LLVM_CONFIG llvm_mode fix

3 files changed, 18 insertions, 4 deletions

diff --git a/docs/ChangeLog b/docs/ChangeLog
index 4ea4e4b2..b32253b6 100644
--- a/docs/ChangeLog
+++ b/docs/ChangeLog
@@ -22,6 +22,8 @@ Version ++2.54d (dev):
     add AFL_CUSTOM_MUTATOR_ONLY (that will trigger the previous behaviour)
   - no more unlinking the input file, this way the input file can also be a
     FIFO or disk partition
+  - setting LLVM_CONFIG for llvm_mode will now again switch to the selected
+    llvm version. If you setup is correct.
   - reducing duplicate code in afl-fuzz
   - added "make help"
   - removed compile warnings from python internal stuff
diff --git a/llvm_mode/Makefile b/llvm_mode/Makefile
index ed853d9d..2d35505e 100644
--- a/llvm_mode/Makefile
+++ b/llvm_mode/Makefile
@@ -38,6 +38,7 @@ endif
 LLVMVER  = $(shell $(LLVM_CONFIG) --version)
 LLVM_UNSUPPORTED = $(shell $(LLVM_CONFIG) --version | egrep -q '^[12]|^3\.0|^1[0-9]' && echo 1 || echo 0 )
 LLVM_MAJOR = $(shell $(LLVM_CONFIG) --version | sed 's/\..*//')
+LLVM_BINDIR = $(shell $(LLVM_CONFIG) --bindir)
 
 ifeq "$(LLVM_UNSUPPORTED)" "1"
   $(warn llvm_mode only supports versions 3.8.0 up to 9)
@@ -77,11 +78,18 @@ endif
 # this seems to be busted on some distros, so using the one in $PATH is
 # probably better.
 
-ifeq "$(origin CC)" "default"
-  ifeq "$(shell uname)" "OpenBSD"
-    CC         = $(BIN_PATH)/clang
-    CXX        = $(BIN_PATH)/clang++
+CC         = $(LLVM_BINDIR)/clang
+CXX        = $(LLVM_BINDIR)/clang++
+
+ifeq "$(shell test -e $(CC) || echo 1 )" "1"
+  # llvm-config --bindir is not providing a valid path, so ...
+  ifeq "$(shell test -e "$(BIN_DIR)/clang" && echo 1)" "1"
+    # we found one in the local install directory, lets use these
+    CC         = $(BIN_DIR)/clang
+    CXX        = $(BIN_DIR)/clang++
   else
+    # hope for the best
+    $(warn we have trouble finding clang/clang++ - llvm-config is not helping us)
     CC         = clang
     CXX        = clang++
   endif
diff --git a/llvm_mode/README.md b/llvm_mode/README.md
index c7ef4b45..f196395b 100644
--- a/llvm_mode/README.md
+++ b/llvm_mode/README.md
@@ -41,6 +41,10 @@ In order to leverage this mechanism, you need to have clang installed on your
 system. You should also make sure that the llvm-config tool is in your path
 (or pointed to via LLVM_CONFIG in the environment).
 
+Note that if you have several LLVM versions installed, pointing LLVM_CONFIG
+to the version you want to use will switch compiling to this specific
+version - if you installation is set up correctly :-)
+
 Unfortunately, some systems that do have clang come without llvm-config or the
 LLVM development headers; one example of this is FreeBSD. FreeBSD users will
 also run into problems with clang being built statically and not being able to