From 48fc7daddbc64a9de761293c3a6795567cc83801 Mon Sep 17 00:00:00 2001
From: Tsukasa OI <research_trasio@irq.a4lg.com>
Date: Mon, 5 Sep 2022 08:11:54 +0000
Subject: [PATCH] RISC-V: Imply 'Zicsr' from privileged extensions with CSRs

'H', 'Smstateen', 'Sscofpmf' and 'Sstc' are four privileged extensions with
their CSR definitions and 'Smepmp' is a privileged extension with additional
CSR bits.

Volume II: Privileged Architecture of the RISC-V ISA Manual states that the
privileged architecture requires the 'Zicsr' extension.  However, current
GNU Binutils has no direct way whether the program has dependency to the
privileged architecture itself.

As a workaround, we should add implications from privileged extensions that
either add new CSRs, extend existing CSRs or depends on using CSRs.

This commit adds such implications for existing privileged extensions that
satisfy this condition.

gas/ChangeLog:

	* testsuite/gas/riscv/march-imply-h.d: New test, at least for 'H'.

bfd/ChangeLog:

	* elfxx-riscv.c (riscv_implicit_subsets): Add 'Zicsr'
	implicications for privileged extensions 'H', 'Smstateen',
	'Sscofpmf', 'Sstc' and 'Smepmp'.
---
 bfd/elfxx-riscv.c                       | 5 +++++
 gas/testsuite/gas/riscv/march-imply-h.d | 6 ++++++
 2 files changed, 11 insertions(+)
 create mode 100644 gas/testsuite/gas/riscv/march-imply-h.d

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 1bcc6c0acb4..f0c91cc97f7 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1047,6 +1047,7 @@ static struct riscv_implicit_subset riscv_implicit_subsets[] =
   {"g", "zicsr",	check_implicit_always},
   {"g", "zifencei",	check_implicit_always},
   {"m", "zmmul",	check_implicit_always},
+  {"h", "zicsr",	check_implicit_always},
   {"q", "d",		check_implicit_always},
   {"v", "d",		check_implicit_always},
   {"v", "zve64d",	check_implicit_always},
@@ -1096,6 +1097,10 @@ static struct riscv_implicit_subset riscv_implicit_subsets[] =
   {"zks", "zbkx",	check_implicit_always},
   {"zks", "zksed",	check_implicit_always},
   {"zks", "zksh",	check_implicit_always},
+  {"smepmp", "zicsr",		check_implicit_always},
+  {"smstateen", "zicsr",	check_implicit_always},
+  {"sscofpmf", "zicsr",		check_implicit_always},
+  {"sstc", "zicsr",		check_implicit_always},
   {NULL, NULL, NULL}
 };
 
diff --git a/gas/testsuite/gas/riscv/march-imply-h.d b/gas/testsuite/gas/riscv/march-imply-h.d
new file mode 100644
index 00000000000..04ad9f6c0a5
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-imply-h.d
@@ -0,0 +1,6 @@
+#as: -march=rv32ih -march-attr -misa-spec=20191213 -mpriv-spec=1.12
+#readelf: -A
+#source: empty.s
+Attribute Section: riscv
+File Attributes
+  Tag_RISCV_arch: "rv32i2p1_h1p0_zicsr2p0"