emscripten-core · aheejin · Jul 20, 2026 · Jul 3, 2026 · Jul 3, 2026 · Jul 17, 2026
diff --git a/ChangeLog.md b/ChangeLog.md
@@ -24,6 +24,7 @@ See docs/process.md for more on how version tagging works.
   #27339, #27338, #27340, #27347)
 - Removed legacy JS library symbols symbols: `$ALLOC_NORMAL`, `$ALLOC_STACK`,
   and `$allocate`. (#27378)
+- llvm-libc was updated to LLVM 22.1.8. (#27374)
 
 6.0.3 - 07/13/26
 ----------------

diff --git a/system/lib/llvm-libc/README.md b/system/lib/llvm-libc/README.md
@@ -1,14 +1,14 @@
 llvm's libc
 -----------
 
-These files are from the llvm-project based on release 21.1.8.
+These files are from the llvm-project based on release 22.1.8.
 
 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-21 branch.
+The current patch is based on the emscripten-libs-22 branch.
 
 Currently in production, we do not use LLVM's libc directly yet, but libcxx uses
 a subset of headers from libc. So libcxx directly depends on the following
@@ -32,6 +32,6 @@ Run `system/lib/update_llvm_libc.py path/to/llvm-project`
 Modifications
 -------------
 
-For a list of changes from upstream see the libcxx files that are part of:
+For a list of changes from upstream see the libc files that are part of:
 
-https://github.com/llvm/llvm-project/compare/llvmorg-21.1.8...emscripten-core:emscripten-libs-21
+https://github.com/llvm/llvm-project/compare/llvmorg-22.1.8...emscripten-core:emscripten-libs-22
diff --git a/system/lib/llvm-libc/config/baremetal/aarch64/entrypoints.txt b/system/lib/llvm-libc/config/baremetal/aarch64/entrypoints.txt
@@ -124,8 +124,19 @@ set(TARGET_LIBC_ENTRYPOINTS
 
     # stdio.h entrypoints
     libc.src.stdio.asprintf
+    libc.src.stdio.feof
+    libc.src.stdio.ferror
+    libc.src.stdio.fgetc
+    libc.src.stdio.fgets
+    libc.src.stdio.fprintf
+    libc.src.stdio.fputc
+    libc.src.stdio.fputs
+    libc.src.stdio.fread
+    libc.src.stdio.fscanf
+    libc.src.stdio.fwrite
     libc.src.stdio.getchar
     libc.src.stdio.printf
+    libc.src.stdio.putc
     libc.src.stdio.putchar
     libc.src.stdio.puts
     libc.src.stdio.remove
@@ -134,6 +145,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.sprintf
     libc.src.stdio.sscanf
     libc.src.stdio.vasprintf
+    libc.src.stdio.vfprintf
+    libc.src.stdio.vfscanf
     libc.src.stdio.vprintf
     libc.src.stdio.vscanf
     libc.src.stdio.vsnprintf
@@ -218,6 +231,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.abort
     libc.src.stdlib.abs
     libc.src.stdlib.aligned_alloc
+    libc.src.stdlib.atexit
     libc.src.stdlib.atof
     libc.src.stdlib.atoi
     libc.src.stdlib.atol
@@ -268,6 +282,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.time.difftime
     libc.src.time.gmtime
     libc.src.time.gmtime_r
+    libc.src.time.localtime
+    libc.src.time.localtime_r
     libc.src.time.mktime
     libc.src.time.strftime
     libc.src.time.strftime_l
@@ -317,8 +333,10 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.fenv.feupdateenv
 
     # math.h entrypoints
+    libc.src.math.acos
     libc.src.math.acosf
     libc.src.math.acoshf
+    libc.src.math.asin
     libc.src.math.asinf
     libc.src.math.asinhf
     libc.src.math.atan2
@@ -754,6 +772,90 @@ if(LIBC_TYPES_HAS_FLOAT128)
   )
 endif()
 
+list(APPEND TARGET_LIBM_ENTRYPOINTS
+  # bfloat16 entrypoints
+  libc.src.math.bf16add
+  libc.src.math.bf16addf
+  libc.src.math.bf16addl
+  libc.src.math.bf16div
+  libc.src.math.bf16divf
+  libc.src.math.bf16divl
+  libc.src.math.bf16fma
+  libc.src.math.bf16fmaf
+  libc.src.math.bf16fmal
+  libc.src.math.bf16mul
+  libc.src.math.bf16mulf
+  libc.src.math.bf16mull
+  libc.src.math.bf16sub
+  libc.src.math.bf16subf
+  libc.src.math.bf16subl
+  libc.src.math.canonicalizebf16
+  libc.src.math.ceilbf16
+  libc.src.math.copysignbf16
+  libc.src.math.fabsbf16
+  libc.src.math.fdimbf16
+  libc.src.math.floorbf16
+  libc.src.math.fmaxbf16
+  libc.src.math.fmaximumbf16
+  libc.src.math.fmaximum_magbf16
+  libc.src.math.fmaximum_mag_numbf16
+  libc.src.math.fmaximum_numbf16
+  libc.src.math.fminbf16
+  libc.src.math.fminimumbf16
+  libc.src.math.fminimum_magbf16
+  libc.src.math.fminimum_mag_numbf16
+  libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
+  libc.src.math.frexpbf16
+  libc.src.math.fromfpbf16
+  libc.src.math.fromfpxbf16
+  libc.src.math.getpayloadbf16
+  libc.src.math.ilogbbf16
+  libc.src.math.iscanonicalbf16
+  libc.src.math.issignalingbf16
+  libc.src.math.ldexpbf16
+  libc.src.math.llogbbf16
+  libc.src.math.llrintbf16
+  libc.src.math.llroundbf16
+  libc.src.math.log_bf16
+  libc.src.math.logbbf16
+  libc.src.math.lrintbf16
+  libc.src.math.lroundbf16
+  libc.src.math.modfbf16
+  libc.src.math.nanbf16
+  libc.src.math.nearbyintbf16
+  libc.src.math.nextafterbf16
+  libc.src.math.nextdownbf16
+  libc.src.math.nexttowardbf16
+  libc.src.math.nextupbf16
+  libc.src.math.remainderbf16
+  libc.src.math.remquobf16
+  libc.src.math.rintbf16
+  libc.src.math.roundbf16
+  libc.src.math.roundevenbf16
+  libc.src.math.scalblnbf16
+  libc.src.math.scalbnbf16
+  libc.src.math.setpayloadbf16
+  libc.src.math.setpayloadsigbf16
+  libc.src.math.sqrtbf16
+  libc.src.math.truncbf16
+  libc.src.math.totalorderbf16
+  libc.src.math.totalordermagbf16
+  libc.src.math.ufromfpbf16
+  libc.src.math.ufromfpxbf16
+)
+
+if(LIBC_TYPES_HAS_FLOAT128)
+  list(APPEND TARGET_LIBM_ENTRYPOINTS
+    # math.h C++23 mixed bfloat16 and _Float128 entrypoints
+    libc.src.math.bf16addf128
+    libc.src.math.bf16divf128
+    libc.src.math.bf16fmaf128
+    libc.src.math.bf16mulf128
+    libc.src.math.bf16subf128
+  )
+endif()
+
 if(LIBC_COMPILER_HAS_FIXED_POINT)
   list(APPEND TARGET_LIBM_ENTRYPOINTS
     # stdfix.h _Fract and _Accum entrypoints

diff --git a/system/lib/llvm-libc/config/baremetal/aarch64/headers.txt b/system/lib/llvm-libc/config/baremetal/aarch64/headers.txt
@@ -2,6 +2,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.assert
     libc.include.complex
     libc.include.ctype
+    libc.include.elf
     libc.include.errno
     libc.include.features
     libc.include.fenv

diff --git a/system/lib/llvm-libc/config/baremetal/arm/entrypoints.txt b/system/lib/llvm-libc/config/baremetal/arm/entrypoints.txt
@@ -124,8 +124,19 @@ set(TARGET_LIBC_ENTRYPOINTS
 
     # stdio.h entrypoints
     libc.src.stdio.asprintf
+    libc.src.stdio.feof
+    libc.src.stdio.ferror
+    libc.src.stdio.fgetc
+    libc.src.stdio.fgets
+    libc.src.stdio.fprintf
+    libc.src.stdio.fputc
+    libc.src.stdio.fputs
+    libc.src.stdio.fread
+    libc.src.stdio.fscanf
+    libc.src.stdio.fwrite
     libc.src.stdio.getchar
     libc.src.stdio.printf
+    libc.src.stdio.putc
     libc.src.stdio.putchar
     libc.src.stdio.puts
     libc.src.stdio.remove
@@ -134,6 +145,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.sprintf
     libc.src.stdio.sscanf
     libc.src.stdio.vasprintf
+    libc.src.stdio.vfprintf
+    libc.src.stdio.vfscanf
     libc.src.stdio.vprintf
     libc.src.stdio.vscanf
     libc.src.stdio.vsnprintf
@@ -218,6 +231,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.abort
     libc.src.stdlib.abs
     libc.src.stdlib.aligned_alloc
+    libc.src.stdlib.atexit
     libc.src.stdlib.atof
     libc.src.stdlib.atoi
     libc.src.stdlib.atol
@@ -268,6 +282,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.time.difftime
     libc.src.time.gmtime
     libc.src.time.gmtime_r
+    libc.src.time.localtime
+    libc.src.time.localtime_r
     libc.src.time.mktime
     libc.src.time.strftime
     libc.src.time.strftime_l
@@ -278,6 +294,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.wchar.wcslen
     libc.src.wchar.wctob
 
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
+
     # internal entrypoints
     libc.startup.baremetal.init
     libc.startup.baremetal.fini
@@ -317,8 +336,10 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.fenv.feupdateenv
 
     # math.h entrypoints
+    libc.src.math.acos
     libc.src.math.acosf
     libc.src.math.acoshf
+    libc.src.math.asin
     libc.src.math.asinf
     libc.src.math.asinhf
     libc.src.math.atan2
@@ -754,6 +775,90 @@ if(LIBC_TYPES_HAS_FLOAT128)
   )
 endif()
 
+list(APPEND TARGET_LIBM_ENTRYPOINTS
+  # bfloat16 entrypoints
+  libc.src.math.bf16add
+  libc.src.math.bf16addf
+  libc.src.math.bf16addl
+  libc.src.math.bf16div
+  libc.src.math.bf16divf
+  libc.src.math.bf16divl
+  libc.src.math.bf16fma
+  libc.src.math.bf16fmaf
+  libc.src.math.bf16fmal
+  libc.src.math.bf16mul
+  libc.src.math.bf16mulf
+  libc.src.math.bf16mull
+  libc.src.math.bf16sub
+  libc.src.math.bf16subf
+  libc.src.math.bf16subl
+  libc.src.math.canonicalizebf16
+  libc.src.math.ceilbf16
+  libc.src.math.copysignbf16
+  libc.src.math.fabsbf16
+  libc.src.math.fdimbf16
+  libc.src.math.floorbf16
+  libc.src.math.fmaxbf16
+  libc.src.math.fmaximumbf16
+  libc.src.math.fmaximum_magbf16
+  libc.src.math.fmaximum_mag_numbf16
+  libc.src.math.fmaximum_numbf16
+  libc.src.math.fminbf16
+  libc.src.math.fminimumbf16
+  libc.src.math.fminimum_magbf16
+  libc.src.math.fminimum_mag_numbf16
+  libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
+  libc.src.math.frexpbf16
+  libc.src.math.fromfpbf16
+  libc.src.math.fromfpxbf16
+  libc.src.math.getpayloadbf16
+  libc.src.math.ilogbbf16
+  libc.src.math.iscanonicalbf16
+  libc.src.math.issignalingbf16
+  libc.src.math.ldexpbf16
+  libc.src.math.llogbbf16
+  libc.src.math.llrintbf16
+  libc.src.math.llroundbf16
+  libc.src.math.log_bf16
+  libc.src.math.logbbf16
+  libc.src.math.lrintbf16
+  libc.src.math.lroundbf16
+  libc.src.math.modfbf16
+  libc.src.math.nanbf16
+  libc.src.math.nearbyintbf16
+  libc.src.math.nextafterbf16
+  libc.src.math.nextdownbf16
+  libc.src.math.nexttowardbf16
+  libc.src.math.nextupbf16
+  libc.src.math.remainderbf16
+  libc.src.math.remquobf16
+  libc.src.math.rintbf16
+  libc.src.math.roundbf16
+  libc.src.math.roundevenbf16
+  libc.src.math.scalblnbf16
+  libc.src.math.scalbnbf16
+  libc.src.math.setpayloadbf16
+  libc.src.math.setpayloadsigbf16
+  libc.src.math.sqrtbf16
+  libc.src.math.truncbf16
+  libc.src.math.totalorderbf16
+  libc.src.math.totalordermagbf16
+  libc.src.math.ufromfpbf16
+  libc.src.math.ufromfpxbf16
+)
+
+if(LIBC_TYPES_HAS_FLOAT128)
+  list(APPEND TARGET_LIBM_ENTRYPOINTS
+    # math.h C++23 mixed bfloat16 and _Float128 entrypoints
+    libc.src.math.bf16addf128
+    libc.src.math.bf16divf128
+    libc.src.math.bf16fmaf128
+    libc.src.math.bf16mulf128
+    libc.src.math.bf16subf128
+  )
+endif()
+
 if(LIBC_COMPILER_HAS_FIXED_POINT)
   list(APPEND TARGET_LIBM_ENTRYPOINTS
     # stdfix.h _Fract and _Accum entrypoints

diff --git a/system/lib/llvm-libc/config/baremetal/arm/headers.txt b/system/lib/llvm-libc/config/baremetal/arm/headers.txt
@@ -2,6 +2,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.assert
     libc.include.complex
     libc.include.ctype
+    libc.include.elf
     libc.include.errno
     libc.include.features
     libc.include.fenv
@@ -23,4 +24,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.time
     libc.include.uchar
     libc.include.wchar
+    libc.include.wctype
 )
diff --git a/system/lib/llvm-libc/config/baremetal/config.json b/system/lib/llvm-libc/config/baremetal/config.json
@@ -4,6 +4,11 @@
       "value": "LIBC_ERRNO_MODE_EXTERNAL"
     }
   },
+  "threads": {
+    "LIBC_CONF_THREAD_MODE": {
+      "value": "LIBC_THREAD_MODE_SINGLE"
+    }
+  },
   "printf": {
     "LIBC_CONF_PRINTF_DISABLE_FIXED_POINT": {
       "value": true
@@ -31,7 +36,12 @@
   },
   "math": {
     "LIBC_CONF_MATH_OPTIMIZATIONS": {
-      "value": "(LIBC_MATH_SKIP_ACCURATE_PASS | LIBC_MATH_SMALL_TABLES)"
+      "value": "(LIBC_MATH_SKIP_ACCURATE_PASS | LIBC_MATH_SMALL_TABLES | LIBC_MATH_NO_ERRNO | LIBC_MATH_INTERMEDIATE_COMP_IN_FLOAT)"
+    }
+  },
+  "general": {
+    "LIBC_ADD_NULL_CHECKS": {
+      "value": false
     }
   }
 }