[libc][cmake] make i386 distinct from x86_64 (llvm#114477)

Configured via:

    $ cmake ../runtimes -G Ninja -DLLVM_ENABLE_LLD=ON \
      -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_RUNTIMES="libc" \
      -DLIBC_TARGET_TRIPLE=i386-linux-gnu -DCMAKE_C_COMPILER=clang \
      -DCMAKE_CXX_COMPILER=clang++

Link: llvm#93709

Author: nickdesaulniers

libc/cmake/modules/LLVMLibCArchitectures.cmake

@@ -39,8 +39,10 @@ function(get_arch_and_system_from_triple triple arch_var sys_var)
     set(target_arch "arm")
   elseif(target_arch MATCHES "^aarch64")
     set(target_arch "aarch64")
-  elseif(target_arch MATCHES "(x86_64)|(AMD64|amd64)|(^i.86$)")
+  elseif(target_arch MATCHES "(x86_64)|(AMD64|amd64)")
     set(target_arch "x86_64")
+  elseif(target_arch MATCHES "(^i.86$)")
+    set(target_arch "i386")
   elseif(target_arch MATCHES "^(powerpc|ppc)")
     set(target_arch "power")
   elseif(target_arch MATCHES "^riscv32")
@@ -147,6 +149,8 @@ if(LIBC_TARGET_ARCHITECTURE STREQUAL "arm")
 elseif(LIBC_TARGET_ARCHITECTURE STREQUAL "aarch64")
   set(LIBC_TARGET_ARCHITECTURE_IS_AARCH64 TRUE)
 elseif(LIBC_TARGET_ARCHITECTURE STREQUAL "x86_64")
+  set(LIBC_TARGET_ARCHITECTURE_IS_X86_64 TRUE)
+elseif(LIBC_TARGET_ARCHITECTURE STREQUAL "i386")
   set(LIBC_TARGET_ARCHITECTURE_IS_X86 TRUE)
 elseif(LIBC_TARGET_ARCHITECTURE STREQUAL "riscv64")
   set(LIBC_TARGET_ARCHITECTURE_IS_RISCV64 TRUE)

libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake

@@ -5,10 +5,10 @@
 # Initialize ALL_CPU_FEATURES as empty list.
 set(ALL_CPU_FEATURES "")
 
-if(${LIBC_TARGET_ARCHITECTURE_IS_X86})
+if(LIBC_TARGET_ARCHITECTURE_IS_X86_64)
   set(ALL_CPU_FEATURES SSE2 SSE4_2 AVX AVX2 AVX512F AVX512BW FMA)
   set(LIBC_COMPILE_OPTIONS_NATIVE -march=native)
-elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
+elseif(LIBC_TARGET_ARCHITECTURE_IS_AARCH64)
   set(ALL_CPU_FEATURES "FullFP16")
   set(LIBC_COMPILE_OPTIONS_NATIVE -mcpu=native)
 endif()

libc/cmake/modules/LLVMLibCCompileOptionRules.cmake

@@ -10,15 +10,15 @@ function(_get_compile_options_from_flags output_var)
 
   if(LLVM_COMPILER_IS_GCC_COMPATIBLE)
     if(ADD_FMA_FLAG)
-      if(LIBC_TARGET_ARCHITECTURE_IS_X86)
+      if(LIBC_TARGET_ARCHITECTURE_IS_X86_64)
         list(APPEND compile_options "-mavx2")
         list(APPEND compile_options "-mfma")
       elseif(LIBC_TARGET_ARCHITECTURE_IS_RISCV64)
         list(APPEND compile_options "-D__LIBC_RISCV_USE_FMA")
       endif()
     endif()
     if(ADD_ROUND_OPT_FLAG)
-      if(LIBC_TARGET_ARCHITECTURE_IS_X86)
+      if(LIBC_TARGET_ARCHITECTURE_IS_X86_64)
         # ROUND_OPT_FLAG is only enabled if SSE4.2 is detected, not just SSE4.1,
         # because there was code to check for SSE4.2 already, and few CPUs only
         # have SSE4.1.
@@ -145,7 +145,7 @@ function(_get_common_compile_options output_var flags)
     endif()
     if (LIBC_CONF_KEEP_FRAME_POINTER)
       list(APPEND compile_options "-fno-omit-frame-pointer")
-      if (LIBC_TARGET_ARCHITECTURE_IS_X86)
+      if (LIBC_TARGET_ARCHITECTURE_IS_X86_64)
         list(APPEND compile_options "-mno-omit-leaf-frame-pointer")
       endif()
     endif()

libc/cmake/modules/LLVMLibCFlagRules.cmake

@@ -268,21 +268,21 @@ set(EXPLICIT_SIMD_OPT_FLAG "EXPLICIT_SIMD_OPT")
 set(MISC_MATH_BASIC_OPS_OPT_FLAG "MISC_MATH_BASIC_OPS_OPT")
 
 # Skip FMA_OPT flag for targets that don't support fma.
-if(NOT((LIBC_TARGET_ARCHITECTURE_IS_X86 AND (LIBC_CPU_FEATURES MATCHES "FMA")) OR
+if(NOT((LIBC_TARGET_ARCHITECTURE_IS_X86_64 AND (LIBC_CPU_FEATURES MATCHES "FMA")) OR
        LIBC_TARGET_ARCHITECTURE_IS_RISCV64))
   set(SKIP_FLAG_EXPANSION_FMA_OPT TRUE)
 endif()
 
 # Skip EXPLICIT_SIMD_OPT flag for targets that don't support SSE2.
 # Note: one may want to revisit it if they want to control other explicit SIMD
-if(NOT(LIBC_TARGET_ARCHITECTURE_IS_X86 AND (LIBC_CPU_FEATURES MATCHES "SSE2")))
+if(NOT(LIBC_TARGET_ARCHITECTURE_IS_X86_64 AND (LIBC_CPU_FEATURES MATCHES "SSE2")))
   set(SKIP_FLAG_EXPANSION_EXPLICIT_SIMD_OPT TRUE)
 endif()
 
 # Skip ROUND_OPT flag for targets that don't support rounding instructions. On
 # x86, these are SSE4.1 instructions, but we already had code to check for
 # SSE4.2 support.
-if(NOT((LIBC_TARGET_ARCHITECTURE_IS_X86 AND (LIBC_CPU_FEATURES MATCHES "SSE4_2")) OR
+if(NOT((LIBC_TARGET_ARCHITECTURE_IS_X86_64 AND (LIBC_CPU_FEATURES MATCHES "SSE4_2")) OR
        LIBC_TARGET_ARCHITECTURE_IS_AARCH64 OR LIBC_TARGET_OS_IS_GPU))
   set(SKIP_FLAG_EXPANSION_ROUND_OPT TRUE)
 endif()

libc/cmake/modules/LLVMLibCTestRules.cmake

@@ -402,7 +402,7 @@ function(add_integration_test test_name)
   if(NOT INTEGRATION_TEST_SRCS)
     message(FATAL_ERROR "The SRCS list for add_integration_test is missing.")
   endif()
-  if(NOT TARGET libc.startup.${LIBC_TARGET_OS}.crt1)
+  if(NOT LLVM_LIBC_FULL_BUILD AND NOT TARGET libc.startup.${LIBC_TARGET_OS}.crt1)
     message(FATAL_ERROR "The 'crt1' target for the integration test is missing.")
   endif()
 

libc/config/linux/i386/entrypoints.txt

@@ -0,0 +1,11 @@
+set(TARGET_LIBC_ENTRYPOINTS
+  # errno.h entrypoints
+  libc.src.errno.errno
+)
+
+set(TARGET_LIBM_ENTRYPOINTS "")
+
+set(TARGET_LLVMLIBC_ENTRYPOINTS
+  ${TARGET_LIBC_ENTRYPOINTS}
+  ${TARGET_LIBM_ENTRYPOINTS}
+)

libc/config/linux/i386/headers.txt

@@ -0,0 +1,3 @@
+set(TARGET_PUBLIC_HEADERS
+  libc.include.assert
+)

libc/src/__support/OSUtil/linux/i386/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_header_library(
+  linux_i386_util
+  HDRS
+    syscall.h
+)
+
+add_header_library(
+  vdso
+  HDRS
+    vdso.h
+)