[lmi-commits] [lmi] master 9eae460d 06/10: Support clang

[Greg Chicares]

branch: master
commit 9eae460db82c1c610d699e9cb151503287b016ee
Author: Gregory W. Chicares <gchicares@sbcglobal.net>
Commit: Gregory W. Chicares <gchicares@sbcglobal.net>

    Support clang
    
    Set flags that are sufficient for building nychthemeral tests with
    clang. Many desirable features are not yet implemented, such as
    optimization and warnings.
---
 compiler_clang.make | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

diff --git a/compiler_clang.make b/compiler_clang.make
index 39664381..d027f7eb 100644
--- a/compiler_clang.make
+++ b/compiler_clang.make
@@ -26,3 +26,137 @@ CXX     := clang++
 LD      := clang++
 # For GNU/Linux, $(RC) is never invoked.
 RC      := windres
+
+# GNU tools (or workalikes) for special purposes.
+#
+# For testing physical closure and generating autodependencies, use
+# either GNU tools or closely compatible equivalents such as clang.
+# This obviates figuring out how other toolchains support these needs.
+#
+# Override these definitions to specify GNU tools when using an
+# incompatible toolchain.
+
+GNU_CPP := $(CPP)
+GNU_CXX := $(CXX)
+
+# EXTRA variables.
+#
+# /\w*EXTRA_/ variables such as $(EXTRA_LDFLAGS) are set by other
+# makefiles, and used here without modification.
+
+# C preprocessor flags.
+#
+# wx sets _FILE_OFFSET_BITS to 64; this definition is explicitly
+# repeated below to make assurance doubly sure--see:
+#   https://lists.nongnu.org/archive/html/lmi/2019-03/msg00039.html
+# et seq.
+
+REQUIRED_CPPFLAGS = \
+  $(addprefix -I , $(lmi_include_directories)) \
+  $(addprefix -isystem , $(sys_include_directories)) \
+  $(lmi_wx_new_so_attributes) \
+  $(platform_defines) \
+  $(wx_predefinitions) \
+  -D_FILE_OFFSET_BITS=64 \
+
+ifneq (,$(USE_SO_ATTRIBUTES))
+  REQUIRED_CPPFLAGS += -DLMI_USE_SO_ATTRIBUTES $(lmi_so_attributes)
+endif
+
+ifeq (safestdlib,$(build_type))
+  REQUIRED_CPPFLAGS += \
+    -D_GLIBCXX_DEBUG \
+    -D_GLIBCXX_DEBUG_PEDANTIC \
+    -D_GLIBCXX_SANITIZE_VECTOR \
+
+endif
+
+# Compiler-and-linker flags.
+#
+# 'c_l_flags' are to be used in both compiler and linker commands.
+# The gprof '-pg' flag is one example. Another is '-fPIC', which
+# pc-linux-gnu requires for '-shared':
+#   https://gcc.gnu.org/onlinedocs/gcc/Link-Options.html#DOCF1
+# Yet another is 'debug_flag': the GNU Coding Standards
+#   https://www.gnu.org/prep/standards/html_node/Command-Variables.html
+# suggest including flags such as '-g' in $(CFLAGS) because they
+# are "not required for proper compilation", but lmi supports
+# multiple build types that transcend that "proper" notion.
+
+c_l_flags := $(debug_flag) $(analyzer_flag)
+
+ifeq (x86_64-pc-linux-gnu,$(LMI_TRIPLET))
+  c_l_flags += -fPIC
+endif
+
+# C and C++ compiler flags.
+
+REQUIRED_COMPILER_FLAGS := \
+  $(c_l_flags) \
+  -ffp-model=strict \
+  -fno-ms-compatibility \
+  -fno-ms-extensions \
+
+# C compiler flags.
+
+REQUIRED_CFLAGS = $(REQUIRED_COMPILER_FLAGS) -std=c99
+
+# C++ compiler flags.
+
+REQUIRED_CXXFLAGS = $(REQUIRED_COMPILER_FLAGS) -std=c++20
+
+# Write '-Wno' options at the end, with a rationale here.
+#
+# -Wstring-plus-int: false negatives and no true positives in lmi.
+
+CXXFLAGS = -Wno-string-plus-int
+
+# Linker flags.
+
+REQUIRED_LDFLAGS = \
+  $(c_l_flags) \
+  $(addprefix -L , $(all_library_directories)) \
+  $(EXTRA_LDFLAGS) \
+  $(EXTRA_LIBS) \
+
+LDFLAGS = -Wl,-Map,$@.map \
+
+ifeq (x86_64-pc-linux-gnu,$(LMI_TRIPLET))
+  LDFLAGS += -Wl,-z,relro -Wl,-z,now -Wl,-z,noexecstack -Wl,-z,separate-code
+endif
+
+# Archiver flags.
+
+REQUIRED_ARFLAGS = -rus
+
+# Resource compiler (msw) flags.
+#
+# The '--use-temp-file' windres option seems to be often helpful and
+# never harmful.
+#
+# As seems customary, $(ALL_CPPFLAGS) is passed to 'windres', which
+# doesn't recognize '-isystem'--hence the $(subst) workaround.
+
+REQUIRED_RCFLAGS = \
+  $(subst -isystem,--include-dir,$(ALL_CPPFLAGS)) \
+  --use-temp-file \
+
+# Only these /ALL_[A-Z]*FLAGS/ are both set here and used for targets.
+# This casual command is useful for testing that:
+#   git grep FLAGS workhorse.make| grep -o '\w*FLAGS' | sort -u
+#
+# The GNU Coding Standards
+#   https://www.gnu.org/prep/standards/html_node/Command-Variables.html
+# say
+#   "Put CFLAGS last in the compilation command, after other
+#    variables containing compiler options, so the user can
+#    use CFLAGS to override the others."
+# Going one step beyond that idea, lmi puts $(tutelary_flag) last,
+# after even $(CFLAGS), for flags that must not be overridden.
+
+ALL_CPPFLAGS = $(REQUIRED_CPPFLAGS) $(CPPFLAGS)
+ALL_CFLAGS   = $(REQUIRED_CFLAGS)   $(CFLAGS)   $(tutelary_flag)
+ALL_CXXFLAGS = $(REQUIRED_CXXFLAGS) $(CXXFLAGS) $(tutelary_flag)
+ALL_LDFLAGS  = $(REQUIRED_LDFLAGS)  $(LDFLAGS)
+ALL_ARFLAGS  = $(REQUIRED_ARFLAGS)  $(ARFLAGS)
+ALL_RCFLAGS  = $(REQUIRED_RCFLAGS)  $(RCFLAGS)