSection() &&
+ (rel.sym->getOutputSection()->flags & SHF_X86_64_LARGE)) {
+ hint += "; R_X86_64_PC32 should not reference a section marked "
+ "SHF_X86_64_LARGE";
+ }
}
if (!errPlace.srcLoc.empty())
hint += "\n>>> referenced by " + errPlace.srcLoc;
diff --git a/test/ELF/x86-64-pc32-overflow-large.s b/test/ELF/x86-64-pc32-overflow-large.s
new file mode 100644
index 0000000..fb8f3e4
--- /dev/null
+++ b/test/ELF/x86-64-pc32-overflow-large.s
@@ -0,0 +1,25 @@
+# REQUIRES: x86
+# RUN: split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/a.s -o %t/a.o
+# RUN: not ld.lld %t/a.o -T %t/lds -o /dev/null 2>&1 | FileCheck %s
+
+# CHECK: error: {{.*}}a.o:(.text+{{.*}}): relocation R_X86_64_PC32 out of range: {{.*}}; R_X86_64_PC32 should not reference a section marked SHF_X86_64_LARGE
+
+#--- a.s
+.text
+.globl _start
+.type _start, @function
+_start:
+ movq hello(%rip), %rax
+
+.section ldata,"awl",@progbits
+.type hello, @object
+.globl hello
+hello:
+.long 1
+
+#--- lds
+SECTIONS {
+ .text 0x100000 : { *(.text) }
+ ldata 0x80200000 : { *(ldata) }
+}
