rustc: add ability to output regular LTO bitcode modules

Adding the option to control from rustc CLI
if the resulted ".o" bitcode module files are with
thinLTO info or regular LTO info.

Allows using "-lto-embed-bitcode=optimized" during linkage
correctly.

Signed-off-by: Ziv Dunkelman <ziv.dunkelman@nextsilicon.com>

10 files changed, 32 insertions, 7 deletions

diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
index 38402e04313..9f793a4ef63 100644
--- a/compiler/rustc_codegen_llvm/src/back/lto.rs
+++ b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -199,7 +199,7 @@ pub(crate) fn run_thin(
 
 pub(crate) fn prepare_thin(module: ModuleCodegen<ModuleLlvm>) -> (String, ThinBuffer) {
     let name = module.name.clone();
-    let buffer = ThinBuffer::new(module.module_llvm.llmod());
+    let buffer = ThinBuffer::new(module.module_llvm.llmod(), true);
     (name, buffer)
 }
 
@@ -709,9 +709,9 @@ unsafe impl Send for ThinBuffer {}
 unsafe impl Sync for ThinBuffer {}
 
 impl ThinBuffer {
-    pub fn new(m: &llvm::Module) -> ThinBuffer {
+    pub fn new(m: &llvm::Module, is_thin: bool) -> ThinBuffer {
         unsafe {
-            let buffer = llvm::LLVMRustThinLTOBufferCreate(m);
+            let buffer = llvm::LLVMRustThinLTOBufferCreate(m, is_thin);
             ThinBuffer(buffer)
         }
     }
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index 2b465ce40e7..534d32e8a90 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -790,7 +790,7 @@ pub(crate) unsafe fn codegen(
             let _timer = cgcx
                 .prof
                 .generic_activity_with_arg("LLVM_module_codegen_make_bitcode", &*module.name);
-            let thin = ThinBuffer::new(llmod);
+            let thin = ThinBuffer::new(llmod, config.emit_thin_lto);
             let data = thin.data();
 
             if let Some(bitcode_filename) = bc_out.file_name() {
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 5ebc2d6139f..1928d47df74 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -2469,7 +2469,7 @@ extern "C" {
     pub fn LLVMRustModuleBufferFree(p: &'static mut ModuleBuffer);
     pub fn LLVMRustModuleCost(M: &Module) -> u64;
 
-    pub fn LLVMRustThinLTOBufferCreate(M: &Module) -> &'static mut ThinLTOBuffer;
+    pub fn LLVMRustThinLTOBufferCreate(M: &Module, is_thin: bool) -> &'static mut ThinLTOBuffer;
     pub fn LLVMRustThinLTOBufferFree(M: &'static mut ThinLTOBuffer);
     pub fn LLVMRustThinLTOBufferPtr(M: &ThinLTOBuffer) -> *const c_char;
     pub fn LLVMRustThinLTOBufferLen(M: &ThinLTOBuffer) -> size_t;
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index c2ac21eec67..ea60f6055f3 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -99,6 +99,7 @@ pub struct ModuleConfig {
     pub emit_ir: bool,
     pub emit_asm: bool,
     pub emit_obj: EmitObj,
+    pub emit_thin_lto: bool,
     pub bc_cmdline: String,
 
     // Miscellaneous flags.  These are mostly copied from command-line
@@ -218,6 +219,7 @@ impl ModuleConfig {
                 false
             ),
             emit_obj,
+            emit_thin_lto: sess.opts.unstable_opts.emit_thin_lto,
             bc_cmdline: sess.target.bitcode_llvm_cmdline.to_string(),
 
             verify_llvm_ir: sess.verify_llvm_ir(),
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 9c0b534798e..9cbbc603cd0 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -734,6 +734,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(drop_tracking, true);
     tracked!(dual_proc_macros, true);
     tracked!(dwarf_version, Some(5));
+    tracked!(emit_thin_lto, false);
     tracked!(fewer_names, Some(true));
     tracked!(force_unstable_if_unmarked, true);
     tracked!(fuel, Some(("abc".to_string(), 99)));
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index 0f4973ebf71..3aac4d83716 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -34,6 +34,7 @@
 #include "llvm/Transforms/Utils/AddDiscriminators.h"
 #include "llvm/Transforms/Utils/FunctionImportUtils.h"
 #include "llvm/LTO/LTO.h"
+#include "llvm/Bitcode/BitcodeWriterPass.h"
 #include "llvm-c/Transforms/PassManagerBuilder.h"
 
 #include "llvm/Transforms/Instrumentation.h"
@@ -1638,13 +1639,17 @@ struct LLVMRustThinLTOBuffer {
 };
 
 extern "C" LLVMRustThinLTOBuffer*
-LLVMRustThinLTOBufferCreate(LLVMModuleRef M) {
+LLVMRustThinLTOBufferCreate(LLVMModuleRef M, bool is_thin) {
   auto Ret = std::make_unique<LLVMRustThinLTOBuffer>();
   {
     raw_string_ostream OS(Ret->data);
     {
       legacy::PassManager PM;
-      PM.add(createWriteThinLTOBitcodePass(OS));
+      if (is_thin) {
+        PM.add(createWriteThinLTOBitcodePass(OS));
+      } else {
+        PM.add(createBitcodeWriterPass(OS));
+      }
       PM.run(*unwrap(M));
     }
   }
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 01ff9e254f7..77c74a30220 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1277,6 +1277,8 @@ options! {
         "version of DWARF debug information to emit (default: 2 or 4, depending on platform)"),
     emit_stack_sizes: bool = (false, parse_bool, [UNTRACKED],
         "emit a section containing stack size metadata (default: no)"),
+    emit_thin_lto: bool = (true, parse_bool, [TRACKED],
+        "emit the bc module with thin LTO info (default: yes)"),
     fewer_names: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "reduce memory use by retaining fewer names within compilation artifacts (LLVM-IR) \
         (default: no)"),
diff --git a/src/test/run-make-fulldeps/issue-84395-lto-embed-bitcode/Makefile b/src/test/run-make-fulldeps/issue-84395-lto-embed-bitcode/Makefile
new file mode 100644
index 00000000000..157edb20c30
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue-84395-lto-embed-bitcode/Makefile
@@ -0,0 +1,11 @@
+# needs-matching-clang
+
+# This test makes sure the embed bitcode in elf created with
+# lto-embed-bitcode=optimized is valid llvm BC module.
+
+-include ../../run-make-fulldeps/tools.mk
+
+all:
+	$(RUSTC) test.rs --target $(TARGET) -Clink-arg=-fuse-ld=lld -Clinker-plugin-lto -Clinker=$(CLANG) -Clink-arg=-Wl,--plugin-opt=-lto-embed-bitcode=optimized -Zemit-thin-lto=no
+	$(LLVM_BIN_DIR)/objcopy --dump-section .llvmbc=$(TMPDIR)/test.bc $(TMPDIR)/test
+	$(LLVM_BIN_DIR)/llvm-dis $(TMPDIR)/test.bc
diff --git a/src/test/run-make-fulldeps/issue-84395-lto-embed-bitcode/test.rs b/src/test/run-make-fulldeps/issue-84395-lto-embed-bitcode/test.rs
new file mode 100644
index 00000000000..47ad8c63411
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue-84395-lto-embed-bitcode/test.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello World!");
+}
diff --git a/src/test/rustdoc-ui/z-help.stdout b/src/test/rustdoc-ui/z-help.stdout
index 7296b35788a..54c4de0e031 100644
--- a/src/test/rustdoc-ui/z-help.stdout
+++ b/src/test/rustdoc-ui/z-help.stdout
@@ -35,6 +35,7 @@
     -Z                       dump-mir-spanview=val -- in addition to `.mir` files, create `.html` files to view spans for all `statement`s (including terminators), only `terminator` spans, or computed `block` spans (one span encompassing a block's terminator and all statements). If `-Z instrument-coverage` is also enabled, create an additional `.html` file showing the computed coverage spans.
     -Z                           dwarf-version=val -- version of DWARF debug information to emit (default: 2 or 4, depending on platform)
     -Z                        emit-stack-sizes=val -- emit a section containing stack size metadata (default: no)
+    -Z                           emit-thin-lto=val -- emit the bc module with thin LTO info (default: yes)
     -Z                             fewer-names=val -- reduce memory use by retaining fewer names within compilation artifacts (LLVM-IR) (default: no)
     -Z              force-unstable-if-unmarked=val -- force all crates to be `rustc_private` unstable (default: no)
     -Z                                    fuel=val -- set the optimization fuel quota for a crate