The constraint "S" can only be used with a symbol that binds locally, so
the following does not work for -fpie/-fpic (GOT access is used).
```
namespace ns { extern int var, a[4]; }
void foo() {
asm(".pushsection .xxx,\"aw\"; .dc.a %0; .popsection" :: "S"(&ns::var));
asm(".reloc ., BFD_RELOC_NONE, %0" :: "S"(&ns::a[3]));
}
```
This is overly restrictive, as many references like an absolute
relocation in a writable section or a non-SHF_ALLOC section should be
totally fine. Allow symbols that do not bind locally, similar to
aarch64 "S" and x86-64 "Ws" (commit d7250100381b817114447d91fff4748526d4fb21).
gcc/ChangeLog:
* config/riscv/constraints.md: Relax the condition for "S".
* doc/md.texi: Update.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/asm-raw-symbol.c: New test.
---
gcc/config/riscv/constraints.md | 4 ++--
gcc/doc/md.texi | 2 +-
gcc/testsuite/gcc.target/riscv/asm-raw-symbol.c | 17 +++++++++++++++++
3 files changed, 20 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/asm-raw-symbol.c
diff --git a/gcc/config/riscv/constraints.md b/gcc/config/riscv/constraints.md
index 41acaea04eb..bb012668fcb 100644
--- a/gcc/config/riscv/constraints.md
+++ b/gcc/config/riscv/constraints.md
@@ -121,8 +121,8 @@ (define_memory_constraint "A"
(match_test "GET_CODE(XEXP(op,0)) == REG")))
(define_constraint "S"
- "A constraint that matches an absolute symbolic address."
- (match_operand 0 "absolute_symbolic_operand"))
+ "A symbolic reference or label reference."
+ (match_code "const,symbol_ref,label_ref"))
(define_constraint "U"
"@internal
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index b0c61925120..c75e5bf259d 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -1947,7 +1947,7 @@ Integer constant that is valid as an immediate operand in
a 64-bit @code{MOV}
pseudo instruction
@item S
-An absolute symbolic address or a label reference
+A symbolic reference or label reference.
@item Y
Floating point constant zero
diff --git a/gcc/testsuite/gcc.target/riscv/asm-raw-symbol.c
b/gcc/testsuite/gcc.target/riscv/asm-raw-symbol.c
new file mode 100644
index 00000000000..eadf6d23fe1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/asm-raw-symbol.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-fpic" } */
+
+extern int var;
+
+void
+func (void)
+{
+label:
+ __asm__ ("@ %0" : : "S" (func));
+ __asm__ ("@ %0" : : "S" (&var + 1));
+ __asm__ ("@ %0" : : "S" (&&label));
+}
+
+/* { dg-final { scan-assembler "@ func" } } */
+/* { dg-final { scan-assembler "@ var\\+4" } } */
+/* { dg-final { scan-assembler "@ .L" } } */
--
2.43.0.429.g432eaa2c6b-goog
