[LLD][RISCV] Fix incorrect call relaxation when mixing +c and -c objects

lld/ELF/Arch/RISCV.cpp

@@ -591,7 +591,7 @@ static void initSymbolAnchors() {
 // Relax R_RISCV_CALL/R_RISCV_CALL_PLT auipc+jalr to c.j, c.jal, or jal.
 static void relaxCall(const InputSection &sec, size_t i, uint64_t loc,
                       Relocation &r, uint32_t &remove) {
-  const bool rvc = config->eflags & EF_RISCV_RVC;
+  const bool rvc = getEFlags(sec.file) & EF_RISCV_RVC;
   const Symbol &sym = *r.sym;
   const uint64_t insnPair = read64le(sec.content().data() + r.offset);
   const uint32_t rd = extractBits(insnPair, 32 + 11, 32 + 7);

lld/test/ELF/riscv-relax-call-mixed-rvc.s

@@ -0,0 +1,32 @@
+# REQUIRES: riscv
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c,+relax a.s -o a.o
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=-c,+relax b.s -o b.o
+
+# RUN: ld.lld a.o b.o --shared -o a -Ttext=0x10000
+# RUN: llvm-objdump -d --no-show-raw-insn -M no-aliases a | FileCheck %s
+
+## This needs to be a *uncompressed* jal instruction since it came from the
+## source file which does not enable C
+# CHECK-LABEL: <foo>:
+# CHECK-NEXT:    10000: jal zero, {{.*}} <foo>
+# CHECK-NEXT:    10004: sub zero, zero, zero
+
+# w/ C
+#--- a.s
+	.text
+	.attribute	4, 16
+	.attribute	5, "rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0_zifencei2p0"
+
+# w/o C
+#--- b.s
+	.text
+	.attribute	4, 16
+	.attribute	5, "rv64i2p1_m2p0_a2p1_f2p2_d2p2_zicsr2p0_zifencei2p0"
+	.p2align	5
+	.type	foo,@function
+foo:
+    tail    foo
+    # Pick a non-canonical nop to ensure test output can't be confused
+    # with riscv_align padding
+    sub zero, zero, zero