[gcc r15-5194] RISC-V: Implement Priority syntax parser for Function Multi-Versioning

[Kito Cheng via Gcc-cvs]

https://gcc.gnu.org/g:6b572d4eecc99c4a014ce1eab5e79976e30f4d9f

commit r15-5194-g6b572d4eecc99c4a014ce1eab5e79976e30f4d9f
Author: Yangyu Chen <c...@cyyself.name>
Date:   Tue Nov 5 11:22:00 2024 +0800

    RISC-V: Implement Priority syntax parser for Function Multi-Versioning
    
    This patch adds the priority syntax parser to support the Function
    Multi-Versioning (FMV) feature in RISC-V. This feature allows users to
    specify the priority of the function version in the attribute syntax.
    
    Chnages based on RISC-V C-API PR:
    https://github.com/riscv-non-isa/riscv-c-api-doc/pull/85
    
    Signed-off-by: Yangyu Chen <c...@cyyself.name>
    
    gcc/ChangeLog:
    
            * config/riscv/riscv-target-attr.cc
            (riscv_target_attr_parser::handle_priority): New function.
            (riscv_target_attr_parser::update_settings): Update priority
            attribute.
            * config/riscv/riscv.opt: Add TargetVariable riscv_fmv_priority.

Diff:
---
 gcc/config/riscv/riscv-target-attr.cc | 24 ++++++++++++++++++++++++
 gcc/config/riscv/riscv.opt            |  3 +++
 2 files changed, 27 insertions(+)

diff --git a/gcc/config/riscv/riscv-target-attr.cc 
b/gcc/config/riscv/riscv-target-attr.cc
index 8ce9607b3c9b..293d53212156 100644
--- a/gcc/config/riscv/riscv-target-attr.cc
+++ b/gcc/config/riscv/riscv-target-attr.cc
@@ -39,16 +39,19 @@ public:
     : m_found_arch_p (false)
     , m_found_tune_p (false)
     , m_found_cpu_p (false)
+    , m_found_priority_p (false)
     , m_subset_list (nullptr)
     , m_loc (loc)
     , m_cpu_info (nullptr)
     , m_tune (nullptr)
+    , m_priority (0)
   {
   }
 
   bool handle_arch (const char *);
   bool handle_cpu (const char *);
   bool handle_tune (const char *);
+  bool handle_priority (const char *);
 
   void update_settings (struct gcc_options *opts) const;
 private:
@@ -58,10 +61,12 @@ private:
   bool m_found_arch_p;
   bool m_found_tune_p;
   bool m_found_cpu_p;
+  bool m_found_priority_p;
   riscv_subset_list *m_subset_list;
   location_t m_loc;
   const  riscv_cpu_info *m_cpu_info;
   const char *m_tune;
+  int m_priority;
 };
 }
 
@@ -210,6 +215,22 @@ riscv_target_attr_parser::handle_tune (const char *str)
   return true;
 }
 
+bool
+riscv_target_attr_parser::handle_priority (const char *str)
+{
+  if (m_found_priority_p)
+    error_at (m_loc, "%<target()%> attribute: priority appears more than 
once");
+  m_found_priority_p = true;
+
+  if (sscanf (str, "%d", &m_priority) != 1)
+    {
+      error_at (m_loc, "%<target()%> attribute: invalid priority %qs", str);
+      return false;
+    }
+
+  return true;
+}
+
 void
 riscv_target_attr_parser::update_settings (struct gcc_options *opts) const
 {
@@ -236,6 +257,9 @@ riscv_target_attr_parser::update_settings (struct 
gcc_options *opts) const
       if (m_cpu_info)
        opts->x_riscv_tune_string = m_cpu_info->tune;
     }
+
+  if (m_priority)
+    opts->x_riscv_fmv_priority = m_priority;
 }
 
 /* Parse ARG_STR which contains the definition of one target attribute.
diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt
index 5bc5d3002934..ab9d6e827231 100644
--- a/gcc/config/riscv/riscv.opt
+++ b/gcc/config/riscv/riscv.opt
@@ -523,6 +523,9 @@ Mask(XSFVCP) Var(riscv_sifive_subext)
 
 Mask(XSFCEASE) Var(riscv_sifive_subext)
 
+TargetVariable
+int riscv_fmv_priority = 0
+
 Enum
 Name(isa_spec_class) Type(enum riscv_isa_spec_class)
 Supported ISA specs (for use with the -misa-spec= option):