Pass debuginfo_compression through FFI as an enum

Author: Zalathar

compiler/rustc_codegen_llvm/src/back/owned_target_machine.rs

@@ -36,7 +36,7 @@ impl OwnedTargetMachine {
  use_init_array: bool,
  split_dwarf_file: &CStr,
  output_obj_file: &CStr,
- debug_info_compression: &CStr,
+ debug_info_compression: llvm::CompressionKind,
  use_emulated_tls: bool,
  use_wasm_eh: bool,
  ) -> Result<Self, LlvmError<'static>> {
@@ -62,7 +62,7 @@ impl OwnedTargetMachine {
  use_init_array,
  split_dwarf_file.as_ptr(),
  output_obj_file.as_ptr(),
- debug_info_compression.as_ptr(),
+ debug_info_compression,
  use_emulated_tls,
  use_wasm_eh,
  )

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -6,9 +6,6 @@ use std::sync::Arc;
 use std::{fs, slice, str};
 
 use libc::{c_char, c_int, c_void, size_t};
-use llvm::{
- LLVMRustLLVMHasZlibCompressionForDebugSymbols, LLVMRustLLVMHasZstdCompressionForDebugSymbols,
-};
 use rustc_codegen_ssa::back::link::ensure_removed;
 use rustc_codegen_ssa::back::versioned_llvm_target;
 use rustc_codegen_ssa::back::write::{
@@ -252,21 +249,25 @@ pub(crate) fn target_machine_factory(
 
  let use_emulated_tls = matches!(sess.tls_model(), TlsModel::Emulated);
 
- let debuginfo_compression = sess.opts.debuginfo_compression.to_string();
- match sess.opts.debuginfo_compression {
- rustc_session::config::DebugInfoCompression::Zlib => {
- if !unsafe { LLVMRustLLVMHasZlibCompressionForDebugSymbols() } {
+ let debuginfo_compression = match sess.opts.debuginfo_compression {
+ config::DebugInfoCompression::None => llvm::CompressionKind::None,
+ config::DebugInfoCompression::Zlib => {
+ if llvm::LLVMRustLLVMHasZlibCompression() {
+ llvm::CompressionKind::Zlib
+ } else {
  sess.dcx().emit_warn(UnknownCompression { algorithm: "zlib" });
+ llvm::CompressionKind::None
  }
  }
- rustc_session::config::DebugInfoCompression::Zstd => {
- if !unsafe { LLVMRustLLVMHasZstdCompressionForDebugSymbols() } {
+ config::DebugInfoCompression::Zstd => {
+ if llvm::LLVMRustLLVMHasZstdCompression() {
+ llvm::CompressionKind::Zstd
+ } else {
  sess.dcx().emit_warn(UnknownCompression { algorithm: "zstd" });
+ llvm::CompressionKind::None
  }
  }
- rustc_session::config::DebugInfoCompression::None => {}
  };
- let debuginfo_compression = SmallCStr::new(&debuginfo_compression);
 
  let file_name_display_preference =
  sess.filename_display_preference(RemapPathScopeComponents::DEBUGINFO);
@@ -310,7 +311,7 @@ pub(crate) fn target_machine_factory(
  use_init_array,
  &split_dwarf_file,
  &output_obj_file,
- &debuginfo_compression,
+ debuginfo_compression,
  use_emulated_tls,
  use_wasm_eh,
  )

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -677,6 +677,15 @@ pub(crate) enum Opcode {
  CatchSwitch = 65,
 }
 
+/// Must match the layout of `LLVMRustCompressionKind`.
+#[derive(Copy, Clone)]
+#[repr(C)]
+pub(crate) enum CompressionKind {
+ None = 0,
+ Zlib = 1,
+ Zstd = 2,
+}
+
 unsafe extern "C" {
  type Opaque;
 }
@@ -2328,7 +2337,7 @@ unsafe extern "C" {
  UseInitArray: bool,
  SplitDwarfFile: *const c_char,
  OutputObjFile: *const c_char,
- DebugInfoCompression: *const c_char,
+ DebugInfoCompression: CompressionKind,
  UseEmulatedTls: bool,
  UseWasmEH: bool,
  ) -> *mut TargetMachine;
@@ -2516,9 +2525,8 @@ unsafe extern "C" {
 
  pub(crate) fn LLVMRustGetElementTypeArgIndex(CallSite: &Value) -> i32;
 
- pub(crate) fn LLVMRustLLVMHasZlibCompressionForDebugSymbols() -> bool;
-
- pub(crate) fn LLVMRustLLVMHasZstdCompressionForDebugSymbols() -> bool;
+ pub(crate) safe fn LLVMRustLLVMHasZlibCompression() -> bool;
+ pub(crate) safe fn LLVMRustLLVMHasZstdCompression() -> bool;
 
  pub(crate) fn LLVMRustGetSymbols(
  buf_ptr: *const u8,

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -224,6 +224,31 @@ static FloatABI::ABIType fromRust(LLVMRustFloatABI RustFloatAbi) {
  report_fatal_error("Bad FloatABI.");
 }
 
+// Must match the layout of `rustc_codegen_llvm::llvm::ffi::CompressionKind`.
+enum class LLVMRustCompressionKind {
+ None = 0,
+ Zlib = 1,
+ Zstd = 2,
+};
+
+static llvm::DebugCompressionType fromRust(LLVMRustCompressionKind Kind) {
+ switch (Kind) {
+ case LLVMRustCompressionKind::None:
+ return llvm::DebugCompressionType::None;
+ case LLVMRustCompressionKind::Zlib:
+ if (!llvm::compression::zlib::isAvailable()) {
+ report_fatal_error("LLVMRustCompressionKind::Zlib not available");
+ }
+ return llvm::DebugCompressionType::Zlib;
+ case LLVMRustCompressionKind::Zstd:
+ if (!llvm::compression::zstd::isAvailable()) {
+ report_fatal_error("LLVMRustCompressionKind::Zstd not available");
+ }
+ return llvm::DebugCompressionType::Zstd;
+ }
+ report_fatal_error("bad LLVMRustCompressionKind");
+}
+
 extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM,
  RustStringRef OutStr) {
  ArrayRef<SubtargetSubTypeKV> CPUTable =
@@ -271,7 +296,8 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
  bool TrapUnreachable, bool Singlethread, bool VerboseAsm,
  bool EmitStackSizeSection, bool RelaxELFRelocations, bool UseInitArray,
  const char *SplitDwarfFile, const char *OutputObjFile,
- const char *DebugInfoCompression, bool UseEmulatedTls, bool UseWasmEH) {
+ LLVMRustCompressionKind DebugInfoCompression, bool UseEmulatedTls,
+ bool UseWasmEH) {
 
  auto OptLevel = fromRust(RustOptLevel);
  auto RM = fromRust(RustReloc);
@@ -307,16 +333,10 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
  if (OutputObjFile) {
  Options.ObjectFilenameForDebug = OutputObjFile;
  }
- if (!strcmp("zlib", DebugInfoCompression) &&
- llvm::compression::zlib::isAvailable()) {
- Options.MCOptions.CompressDebugSections = DebugCompressionType::Zlib;
- } else if (!strcmp("zstd", DebugInfoCompression) &&
- llvm::compression::zstd::isAvailable()) {
- Options.MCOptions.CompressDebugSections = DebugCompressionType::Zstd;
- } else if (!strcmp("none", DebugInfoCompression)) {
- Options.MCOptions.CompressDebugSections = DebugCompressionType::None;
- }
-
+ // To avoid fatal errors, make sure the Rust-side code only passes a
+ // compression kind that is known to be supported by this build of LLVM, via
+ // `LLVMRustLLVMHasZlibCompression` and `LLVMRustLLVMHasZstdCompression`.
+ Options.MCOptions.CompressDebugSections = fromRust(DebugInfoCompression);
  Options.MCOptions.X86RelaxRelocations = RelaxELFRelocations;
  Options.UseInitArray = UseInitArray;
  Options.EmulatedTLS = UseEmulatedTls;

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -1640,11 +1640,11 @@ extern "C" bool LLVMRustIsNonGVFunctionPointerTy(LLVMValueRef V) {
  return false;
 }
 
-extern "C" bool LLVMRustLLVMHasZlibCompressionForDebugSymbols() {
+extern "C" bool LLVMRustLLVMHasZlibCompression() {
  return llvm::compression::zlib::isAvailable();
 }
 
-extern "C" bool LLVMRustLLVMHasZstdCompressionForDebugSymbols() {
+extern "C" bool LLVMRustLLVMHasZstdCompression() {
  return llvm::compression::zstd::isAvailable();
 }
 

compiler/rustc_session/src/config.rs

@@ -583,17 +583,6 @@ pub enum DebugInfoCompression {
  Zstd,
 }
 
-impl ToString for DebugInfoCompression {
- fn to_string(&self) -> String {
- match self {
- DebugInfoCompression::None => "none",
- DebugInfoCompression::Zlib => "zlib",
- DebugInfoCompression::Zstd => "zstd",
- }
- .to_owned()
- }
-}
-
 #[derive(Clone, Copy, Debug, PartialEq, Hash)]
 pub enum MirStripDebugInfo {
  None,