Merge pull request #1083 from bjorn3/fix_lld

Fix lld
2020-09-23 14:02:29 +02:00 · 2020-09-23 14:02:29 +02:00 · a12f60126c
commit a12f60126c
parent e5b2b1ba81 94f11cc3a8
6 changed files with 91 additions and 23 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -44,7 +44,7 @@ checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 [[package]]
 name = "cranelift-bforest"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "cranelift-entity",
 ]
@ -52,7 +52,7 @@ dependencies = [
 [[package]]
 name = "cranelift-codegen"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "byteorder",
 "cranelift-bforest",
@ -70,7 +70,7 @@ dependencies = [
 [[package]]
 name = "cranelift-codegen-meta"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "cranelift-codegen-shared",
 "cranelift-entity",
@ -79,17 +79,17 @@ dependencies = [
 [[package]]
 name = "cranelift-codegen-shared"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"

 [[package]]
 name = "cranelift-entity"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"

 [[package]]
 name = "cranelift-frontend"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "cranelift-codegen",
 "log",
@ -100,7 +100,7 @@ dependencies = [
 [[package]]
 name = "cranelift-module"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "anyhow",
 "cranelift-codegen",
@ -112,7 +112,7 @@ dependencies = [
 [[package]]
 name = "cranelift-native"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "cranelift-codegen",
 "raw-cpuid",
@ -122,7 +122,7 @@ dependencies = [
 [[package]]
 name = "cranelift-object"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "anyhow",
 "cranelift-codegen",
@ -134,7 +134,7 @@ dependencies = [
 [[package]]
 name = "cranelift-simplejit"
 version = "0.66.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#32db4dcbe98098e5be2e457339d6d1946c73225c"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#1fabb051b0436a38f794ca395601dcdcc31d3c18"
 dependencies = [
 "cranelift-codegen",
 "cranelift-module",
--- a/Readme.md
+++ b/Readme.md
@ -70,6 +70,9 @@ function jit_calc() {
    object files when their content should have been changed by a change to cg_clif.</dd>
    <dt>CG_CLIF_DISPLAY_CG_TIME</dt>
    <dd>If "1", display the time it took to perform codegen for a crate</dd>
+    <dt>CG_CLIF_FUNCTION_SECTIONS</dt>
+    <dd>Use a single section for each function. This will often reduce the executable size at the
+        cost of making linking significantly slower.</dd>
 </dl>

 ## Not yet supported
--- a/src/backend.rs
+++ b/src/backend.rs
@ -68,8 +68,17 @@ fn add_debug_section(
        .into_bytes();

        let segment = self.object.segment_name(StandardSegment::Debug).to_vec();
-        let section_id = self.object.add_section(segment, name, SectionKind::Debug);
-        self.object.section_mut(section_id).set_data(data, 1);
+        // FIXME use SHT_X86_64_UNWIND for .eh_frame
+        let section_id = self.object.add_section(segment, name.clone(), if id == SectionId::EhFrame {
+            SectionKind::ReadOnlyData
+        } else {
+            SectionKind::Debug
+        });
+        self.object.section_mut(section_id).set_data(data, if id == SectionId::EhFrame {
+            8
+        } else {
+            1
+        });
        let symbol_id = self.object.section_symbol(section_id);
        (section_id, symbol_id)
    }
@ -95,7 +104,7 @@ fn add_debug_reloc(
                Relocation {
                    offset: u64::from(reloc.offset),
                    symbol,
-                    kind: RelocationKind::Absolute,
+                    kind: reloc.kind,
                    encoding: RelocationEncoding::Generic,
                    size: reloc.size * 8,
                    addend: i64::try_from(symbol_offset).unwrap() + reloc.addend,
@ -186,13 +195,17 @@ pub(crate) fn with_object(sess: &Session, name: &str, f: impl FnOnce(&mut Object
    impl cranelift_module::Backend<Product: AddConstructor + Emit + WriteDebugInfo>;

 pub(crate) fn make_module(sess: &Session, name: String) -> Module<Backend> {
+    let mut builder = ObjectBuilder::new(
+        crate::build_isa(sess, true),
+        name + ".o",
+        cranelift_module::default_libcall_names(),
+    )
+    .unwrap();
+    if std::env::var("CG_CLIF_FUNCTION_SECTIONS").is_ok() {
+        builder.per_function_section(true);
+    }
    let module: Module<ObjectBackend> = Module::new(
-        ObjectBuilder::new(
-            crate::build_isa(sess, true),
-            name + ".o",
-            cranelift_module::default_libcall_names(),
-        )
-        .unwrap(),
+        builder,
    );
    module
 }
--- a/src/constant.rs
+++ b/src/constant.rs
@ -274,7 +274,7 @@ fn data_id_for_alloc_id<B: Backend>(
 ) -> DataId {
    module
        .declare_data(
-            &format!("__alloc_{}", alloc_id.0),
+            &format!("__alloc_{:x}", alloc_id.0),
            Linkage::Local,
            mutability == rustc_hir::Mutability::Mut,
            false,
--- a/src/debuginfo/emit.rs
+++ b/src/debuginfo/emit.rs
@ -46,6 +46,7 @@ pub(crate) struct DebugReloc {
    pub(crate) size: u8,
    pub(crate) name: DebugRelocName,
    pub(crate) addend: i64,
+    pub(crate) kind: object::RelocationKind,
 }

 #[derive(Clone)]
@ -122,14 +123,13 @@ fn write_address(&mut self, address: Address, size: u8) -> Result<()> {
                    size,
                    name: DebugRelocName::Symbol(symbol),
                    addend: addend as i64,
+                    kind: object::RelocationKind::Absolute,
                });
                self.write_udata(0, size)
            }
        }
    }

-    // TODO: implement write_eh_pointer
-
    fn write_offset(&mut self, val: usize, section: SectionId, size: u8) -> Result<()> {
        let offset = self.len() as u32;
        self.relocs.push(DebugReloc {
@ -137,6 +137,7 @@ fn write_offset(&mut self, val: usize, section: SectionId, size: u8) -> Result<(
            size,
            name: DebugRelocName::Section(section),
            addend: val as i64,
+            kind: object::RelocationKind::Absolute,
        });
        self.write_udata(0, size)
    }
@ -153,7 +154,55 @@ fn write_offset_at(
            size,
            name: DebugRelocName::Section(section),
            addend: val as i64,
+            kind: object::RelocationKind::Absolute,
        });
        self.write_udata_at(offset, 0, size)
    }
+
+    fn write_eh_pointer(
+        &mut self,
+        address: Address,
+        eh_pe: gimli::DwEhPe,
+        size: u8,
+    ) -> Result<()> {
+        match address {
+            // Address::Constant arm copied from gimli
+            Address::Constant(val) => {
+                // Indirect doesn't matter here.
+                let val = match eh_pe.application() {
+                    gimli::DW_EH_PE_absptr => val,
+                    gimli::DW_EH_PE_pcrel => {
+                        // TODO: better handling of sign
+                        let offset = self.len() as u64;
+                        offset.wrapping_sub(val)
+                    }
+                    _ => {
+                        return Err(gimli::write::Error::UnsupportedPointerEncoding(eh_pe));
+                    }
+                };
+                self.write_eh_pointer_data(val, eh_pe.format(), size)
+            }
+            Address::Symbol { symbol, addend } => {
+                match eh_pe.application() {
+                    gimli::DW_EH_PE_pcrel => {
+                        let size = match eh_pe.format() {
+                            gimli::DW_EH_PE_sdata4 => 4,
+                            _ => return Err(gimli::write::Error::UnsupportedPointerEncoding(eh_pe)),
+                        };
+                        self.relocs.push(DebugReloc {
+                            offset: self.len() as u32,
+                            size,
+                            name: DebugRelocName::Symbol(symbol),
+                            addend,
+                            kind: object::RelocationKind::Relative,
+                        });
+                        self.write_udata(0, size)
+                    }
+                    _ => {
+                        return Err(gimli::write::Error::UnsupportedPointerEncoding(eh_pe));
+                    }
+                }
+            }
+        }
+    }
 }
--- a/src/debuginfo/unwind.rs
+++ b/src/debuginfo/unwind.rs
@ -16,7 +16,10 @@ impl<'tcx> UnwindContext<'tcx> {
    pub(crate) fn new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa) -> Self {
        let mut frame_table = FrameTable::default();

-        let cie_id = if let Some(cie) = isa.create_systemv_cie() {
+        let cie_id = if let Some(mut cie) = isa.create_systemv_cie() {
+            if isa.flags().is_pic() {
+                cie.fde_address_encoding = gimli::DwEhPe(gimli::DW_EH_PE_pcrel.0 | gimli::DW_EH_PE_sdata4.0);
+            }
            Some(frame_table.add_cie(cie))
        } else {
            None