From ba71e8d5e3fcfa783edb830fefcf08a88f47cd65 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sat, 23 Mar 2024 22:24:45 -0400
Subject: [PATCH] Add support for building object files from LLVM assembly
 sources - close #175

---
 build_tests/llvm/Rsconscript                 |  4 ++++
 build_tests/llvm/direct.rb                   |  8 ++++++++
 build_tests/llvm/main.c                      |  6 ++++++
 build_tests/llvm/main2.c                     |  9 +++++++++
 build_tests/llvm/one.ll                      |  9 +++++++++
 build_tests/llvm/two.ll                      |  9 +++++++++
 lib/rscons.rb                                |  1 +
 lib/rscons/builders/lang/llvm_asm.rb         | 10 ++++++++++
 lib/rscons/default_construction_variables.rb |  5 +++++
 spec/build_tests_spec.rb                     | 18 ++++++++++++++++++
 10 files changed, 79 insertions(+)
 create mode 100644 build_tests/llvm/Rsconscript
 create mode 100644 build_tests/llvm/direct.rb
 create mode 100644 build_tests/llvm/main.c
 create mode 100644 build_tests/llvm/main2.c
 create mode 100644 build_tests/llvm/one.ll
 create mode 100644 build_tests/llvm/two.ll
 create mode 100644 lib/rscons/builders/lang/llvm_asm.rb

diff --git a/build_tests/llvm/Rsconscript b/build_tests/llvm/Rsconscript
new file mode 100644
index 0000000..8782816
--- /dev/null
+++ b/build_tests/llvm/Rsconscript
@@ -0,0 +1,4 @@
+env do |env|
+  env["LLVMAS_FLAGS"] += %w[-Wno-override-module]
+  env.Program("llvmtest.exe", %w[main.c one.ll])
+end
diff --git a/build_tests/llvm/direct.rb b/build_tests/llvm/direct.rb
new file mode 100644
index 0000000..cbd8349
--- /dev/null
+++ b/build_tests/llvm/direct.rb
@@ -0,0 +1,8 @@
+configure do
+  check_c_compiler "clang"
+end
+
+env do |env|
+  env["LLVMAS_FLAGS"] += %w[-Wno-override-module]
+  env.Program("llvmtest.exe", %w[one.ll two.ll main2.c], direct: true)
+end
diff --git a/build_tests/llvm/main.c b/build_tests/llvm/main.c
new file mode 100644
index 0000000..5fae79b
--- /dev/null
+++ b/build_tests/llvm/main.c
@@ -0,0 +1,6 @@
+extern int one(void);
+
+int main(int argc, char * argv[])
+{
+    return one();
+}
diff --git a/build_tests/llvm/main2.c b/build_tests/llvm/main2.c
new file mode 100644
index 0000000..1e6e00d
--- /dev/null
+++ b/build_tests/llvm/main2.c
@@ -0,0 +1,9 @@
+extern int one(void);
+extern int two(void);
+
+int main(int argc, char * argv[])
+{
+    one();
+    two();
+    return 0;
+}
diff --git a/build_tests/llvm/one.ll b/build_tests/llvm/one.ll
new file mode 100644
index 0000000..b67b97f
--- /dev/null
+++ b/build_tests/llvm/one.ll
@@ -0,0 +1,9 @@
+@str = private unnamed_addr constant [12 x i8] c"hello world\00"
+
+declare i32 @puts(ptr nocapture) nounwind
+
+define i32 @one()
+{
+    call i32 @puts(ptr @str)
+    ret i32 0
+}
diff --git a/build_tests/llvm/two.ll b/build_tests/llvm/two.ll
new file mode 100644
index 0000000..b51fd4d
--- /dev/null
+++ b/build_tests/llvm/two.ll
@@ -0,0 +1,9 @@
+@str = private unnamed_addr constant [12 x i8] c"hello again\00"
+
+declare i32 @puts(ptr nocapture) nounwind
+
+define i32 @two()
+{
+    call i32 @puts(ptr @str)
+    ret i32 0
+}
diff --git a/lib/rscons.rb b/lib/rscons.rb
index b0d38b4..9a09e3c 100644
--- a/lib/rscons.rb
+++ b/lib/rscons.rb
@@ -156,6 +156,7 @@ require_relative "rscons/builders/lang/asm"
 require_relative "rscons/builders/lang/c"
 require_relative "rscons/builders/lang/cxx"
 require_relative "rscons/builders/lang/d"
+require_relative "rscons/builders/lang/llvm_asm"
 
 # Unbuffer $stdout
 $stdout.sync = true
diff --git a/lib/rscons/builders/lang/llvm_asm.rb b/lib/rscons/builders/lang/llvm_asm.rb
new file mode 100644
index 0000000..e825473
--- /dev/null
+++ b/lib/rscons/builders/lang/llvm_asm.rb
@@ -0,0 +1,10 @@
+Rscons::Builders::Object.register(
+  command: "${LLVMAS_CMD}",
+  direct_command: "${LLVMAS_CMD:direct}",
+  suffix: "${LLVMAS_SUFFIX}",
+  short_description: "Assembling")
+Rscons::Builders::SharedObject.register(
+  command: "${LLVMAS_CMD}",
+  direct_command: "${LLVMAS_CMD:direct}",
+  suffix: "${LLVMAS_SUFFIX}",
+  short_description: "Assembling")
diff --git a/lib/rscons/default_construction_variables.rb b/lib/rscons/default_construction_variables.rb
index d03159d..aa8aa7a 100644
--- a/lib/rscons/default_construction_variables.rb
+++ b/lib/rscons/default_construction_variables.rb
@@ -58,6 +58,11 @@ module Rscons
     "LIBPATH" => [],
     "LIBS" => [],
     "LIBSUFFIX" => ".a",
+    "LLVMAS" => "clang",
+    "LLVMAS_CMD" => %w[${LLVMAS} -c -o ${_TARGET} ${LLVMAS_FLAGS} ${_SOURCES}],
+    "LLVMAS_CMD:direct" => %w[${LLVMAS} -o ${_TARGET} ${LLVMAS_FLAGS} ${LDFLAGS} ${_SOURCES} ${LIBDIRPREFIX}${LIBPATH} ${LIBLINKPREFIX}${LIBS}],
+    "LLVMAS_FLAGS" => [],
+    "LLVMAS_SUFFIX" => ".ll",
     "OBJDUMP" => "objdump",
     "OBJSUFFIX" => %w[.o],
     "PROGSUFFIX" => on_windows ? ".exe" : "",
diff --git a/spec/build_tests_spec.rb b/spec/build_tests_spec.rb
index 82c3e61..8d592ab 100644
--- a/spec/build_tests_spec.rb
+++ b/spec/build_tests_spec.rb
@@ -3408,4 +3408,22 @@ EOF
     end
   end
 
+  it "supports building LLVM assembly files with the Program builder" do
+    test_dir "llvm"
+    result = run_rscons
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(File.exist?("llvmtest.exe")).to be_truthy
+    expect(`./llvmtest.exe`).to match /hello world/
+  end
+
+  it "supports building LLVM assembly files with the Program builder in direct mode" do
+    test_dir "llvm"
+    result = run_rscons(args: %w[-f direct.rb])
+    expect(result.stderr).to eq ""
+    expect(result.status).to eq 0
+    expect(File.exist?("llvmtest.exe")).to be_truthy
+    expect(`./llvmtest.exe`).to match /hello again/
+  end
+
 end