[fix] correctly pass environment vars to the RefC compiler

CHANGELOG.md

@@ -44,10 +44,10 @@
 
 #### RefC
 
-* Adds support for `CFLAGS`, `CPPFLAGS`, and `LDFLAGS` to facilitate building on
+* Adds support for `CFLAGS`, `CPPFLAGS`, `LDFLAGS` and `LDLIBS` to facilitate
-  systems with non-standard installation locations of libraries (e.g. GMP).
+  building on systems with non-standard installation locations of libraries
-  Versions of the flags with the `IDRIS2_` prefix can also be used and take
+  (e.g. GMP). Versions of the flags with the `IDRIS2_` prefix can also be used
-  precedence.
+  and take precedence.
 
 #### Chez
 

CONTRIBUTORS

@@ -2,6 +2,7 @@ Thanks to the following for their help and contributions to Idris 2:
 
 Aaron Lebahn
 Abdelhakim Qbaich
+Adam Brouwers-Harries
 Alain Zscheile
 Aleksei Volkov
 Alex Gryzlov

src/Compiler/RefC/CC.idr

@@ -7,6 +7,8 @@ import Core.Directory
 
 import System
 
+import Data.String
+
 %default total
 
 findCC : IO String
@@ -41,6 +43,14 @@ findLDFLAGS
          | Just ldflags => pure ldflags
        pure ""
 
+findLDLIBS : IO String
+findLDLIBS
+  = do Nothing <- getEnv "IDRIS2_LDLIBS"
+         | Just ldlibs => pure ldlibs
+       Nothing <- getEnv "LDLIBS"
+         | Just ldlibs => pure ldlibs
+       pure ""
+
 clibdirs : List String -> List String
 clibdirs ds = map (\d => "-L" ++ d) ds
 
@@ -68,6 +78,8 @@ compileCObjectFile {asLibrary} sourceFile objectFile =
               "-o", objectFile,
               "-I" ++ refcDir,
               "-I" ++ cDir]
+              ++ (words cppFlags)
+              ++ (words cFlags)
 
      log "compiler.refc.cc" 10 runccobj
      0 <- coreLift $ system runccobj
@@ -85,6 +97,7 @@ compileCFile {asShared} objectFile outFile =
   do cc <- coreLift findCC
      cFlags <- coreLift findCFLAGS
      ldFlags <- coreLift findLDFLAGS
+     ldLibs <- coreLift findLDLIBS
 
      dirs <- getDirs
      refcDir <- findDataFile "refc"
@@ -100,6 +113,9 @@ compileCFile {asShared} objectFile outFile =
               "-L" ++ refcDir
               ] ++ clibdirs (lib_dirs dirs) ++ [
               "-lgmp", "-lm"]
+              ++ (words cFlags)
+              ++ (words ldFlags)
+              ++ (words ldLibs)
 
      log "compiler.refc.cc" 10 runcc
      0 <- coreLift $ system runcc

src/Idris/Env.idr

@@ -38,10 +38,12 @@ envs = [
     MkEnvDesc "IDRIS2_CFLAGS"        "RefC backend: C compiler flags.",
     MkEnvDesc "IDRIS2_CPPFLAGS"      "RefC backend: C preprocessor flags.",
     MkEnvDesc "IDRIS2_LDFLAGS"       "RefC backend: C linker flags.",
+    MkEnvDesc "IDRIS2_LDLIBS"        "RefC backend: C linker library names or flags.",
     MkEnvDesc "CC"                   "RefC backend: C compiler executable (IDRIS2_CC takes precedence).",
     MkEnvDesc "CFLAGS"               "RefC backend: C compiler flags (IDRIS2_CFLAGS takes precedence).",
     MkEnvDesc "CPPFLAGS"             "RefC backend: C preprocessor flags (IDRIS2_CPPFLAGS takes precedence).",
     MkEnvDesc "LDFLAGS"              "RefC backend: C linker flags (IDRIS2_LDFLAGS takes precedence).",
+    MkEnvDesc "LDLIBS"               "RefC backend: C linker library names or flags (IDRIS2_LDLIBS takes precedence).",
     MkEnvDesc "NODE"                 "NodeJS backend: NodeJS executable.",
     MkEnvDesc "PATH"                 "PATH variable is used to search for executables in certain codegens.",
     MkEnvDesc "NO_COLOR"             "Instruct Idris not to print color to stdout. Passing the --color/--colour option will supersede this env var."]

tests/refc/ccompilerArgs/Main.idr

@@ -0,0 +1,15 @@
+import System.FFI
+
+libexternal : String -> String
+libexternal fn = "C:" ++ fn ++ ",libexternalc,externalc.h"
+
+%foreign (libexternal "add")
+add : Int -> Int -> Int
+
+%foreign (libexternal "fastfibsum")
+fastfibsum : Int -> Int
+
+main : IO ()
+main = do
+    printLn $ show (add 50 23)
+    printLn $ show ([fastfibsum x | x <- [0..10]])

tests/refc/ccompilerArgs/expected

@@ -0,0 +1,2 @@
+"73"
+"[0, 1, 2, 4, 7, 12, 20, 33, 54, 88, 143]"

tests/refc/ccompilerArgs/library/Makefile

@@ -0,0 +1,10 @@
+all: libexternalc.so
+
+externalc.o: externalc.c externalc.h
+	cc -c -fPIC $< -o $@
+
+libexternalc.so: externalc.o
+	cc $< -shared -o $@
+
+clean:
+	rm -f externalc.o externalc.so

tests/refc/ccompilerArgs/library/externalc.c

@@ -0,0 +1,20 @@
+#include "externalc.h"
+
+int add(int x, int y) {
+    return x+y;
+}
+
+int fastfibsum(int x) {
+    int acc = 0;
+    int p = 0;
+    int c = 1;
+    int tmp;
+    for (;0 <=-- x;)
+    {
+        acc += c;
+        tmp = c;
+        c = c + p;
+        p = tmp;
+    }
+    return acc;
+}

tests/refc/ccompilerArgs/library/externalc.h

@@ -0,0 +1,3 @@
+int add(int x, int y);
+
+int fastfibsum(int x);

tests/refc/ccompilerArgs/run

@@ -0,0 +1,30 @@
+. ../../testutils.sh
+
+# This test checks to make sure that Idris2's command line handling for the RefC backend is correct.
+# It checks that:
+#   1) Idris2 correctly finds `CFLAGS` and `LDFLAGS` in the environment,
+#   2) The values in `CFLAGS` and `LDFLAGS` are separated correctly to be passed to the compiler
+#
+# (1) is achieved by compiling a c library (`externalc`) in a separate folder, and then explicitly
+# pointing the compiler to the header files (with `-I./library/`) and shared library (with `-L./library`)
+# and requesting that libexternalc.{so,dylib,dll} is linked (with `-lexternalc`). We additionally point the
+# dynamic library loader to the correct location with `DYLD_LIBRARY_PATH`.
+#
+# (2) is achieved by passing multiple options, separated by spaces, in each of `CFLAGS` and `LDFLAGS`.
+# These options are `-O3` for the c flags, and `-Wl,-pie` for the linker flags. They do not change the
+# semantics of the resulting code (`-O3` simply optimises it more, and `-Wl,-pie` emits position
+# independent code in the final executable), but do check that we correctly split up the environment
+# variables when we pass them to the C compiler.
+
+cd ./library/
+    make > /dev/null
+cd ..
+
+export CFLAGS="-I./library/ -O3"
+export LDFLAGS="-L./library/ -Wl,-pie"
+export LDLIBS="-lexternalc"
+export DYLD_LIBRARY_PATH="./library/"
+
+idris2 --cg refc -o cffi Main.idr > /dev/null
+
+./build/exec/cffi