From 09c46b149ec8bd1e419778c657a4d4825e72a0bf Mon Sep 17 00:00:00 2001
From: David Semakula <davidsemakula@users.noreply.github.com>
Date: Wed, 26 Feb 2025 08:49:59 +0300
Subject: [PATCH] Retrieve PolkaVM target spec from linker (#1939)
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* Retrieve PolkaVM target spec from linker

* Update changelog

---------

Co-authored-by: Michael Müller <mich@elmueller.net>
---
 CHANGELOG.md                                  |  3 ++-
 .../riscv64emac-unknown-none-polkavm.json     | 26 -------------------
 crates/build/src/args.rs                      | 20 +++++++++-----
 3 files changed, 15 insertions(+), 34 deletions(-)
 delete mode 100644 crates/build/riscv64emac-unknown-none-polkavm.json

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fd9ab0100..9bbd052fd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,11 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [Unreleased]
 
 ### Added
-- Add option to generate Solidity compatible metadata (via `cargo contract build ---metadata <ink|solidity>`) - [1930](https://github.com/use-ink/cargo-contract/pull/1930)
+- Add option to generate Solidity compatible metadata (via `cargo contract build ---metadata <ink|solidity>`) - [#1930](https://github.com/use-ink/cargo-contract/pull/1930)
 - Deny overflowing (and lossy) integer type cast operations - [#1895](https://github.com/use-ink/cargo-contract/pull/1895)
 
 ### Changed
 - Target `pallet-revive` instead of `pallet-contracts` - [#1851](https://github.com/use-ink/cargo-contract/pull/1851)
+- Retrieve PolkaVM target spec from linker - [#1939](https://github.com/use-ink/cargo-contract/pull/1939)
 
 ## [5.0.1]
 
diff --git a/crates/build/riscv64emac-unknown-none-polkavm.json b/crates/build/riscv64emac-unknown-none-polkavm.json
deleted file mode 100644
index a3473ee01..000000000
--- a/crates/build/riscv64emac-unknown-none-polkavm.json
+++ /dev/null
@@ -1,26 +0,0 @@
-{
-    "arch": "riscv64",
-    "cpu": "generic-rv64",
-    "crt-objects-fallback": "false",
-    "data-layout": "e-m:e-p:64:64-i64:64-i128:128-n32:64-S64",
-    "eh-frame-header": false,
-    "emit-debug-gdb-scripts": false,
-    "features": "+e,+m,+a,+c,+auipc-addi-fusion,+ld-add-fusion,+lui-addi-fusion,+xtheadcondmov",
-    "linker": "rust-lld",
-    "linker-flavor": "ld.lld",
-    "llvm-abiname": "lp64e",
-    "llvm-target": "riscv64",
-    "max-atomic-width": 64,
-    "panic-strategy": "abort",
-    "relocation-model": "pie",
-    "target-pointer-width": "64",
-    "singlethread": true,
-    "pre-link-args": {
-        "ld": [
-            "--emit-relocs",
-            "--unique",
-            "--relocatable"
-        ]
-    },
-    "env": "polkavm"
-}
diff --git a/crates/build/src/args.rs b/crates/build/src/args.rs
index 324620279..97d30efb0 100644
--- a/crates/build/src/args.rs
+++ b/crates/build/src/args.rs
@@ -14,9 +14,6 @@
 // You should have received a copy of the GNU General Public License
 // along with cargo-contract.  If not, see <http://www.gnu.org/licenses/>.
 
-use crate::CrateMetadata;
-use anyhow::Result;
-use clap::Args;
 use std::{
     convert::TryFrom,
     fmt,
@@ -26,6 +23,15 @@ use std::{
     path::Path,
 };
 
+use anyhow::Result;
+use clap::Args;
+use polkavm_linker::TARGET_JSON_64_BIT as POLKAVM_TARGET_JSON_64_BIT;
+
+use crate::CrateMetadata;
+
+/// Name of the rustc/LLVM custom target spec for PolkaVM.
+const POLKAVM_TARGET_NAME: &str = "riscv64emac-unknown-none-polkavm";
+
 #[derive(Default, Clone, Copy, Debug, Args)]
 pub struct VerbosityFlags {
     /// No output printed to stdout
@@ -145,21 +151,21 @@ impl Target {
         // target configuration here. The path to the file is passed for the
         // `rustc --target` argument. We write this file to the `target/` folder.
         let target_dir = crate_metadata.target_directory.to_string_lossy();
-        let path = format!("{}/riscv64emac-unknown-none-polkavm.json", target_dir);
+        let path = format!("{}/{POLKAVM_TARGET_NAME}.json", target_dir);
         if !Path::exists(Path::new(&path)) {
             fs::create_dir_all(&crate_metadata.target_directory).unwrap_or_else(|e| {
                 panic!("unable to create target dir {:?}: {:?}", target_dir, e)
             });
             let mut file = File::create(&path).unwrap();
-            let config = include_str!("../riscv64emac-unknown-none-polkavm.json");
-            file.write_all(config.as_bytes()).unwrap();
+            file.write_all(POLKAVM_TARGET_JSON_64_BIT.as_bytes())
+                .unwrap();
         }
         path
     }
 
     /// The name used for the target folder inside the `target/` folder.
     pub fn llvm_target_alias() -> &'static str {
-        "riscv64emac-unknown-none-polkavm"
+        POLKAVM_TARGET_NAME
     }
 
     /// Target specific flags to be set to `CARGO_ENCODED_RUSTFLAGS` while building.