Update libunwind to LLVM 19.1.4 (#22934)

Other than these two PRs I submitted to upstream LLVM, all other changes are unrelated upstream changes. llvm/llvm-project#92192 llvm/llvm-project#92840 This PR was created by running https://github.com/emscripten-core/emscripten/blob/main/system/lib/update_libunwind.py script.
emscripten-core · Nov 20, 2024 · 119a427 · 119a427
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diff --git a/ChangeLog.md b/ChangeLog.md
@@ -20,6 +20,7 @@ See docs/process.md for more on how version tagging works.
 
 3.1.73 (in development)
 -----------------------
+- libunwind was updated to LLVM 19.1.4. (#22394)
 
 3.1.72 - 11/19/24
 -----------------

diff --git a/system/lib/libunwind/include/__libunwind_config.h b/system/lib/libunwind/include/__libunwind_config.h
@@ -180,6 +180,10 @@
 #endif
 #define _LIBUNWIND_HIGHEST_DWARF_REGISTER                                      \
   _LIBUNWIND_HIGHEST_DWARF_REGISTER_LOONGARCH
+#elif defined(__wasm__)
+// Unused
+#define _LIBUNWIND_CONTEXT_SIZE 0
+#define _LIBUNWIND_CURSOR_SIZE 0
 # else
 #  error "Unsupported architecture."
 # endif

diff --git a/system/lib/libunwind/include/mach-o/compact_unwind_encoding.modulemap b/system/lib/libunwind/include/mach-o/compact_unwind_encoding.modulemap
diff --git a/system/lib/libunwind/readme.txt b/system/lib/libunwind/readme.txt
@@ -1,14 +1,14 @@
 llvm's libunwind
 ----------------
 
-These files are from the llvm-project based on release 17.0.4.
+These files are from the llvm-project based on release 19.1.4.
 
 We maintain a local fork of llvm-project that contains any emscripten
 specific patches:
 
   https://github.com/emscripten-core/llvm-project
 
-The current patch is based on the emscripten-libs-17 branch.
+The current patch is based on the emscripten-libs-19 branch.
 
 Update Instructions
 -------------------
@@ -20,4 +20,4 @@ Modifications
 
 For a list of changes from upstream see the libunwind files that are part of:
 
-https://github.com/llvm/llvm-project/compare/llvmorg-17.0.4...emscripten-core:emscripten-libs-17
+https://github.com/llvm/llvm-project/compare/llvmorg-19.1.4...emscripten-core:emscripten-libs-19
diff --git a/system/lib/libunwind/src/Registers.hpp b/system/lib/libunwind/src/Registers.hpp
@@ -1815,6 +1815,13 @@ inline const char *Registers_ppc64::getRegisterName(int regNum) {
 /// process.
 class _LIBUNWIND_HIDDEN Registers_arm64;
 extern "C" void __libunwind_Registers_arm64_jumpto(Registers_arm64 *);
+
+#if defined(_LIBUNWIND_USE_GCS)
+extern "C" void *__libunwind_cet_get_jump_target() {
+  return reinterpret_cast<void *>(&__libunwind_Registers_arm64_jumpto);
+}
+#endif
+
 class _LIBUNWIND_HIDDEN Registers_arm64 {
 public:
   Registers_arm64();

diff --git a/system/lib/libunwind/src/UnwindCursor.hpp b/system/lib/libunwind/src/UnwindCursor.hpp
@@ -36,7 +36,6 @@
 #include <errno.h>
 #include <signal.h>
 #include <sys/syscall.h>
-#include <sys/uio.h>
 #include <unistd.h>
 #define _LIBUNWIND_CHECK_LINUX_SIGRETURN 1
 #endif
@@ -472,7 +471,7 @@ class _LIBUNWIND_HIDDEN AbstractUnwindCursor {
   }
 #endif
 
-#if defined(_LIBUNWIND_USE_CET)
+#if defined(_LIBUNWIND_USE_CET) || defined(_LIBUNWIND_USE_GCS)
   virtual void *get_registers() {
     _LIBUNWIND_ABORT("get_registers not implemented");
   }
@@ -955,7 +954,7 @@ class UnwindCursor : public AbstractUnwindCursor{
   virtual uintptr_t getDataRelBase();
 #endif
 
-#if defined(_LIBUNWIND_USE_CET)
+#if defined(_LIBUNWIND_USE_CET) || defined(_LIBUNWIND_USE_GCS)
   virtual void *get_registers() { return &_registers; }
 #endif
 
@@ -2416,7 +2415,7 @@ int UnwindCursor<A, R>::stepWithTBTable(pint_t pc, tbtable *TBTable,
     }
 
     // Reset LR in the current context.
-    newRegisters.setLR(NULL);
+    newRegisters.setLR(static_cast<uintptr_t>(NULL));
 
     _LIBUNWIND_TRACE_UNWINDING(
         "Extract info from lastStack=%p, returnAddress=%p",
@@ -2590,6 +2589,15 @@ void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
     --pc;
 #endif
 
+#if !(defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)) &&            \
+    !defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
+  // In case of this is frame of signal handler, the IP saved in the signal
+  // handler points to first non-executed instruction, while FDE/CIE expects IP
+  // to be after the first non-executed instruction.
+  if (_isSignalFrame)
+    ++pc;
+#endif
+
   // Ask address space object to find unwind sections for this pc.
   UnwindInfoSections sects;
   if (_addressSpace.findUnwindSections(pc, sects)) {
@@ -2997,7 +3005,7 @@ bool UnwindCursor<A, R>::isReadableAddr(const pint_t addr) const {
 }
 #endif
 
-#if defined(_LIBUNWIND_USE_CET)
+#if defined(_LIBUNWIND_USE_CET) || defined(_LIBUNWIND_USE_GCS)
 extern "C" void *__libunwind_cet_get_registers(unw_cursor_t *cursor) {
   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
   return co->get_registers();

diff --git a/system/lib/libunwind/src/UnwindLevel1.c b/system/lib/libunwind/src/UnwindLevel1.c
@@ -31,7 +31,8 @@
 #include "libunwind_ext.h"
 #include "unwind.h"
 
-#if !defined(_LIBUNWIND_ARM_EHABI) && !defined(__USING_SJLJ_EXCEPTIONS__)
+#if !defined(_LIBUNWIND_ARM_EHABI) && !defined(__USING_SJLJ_EXCEPTIONS__) &&   \
+    !defined(__wasm__)
 
 #ifndef _LIBUNWIND_SUPPORT_SEH_UNWIND
 
@@ -43,7 +44,7 @@
 // _LIBUNWIND_POP_CET_SSP is used to adjust CET shadow stack pointer and we
 // directly jump to __libunwind_Registers_x86/x86_64_jumpto instead of using
 // a regular function call to avoid pushing to CET shadow stack again.
-#if !defined(_LIBUNWIND_USE_CET)
+#if !defined(_LIBUNWIND_USE_CET) && !defined(_LIBUNWIND_USE_GCS)
 #define __unw_phase2_resume(cursor, fn)                                        \
   do {                                                                         \
     (void)fn;                                                                  \
@@ -71,6 +72,19 @@
     __asm__ volatile("jmpq *%%rdx\n\t" :: "D"(cetRegContext),                  \
                      "d"(cetJumpAddress));                                     \
   } while (0)
+#elif defined(_LIBUNWIND_TARGET_AARCH64)
+#define __cet_ss_step_size 8
+#define __unw_phase2_resume(cursor, fn)                                        \
+  do {                                                                         \
+    _LIBUNWIND_POP_CET_SSP((fn));                                              \
+    void *cetRegContext = __libunwind_cet_get_registers((cursor));             \
+    void *cetJumpAddress = __libunwind_cet_get_jump_target();                  \
+    __asm__ volatile("mov x0, %0\n\t"                                          \
+                     "br %1\n\t"                                               \
+                     :                                                         \
+                     : "r"(cetRegContext), "r"(cetJumpAddress)                 \
+                     : "x0");                                                  \
+  } while (0)
 #endif
 
 static _Unwind_Reason_Code
@@ -169,6 +183,10 @@ unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *except
 }
 extern int __unw_step_stage2(unw_cursor_t *);
 
+#if defined(_LIBUNWIND_USE_GCS)
+// Enable the GCS target feature to permit gcspop instructions to be used.
+__attribute__((target("gcs")))
+#endif
 static _Unwind_Reason_Code
 unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) {
   __unw_init_local(cursor, uc);
@@ -179,8 +197,12 @@ unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *except
   // uc is initialized by __unw_getcontext in the parent frame. The first stack
   // frame walked is unwind_phase2.
   unsigned framesWalked = 1;
-#ifdef _LIBUNWIND_USE_CET
+#if defined(_LIBUNWIND_USE_CET)
   unsigned long shadowStackTop = _get_ssp();
+#elif defined(_LIBUNWIND_USE_GCS)
+  unsigned long shadowStackTop = 0;
+  if (__chkfeat(_CHKFEAT_GCS))
+    shadowStackTop = (unsigned long)__gcspr();
 #endif
   // Walk each frame until we reach where search phase said to stop.
   while (true) {
@@ -237,7 +259,7 @@ unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *except
 // against return address stored in CET shadow stack, if the 2 addresses don't
 // match, it means return address in normal stack has been corrupted, we return
 // _URC_FATAL_PHASE2_ERROR.
-#ifdef _LIBUNWIND_USE_CET
+#if defined(_LIBUNWIND_USE_CET) || defined(_LIBUNWIND_USE_GCS)
     if (shadowStackTop != 0) {
       unw_word_t retInNormalStack;
       __unw_get_reg(cursor, UNW_REG_IP, &retInNormalStack);
@@ -305,6 +327,10 @@ unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *except
   return _URC_FATAL_PHASE2_ERROR;
 }
 
+#if defined(_LIBUNWIND_USE_GCS)
+// Enable the GCS target feature to permit gcspop instructions to be used.
+__attribute__((target("gcs")))
+#endif
 static _Unwind_Reason_Code
 unwind_phase2_forced(unw_context_t *uc, unw_cursor_t *cursor,
                      _Unwind_Exception *exception_object,

diff --git a/system/lib/libunwind/src/UnwindRegistersRestore.S b/system/lib/libunwind/src/UnwindRegistersRestore.S
@@ -20,7 +20,7 @@
   .text
 #endif
 
-#if !defined(__USING_SJLJ_EXCEPTIONS__)
+#if !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__)
 
 #if defined(__i386__)
 DEFINE_LIBUNWIND_FUNCTION(__libunwind_Registers_x86_jumpto)
@@ -629,6 +629,10 @@ Lnovec:
 
 #elif defined(__aarch64__)
 
+#if defined(__ARM_FEATURE_GCS_DEFAULT)
+.arch_extension gcs
+#endif
+
 //
 // extern "C" void __libunwind_Registers_arm64_jumpto(Registers_arm64 *);
 //
@@ -680,6 +684,16 @@ DEFINE_LIBUNWIND_FUNCTION(__libunwind_Registers_arm64_jumpto)
   ldr    x16,     [x0, #0x0F8]
   ldp    x0, x1,  [x0, #0x000]  // restore x0,x1
   mov    sp,x16                 // restore sp
+#if defined(__ARM_FEATURE_GCS_DEFAULT)
+  // If GCS is enabled we need to push the address we're returning to onto the
+  // GCS stack. We can't just return using br, as there won't be a BTI landing
+  // pad instruction at the destination.
+  mov      x16, #1
+  chkfeat  x16
+  cbnz     x16, Lnogcs
+  gcspushm x30
+Lnogcs:
+#endif
   ret    x30                    // jump to pc
 
 #elif defined(__arm__) && !defined(__APPLE__)
@@ -1232,7 +1246,7 @@ DEFINE_LIBUNWIND_FUNCTION(_ZN9libunwind19Registers_loongarch6jumptoEv)
 
 #endif
 
-#endif /* !defined(__USING_SJLJ_EXCEPTIONS__) */
+#endif /* !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__) */
 
 NO_EXEC_STACK_DIRECTIVE
 
diff --git a/system/lib/libunwind/src/UnwindRegistersSave.S b/system/lib/libunwind/src/UnwindRegistersSave.S
@@ -20,7 +20,7 @@
     .text
 #endif
 
-#if !defined(__USING_SJLJ_EXCEPTIONS__)
+#if !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__)
 
 #if defined(__i386__)
 
@@ -1177,6 +1177,6 @@ DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext)
 
   WEAK_ALIAS(__unw_getcontext, unw_getcontext)
 
-#endif /* !defined(__USING_SJLJ_EXCEPTIONS__) */
+#endif /* !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__) */
 
 NO_EXEC_STACK_DIRECTIVE
diff --git a/system/lib/libunwind/src/assembly.h b/system/lib/libunwind/src/assembly.h
@@ -82,7 +82,22 @@
 #define PPC64_OPD2
 #endif
 
-#if defined(__aarch64__) && defined(__ARM_FEATURE_BTI_DEFAULT)
+#if defined(__aarch64__)
+#if defined(__ARM_FEATURE_GCS_DEFAULT) && defined(__ARM_FEATURE_BTI_DEFAULT)
+// Set BTI, PAC, and GCS gnu property bits
+#define GNU_PROPERTY 7
+// We indirectly branch to __libunwind_Registers_arm64_jumpto from
+// __unw_phase2_resume, so we need to use bti jc.
+#define AARCH64_BTI bti jc
+#elif defined(__ARM_FEATURE_GCS_DEFAULT)
+// Set GCS gnu property bit
+#define GNU_PROPERTY 4
+#elif defined(__ARM_FEATURE_BTI_DEFAULT)
+// Set BTI and PAC gnu property bits
+#define GNU_PROPERTY 3
+#define AARCH64_BTI bti c
+#endif
+#ifdef GNU_PROPERTY
   .pushsection ".note.gnu.property", "a" SEPARATOR                             \
   .balign 8 SEPARATOR                                                          \
   .long 4 SEPARATOR                                                            \
@@ -91,12 +106,12 @@
   .asciz "GNU" SEPARATOR                                                       \
   .long 0xc0000000 SEPARATOR /* GNU_PROPERTY_AARCH64_FEATURE_1_AND */          \
   .long 4 SEPARATOR                                                            \
-  .long 3 SEPARATOR /* GNU_PROPERTY_AARCH64_FEATURE_1_BTI AND */               \
-                    /* GNU_PROPERTY_AARCH64_FEATURE_1_PAC */                   \
+  .long GNU_PROPERTY SEPARATOR                                                 \
   .long 0 SEPARATOR                                                            \
   .popsection SEPARATOR
-#define AARCH64_BTI  bti c
-#else
+#endif
+#endif
+#if !defined(AARCH64_BTI)
 #define AARCH64_BTI
 #endif
 

diff --git a/system/lib/libunwind/src/cet_unwind.h b/system/lib/libunwind/src/cet_unwind.h
@@ -35,6 +35,28 @@
   } while (0)
 #endif
 
+// On AArch64 we use _LIBUNWIND_USE_GCS to indicate that GCS is supported. We
+// need to guard any use of GCS instructions with __chkfeat though, as GCS may
+// not be enabled.
+#if defined(_LIBUNWIND_TARGET_AARCH64) && defined(__ARM_FEATURE_GCS_DEFAULT)
+#include <arm_acle.h>
+
+// We can only use GCS if arm_acle.h defines the GCS intrinsics.
+#ifdef _CHKFEAT_GCS
+#define _LIBUNWIND_USE_GCS 1
+#endif
+
+#define _LIBUNWIND_POP_CET_SSP(x)                                              \
+  do {                                                                         \
+    if (__chkfeat(_CHKFEAT_GCS)) {                                             \
+      unsigned tmp = (x);                                                      \
+      while (tmp--)                                                            \
+        __gcspopm();                                                           \
+    }                                                                          \
+  } while (0)
+
+#endif
+
 extern void *__libunwind_cet_get_registers(unw_cursor_t *);
 extern void *__libunwind_cet_get_jump_target(void);
 

diff --git a/system/lib/libunwind/src/libunwind.cpp b/system/lib/libunwind/src/libunwind.cpp
@@ -26,7 +26,7 @@
 #include <sanitizer/asan_interface.h>
 #endif
 
-#if !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__WASM_EXCEPTIONS__)
+#if !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__)
 #include "AddressSpace.hpp"
 #include "UnwindCursor.hpp"
 
@@ -347,8 +347,7 @@ void __unw_remove_dynamic_eh_frame_section(unw_word_t eh_frame_start) {
 }
 
 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
-#endif // !defined(__USING_SJLJ_EXCEPTIONS__) &&
-       // !defined(__WASM_EXCEPTIONS__)
+#endif // !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__)
 
 #ifdef __APPLE__
-Original file line number
+Diff line change
@@ Expand Up / @@ -20,6 +20,7 @@ See docs/process.md for more on how version tagging works. @@
 .1.73 (in development)
     -----------------------
+    - libunwind was updated to LLVM 19.1.4. (#22394)
 .1.72 - 11/19/24
     -----------------
@@ Expand Down @@