From 6b47079884e9f816b1c4b9790718de6db3fe1bc2 Mon Sep 17 00:00:00 2001
From: Carlo Kok <ck@remobjects.com>
Date: Sat, 6 Jun 2020 16:08:21 +0200
Subject: [PATCH 1/6] Cranelift: Module data apis should allow specifying the
 object file section #1640

---
 cranelift/module/src/data_context.rs |  8 ++++++
 cranelift/object/src/backend.rs      | 39 +++++++++++++++++-----------
 2 files changed, 32 insertions(+), 15 deletions(-)

diff --git a/cranelift/module/src/data_context.rs b/cranelift/module/src/data_context.rs
index 94dbeb0b98..a20d734cd2 100644
--- a/cranelift/module/src/data_context.rs
+++ b/cranelift/module/src/data_context.rs
@@ -46,6 +46,8 @@ pub struct DataDescription {
     pub function_relocs: Vec<(CodeOffset, ir::FuncRef)>,
     /// Data addresses to write at specified offsets.
     pub data_relocs: Vec<(CodeOffset, ir::GlobalValue, Addend)>,
+    /// Object file section
+    pub section: Option<(std::string::String, std::string::String)>
 }
 
 /// This is to data objects what cranelift_codegen::Context is to functions.
@@ -63,6 +65,7 @@ impl DataContext {
                 data_decls: PrimaryMap::new(),
                 function_relocs: vec![],
                 data_relocs: vec![],
+                section: None
             },
         }
     }
@@ -90,6 +93,11 @@ impl DataContext {
         self.description.init = Init::Bytes { contents };
     }
 
+    /// Override the segment/section for data, only supported on Object backend
+    pub fn set_section(&mut self, seg: &str, sec: &str) {
+        self.description.section = Some((std::string::String::from(seg), std::string::String::from(sec)))
+    }
+
     /// Declare an external function import.
     ///
     /// Users of the `Module` API generally should call
diff --git a/cranelift/object/src/backend.rs b/cranelift/object/src/backend.rs
index 664dd34ab2..665e8021e1 100644
--- a/cranelift/object/src/backend.rs
+++ b/cranelift/object/src/backend.rs
@@ -234,6 +234,7 @@ impl Backend for ObjectBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
+            section: ref datasection
         } = data_ctx.description();
 
         let reloc_size = match self.isa.triple().pointer_width().unwrap() {
@@ -264,22 +265,30 @@ impl Backend for ObjectBackend {
         }
 
         let symbol = self.data_objects[data_id].unwrap();
-        let section_kind = if let Init::Zeros { .. } = *init {
-            if tls {
-                StandardSection::UninitializedTls
+        let section = 
+            if datasection.is_none() {
+                let section_kind = if let Init::Zeros { .. } = *init {
+                    if tls {
+                        StandardSection::UninitializedTls
+                    } else {
+                        StandardSection::UninitializedData
+                    }
+                } else if tls {
+                    StandardSection::Tls
+                } else if writable {
+                    StandardSection::Data
+                } else if relocs.is_empty() {
+                    StandardSection::ReadOnlyData
+                } else {
+                    StandardSection::ReadOnlyDataWithRel
+                };
+                self.object.section_id(section_kind)
             } else {
-                StandardSection::UninitializedData
-            }
-        } else if tls {
-            StandardSection::Tls
-        } else if writable {
-            StandardSection::Data
-        } else if relocs.is_empty() {
-            StandardSection::ReadOnlyData
-        } else {
-            StandardSection::ReadOnlyDataWithRel
-        };
-        let section = self.object.section_id(section_kind);
+                let (seg, sec) = &datasection.as_ref().unwrap();
+                self.object.add_section(seg.clone().into_bytes(), sec.clone().into_bytes(), 
+                    if writable { SectionKind::Data } else { SectionKind::ReadOnlyData }
+                )
+            };
 
         let align = u64::from(align.unwrap_or(1));
         let offset = match *init {

From 4ff01aa8989b5ff10766786b03b020b3e0e71799 Mon Sep 17 00:00:00 2001
From: Carlo Kok <ck@remobjects.com>
Date: Mon, 8 Jun 2020 07:22:36 +0200
Subject: [PATCH 2/6] Extra assertions and fix for Faerie.

---
 cranelift/faerie/src/backend.rs | 3 +++
 cranelift/object/src/backend.rs | 1 +
 2 files changed, 4 insertions(+)

diff --git a/cranelift/faerie/src/backend.rs b/cranelift/faerie/src/backend.rs
index 84352b2696..29ae59907f 100644
--- a/cranelift/faerie/src/backend.rs
+++ b/cranelift/faerie/src/backend.rs
@@ -211,8 +211,11 @@ impl Backend for FaerieBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
+            section: ref datasection
         } = data_ctx.description();
 
+        assert!(datasection.is_none(), "Custom sections not supported");
+
         for &(offset, id) in function_relocs {
             let to = &namespace.get_function_decl(&function_decls[id]).name;
             self.artifact
diff --git a/cranelift/object/src/backend.rs b/cranelift/object/src/backend.rs
index 665e8021e1..7342839fd5 100644
--- a/cranelift/object/src/backend.rs
+++ b/cranelift/object/src/backend.rs
@@ -284,6 +284,7 @@ impl Backend for ObjectBackend {
                 };
                 self.object.section_id(section_kind)
             } else {
+                assert!(!tls, "Tls data cannot be in named section");
                 let (seg, sec) = &datasection.as_ref().unwrap();
                 self.object.add_section(seg.clone().into_bytes(), sec.clone().into_bytes(), 
                     if writable { SectionKind::Data } else { SectionKind::ReadOnlyData }

From 04492983d2c6487d7ff5cae95ff1624f3b485c96 Mon Sep 17 00:00:00 2001
From: Carlo Kok <ck@remobjects.com>
Date: Mon, 8 Jun 2020 19:19:20 +0200
Subject: [PATCH 3/6] Extra assertions and fix for SimpleJit.

---
 cranelift/simplejit/src/backend.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cranelift/simplejit/src/backend.rs b/cranelift/simplejit/src/backend.rs
index fc22d62f92..f4c6af2da1 100644
--- a/cranelift/simplejit/src/backend.rs
+++ b/cranelift/simplejit/src/backend.rs
@@ -361,8 +361,11 @@ impl<'simple_jit_backend> Backend for SimpleJITBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
+            section: ref datasection,
         } = data.description();
 
+        assert!(datasection.is_none(), "Custom sections not supported");
+
         let size = init.size();
         let storage = if writable {
             self.memory

From 38531b8f426a5eb9c0b96dd2e83fa4e2ca917db5 Mon Sep 17 00:00:00 2001
From: Carlo Kok <ck@remobjects.com>
Date: Mon, 8 Jun 2020 19:56:21 +0200
Subject: [PATCH 4/6] Rust fmt fixes

---
 cranelift/faerie/src/backend.rs      |  2 +-
 cranelift/module/src/data_context.rs |  9 +++--
 cranelift/object/src/backend.rs      | 51 +++++++++++++++-------------
 3 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/cranelift/faerie/src/backend.rs b/cranelift/faerie/src/backend.rs
index 29ae59907f..192cf455f2 100644
--- a/cranelift/faerie/src/backend.rs
+++ b/cranelift/faerie/src/backend.rs
@@ -211,7 +211,7 @@ impl Backend for FaerieBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
-            section: ref datasection
+            section: ref datasection,
         } = data_ctx.description();
 
         assert!(datasection.is_none(), "Custom sections not supported");
diff --git a/cranelift/module/src/data_context.rs b/cranelift/module/src/data_context.rs
index a20d734cd2..0b732b41f7 100644
--- a/cranelift/module/src/data_context.rs
+++ b/cranelift/module/src/data_context.rs
@@ -47,7 +47,7 @@ pub struct DataDescription {
     /// Data addresses to write at specified offsets.
     pub data_relocs: Vec<(CodeOffset, ir::GlobalValue, Addend)>,
     /// Object file section
-    pub section: Option<(std::string::String, std::string::String)>
+    pub section: Option<(std::string::String, std::string::String)>,
 }
 
 /// This is to data objects what cranelift_codegen::Context is to functions.
@@ -65,7 +65,7 @@ impl DataContext {
                 data_decls: PrimaryMap::new(),
                 function_relocs: vec![],
                 data_relocs: vec![],
-                section: None
+                section: None,
             },
         }
     }
@@ -95,7 +95,10 @@ impl DataContext {
 
     /// Override the segment/section for data, only supported on Object backend
     pub fn set_section(&mut self, seg: &str, sec: &str) {
-        self.description.section = Some((std::string::String::from(seg), std::string::String::from(sec)))
+        self.description.section = Some((
+            std::string::String::from(seg),
+            std::string::String::from(sec),
+        ))
     }
 
     /// Declare an external function import.
diff --git a/cranelift/object/src/backend.rs b/cranelift/object/src/backend.rs
index 7342839fd5..1b88023028 100644
--- a/cranelift/object/src/backend.rs
+++ b/cranelift/object/src/backend.rs
@@ -234,7 +234,7 @@ impl Backend for ObjectBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
-            section: ref datasection
+            section: ref datasection,
         } = data_ctx.description();
 
         let reloc_size = match self.isa.triple().pointer_width().unwrap() {
@@ -265,31 +265,36 @@ impl Backend for ObjectBackend {
         }
 
         let symbol = self.data_objects[data_id].unwrap();
-        let section = 
-            if datasection.is_none() {
-                let section_kind = if let Init::Zeros { .. } = *init {
-                    if tls {
-                        StandardSection::UninitializedTls
-                    } else {
-                        StandardSection::UninitializedData
-                    }
-                } else if tls {
-                    StandardSection::Tls
-                } else if writable {
-                    StandardSection::Data
-                } else if relocs.is_empty() {
-                    StandardSection::ReadOnlyData
+        let section = if datasection.is_none() {
+            let section_kind = if let Init::Zeros { .. } = *init {
+                if tls {
+                    StandardSection::UninitializedTls
                 } else {
-                    StandardSection::ReadOnlyDataWithRel
-                };
-                self.object.section_id(section_kind)
+                    StandardSection::UninitializedData
+                }
+            } else if tls {
+                StandardSection::Tls
+            } else if writable {
+                StandardSection::Data
+            } else if relocs.is_empty() {
+                StandardSection::ReadOnlyData
             } else {
-                assert!(!tls, "Tls data cannot be in named section");
-                let (seg, sec) = &datasection.as_ref().unwrap();
-                self.object.add_section(seg.clone().into_bytes(), sec.clone().into_bytes(), 
-                    if writable { SectionKind::Data } else { SectionKind::ReadOnlyData }
-                )
+                StandardSection::ReadOnlyDataWithRel
             };
+            self.object.section_id(section_kind)
+        } else {
+            assert!(!tls, "Tls data cannot be in named section");
+            let (seg, sec) = &datasection.as_ref().unwrap();
+            self.object.add_section(
+                seg.clone().into_bytes(),
+                sec.clone().into_bytes(),
+                if writable {
+                    SectionKind::Data
+                } else {
+                    SectionKind::ReadOnlyData
+                },
+            )
+        };
 
         let align = u64::from(align.unwrap_or(1));
         let offset = match *init {

From 0b613caad159dd38d85dc6f1bacb719766c76610 Mon Sep 17 00:00:00 2001
From: Carlo Kok <ck@remobjects.com>
Date: Mon, 15 Jun 2020 20:46:04 +0200
Subject: [PATCH 5/6] Address concerns in pullrequests.

---
 Cargo.lock                           |  1 +
 cranelift/faerie/src/backend.rs      |  6 ++++--
 cranelift/module/src/data_context.rs | 14 ++++++++------
 cranelift/object/Cargo.toml          |  1 +
 cranelift/object/src/backend.rs      | 10 ++++++----
 cranelift/simplejit/src/backend.rs   |  4 +---
 6 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 8d73830f4f..0e769ed75b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -489,6 +489,7 @@ dependencies = [
 name = "cranelift-object"
 version = "0.64.0"
 dependencies = [
+ "anyhow",
  "cranelift-codegen",
  "cranelift-module",
  "object",
diff --git a/cranelift/faerie/src/backend.rs b/cranelift/faerie/src/backend.rs
index 192cf455f2..be2ad792cc 100644
--- a/cranelift/faerie/src/backend.rs
+++ b/cranelift/faerie/src/backend.rs
@@ -211,10 +211,12 @@ impl Backend for FaerieBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
-            section: ref datasection,
+            ref custom_segment_section,
         } = data_ctx.description();
 
-        assert!(datasection.is_none(), "Custom sections not supported");
+        if let Some((segment, section)) = custom_segment_section {
+            return Err(cranelift_module::ModuleError::Backend(anyhow::anyhow!("Custom section not supported by cranelift-faerie: `{}:{}`", segment, section)));
+        }
 
         for &(offset, id) in function_relocs {
             let to = &namespace.get_function_decl(&function_decls[id]).name;
diff --git a/cranelift/module/src/data_context.rs b/cranelift/module/src/data_context.rs
index 0b732b41f7..56e8b36024 100644
--- a/cranelift/module/src/data_context.rs
+++ b/cranelift/module/src/data_context.rs
@@ -3,7 +3,9 @@
 use cranelift_codegen::binemit::{Addend, CodeOffset};
 use cranelift_codegen::entity::PrimaryMap;
 use cranelift_codegen::ir;
+use std::borrow::ToOwned;
 use std::boxed::Box;
+use std::string::String;
 use std::vec::Vec;
 
 /// This specifies how data is to be initialized.
@@ -47,7 +49,7 @@ pub struct DataDescription {
     /// Data addresses to write at specified offsets.
     pub data_relocs: Vec<(CodeOffset, ir::GlobalValue, Addend)>,
     /// Object file section
-    pub section: Option<(std::string::String, std::string::String)>,
+    pub custom_segment_section: Option<(String, String)>,
 }
 
 /// This is to data objects what cranelift_codegen::Context is to functions.
@@ -65,7 +67,7 @@ impl DataContext {
                 data_decls: PrimaryMap::new(),
                 function_relocs: vec![],
                 data_relocs: vec![],
-                section: None,
+                custom_segment_section: None,
             },
         }
     }
@@ -94,10 +96,10 @@ impl DataContext {
     }
 
     /// Override the segment/section for data, only supported on Object backend
-    pub fn set_section(&mut self, seg: &str, sec: &str) {
-        self.description.section = Some((
-            std::string::String::from(seg),
-            std::string::String::from(sec),
+    pub fn set_segment_section(&mut self, seg: &str, sec: &str) {
+        self.description.custom_segment_section = Some((
+            seg.to_owned(),
+            sec.to_owned(),
         ))
     }
 
diff --git a/cranelift/object/Cargo.toml b/cranelift/object/Cargo.toml
index 8c4c44fc74..18429a5158 100644
--- a/cranelift/object/Cargo.toml
+++ b/cranelift/object/Cargo.toml
@@ -14,6 +14,7 @@ cranelift-module = { path = "../module", version = "0.64.0" }
 cranelift-codegen = { path = "../codegen", version = "0.64.0", default-features = false, features = ["std"] }
 object = { version = "0.18", default-features = false, features = ["write"] }
 target-lexicon = "0.10"
+anyhow = "1.0"
 
 [badges]
 maintenance = { status = "experimental" }
diff --git a/cranelift/object/src/backend.rs b/cranelift/object/src/backend.rs
index 1b88023028..5d0c0d0060 100644
--- a/cranelift/object/src/backend.rs
+++ b/cranelift/object/src/backend.rs
@@ -234,7 +234,7 @@ impl Backend for ObjectBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
-            section: ref datasection,
+            ref custom_segment_section,
         } = data_ctx.description();
 
         let reloc_size = match self.isa.triple().pointer_width().unwrap() {
@@ -265,7 +265,7 @@ impl Backend for ObjectBackend {
         }
 
         let symbol = self.data_objects[data_id].unwrap();
-        let section = if datasection.is_none() {
+        let section = if custom_segment_section.is_none() {
             let section_kind = if let Init::Zeros { .. } = *init {
                 if tls {
                     StandardSection::UninitializedTls
@@ -283,8 +283,10 @@ impl Backend for ObjectBackend {
             };
             self.object.section_id(section_kind)
         } else {
-            assert!(!tls, "Tls data cannot be in named section");
-            let (seg, sec) = &datasection.as_ref().unwrap();
+            if tls {
+                return Err(cranelift_module::ModuleError::Backend(anyhow::anyhow!("Custom section not supported for TLS")));
+            }
+            let (seg, sec) = &custom_segment_section.as_ref().unwrap();
             self.object.add_section(
                 seg.clone().into_bytes(),
                 sec.clone().into_bytes(),
diff --git a/cranelift/simplejit/src/backend.rs b/cranelift/simplejit/src/backend.rs
index f4c6af2da1..d8928f1529 100644
--- a/cranelift/simplejit/src/backend.rs
+++ b/cranelift/simplejit/src/backend.rs
@@ -361,11 +361,9 @@ impl<'simple_jit_backend> Backend for SimpleJITBackend {
             ref data_decls,
             ref function_relocs,
             ref data_relocs,
-            section: ref datasection,
+            custom_segment_section: _,
         } = data.description();
 
-        assert!(datasection.is_none(), "Custom sections not supported");
-
         let size = init.size();
         let storage = if writable {
             self.memory

From b2549d1fde8a708701b2600943ff483e81ea187c Mon Sep 17 00:00:00 2001
From: Carlo Kok <ck@remobjects.com>
Date: Wed, 17 Jun 2020 06:46:58 +0200
Subject: [PATCH 6/6] Rust fmt fixes

---
 cranelift/faerie/src/backend.rs      | 6 +++++-
 cranelift/module/src/data_context.rs | 5 +----
 cranelift/object/src/backend.rs      | 4 +++-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/cranelift/faerie/src/backend.rs b/cranelift/faerie/src/backend.rs
index be2ad792cc..8fae42a0b4 100644
--- a/cranelift/faerie/src/backend.rs
+++ b/cranelift/faerie/src/backend.rs
@@ -215,7 +215,11 @@ impl Backend for FaerieBackend {
         } = data_ctx.description();
 
         if let Some((segment, section)) = custom_segment_section {
-            return Err(cranelift_module::ModuleError::Backend(anyhow::anyhow!("Custom section not supported by cranelift-faerie: `{}:{}`", segment, section)));
+            return Err(cranelift_module::ModuleError::Backend(anyhow::anyhow!(
+                "Custom section not supported by cranelift-faerie: `{}:{}`",
+                segment,
+                section
+            )));
         }
 
         for &(offset, id) in function_relocs {
diff --git a/cranelift/module/src/data_context.rs b/cranelift/module/src/data_context.rs
index 56e8b36024..bca8471a77 100644
--- a/cranelift/module/src/data_context.rs
+++ b/cranelift/module/src/data_context.rs
@@ -97,10 +97,7 @@ impl DataContext {
 
     /// Override the segment/section for data, only supported on Object backend
     pub fn set_segment_section(&mut self, seg: &str, sec: &str) {
-        self.description.custom_segment_section = Some((
-            seg.to_owned(),
-            sec.to_owned(),
-        ))
+        self.description.custom_segment_section = Some((seg.to_owned(), sec.to_owned()))
     }
 
     /// Declare an external function import.
diff --git a/cranelift/object/src/backend.rs b/cranelift/object/src/backend.rs
index 5d0c0d0060..4ec6522061 100644
--- a/cranelift/object/src/backend.rs
+++ b/cranelift/object/src/backend.rs
@@ -284,7 +284,9 @@ impl Backend for ObjectBackend {
             self.object.section_id(section_kind)
         } else {
             if tls {
-                return Err(cranelift_module::ModuleError::Backend(anyhow::anyhow!("Custom section not supported for TLS")));
+                return Err(cranelift_module::ModuleError::Backend(anyhow::anyhow!(
+                    "Custom section not supported for TLS"
+                )));
             }
             let (seg, sec) = &custom_segment_section.as_ref().unwrap();
             self.object.add_section(