HB Improvements: Fix compiler warnings on modern compilers

Resolve warnings when compiling with gcc 4.8. Compiled with GCC 7.3,
no more compile errors/warnings; build ends with caught exception from
linker. This commit compiles with GCC 8.2, no more error/warnings; except
for a linking warning.

Change-Id: Ib5d7c2b5bd350edc76ee2c7de96896154cd44420
RTC: 202716
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/72271
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>
Reviewed-by: Ilya Smirnov <ismirno@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

2 files changed, 38 insertions, 15 deletions

diff --git a/src/build/linker/linker.C b/src/build/linker/linker.C
index 9e4751e41..a9a9d0f5e 100644
--- a/src/build/linker/linker.C
+++ b/src/build/linker/linker.C
@@ -283,6 +283,36 @@ inline void advance_to_page_align(FILE * i_f)
     }
 }
 
+/**
+ * @brief Throw error if std::fread was performed incorrectly.
+ * @param[i] i_buffer: pointer to the first object in the array to be read
+ * @param[i] i_size: size of each object in i_buffer array, in bytes
+ * @param[i] i_count: number of the objects in i_buffer array to be read
+ * @param[i] i_stream: input-file pointer
+ */
+inline void fread_wrapper(void* i_buffer, const size_t i_size,
+        const size_t i_count, FILE* i_stream)
+{
+
+    size_t n_values_read = fread(i_buffer,i_size,i_count,i_stream);
+
+    if (i_count != n_values_read)
+    {
+        if (feof(i_stream))
+        {
+            throw "End of file reached, file not read fully.";
+        }
+        else if (ferror(i_stream))
+        {
+            throw "Error occurred while reading file.";
+        }
+        else
+        {
+            throw "Unknown read error.";
+        }
+    }
+}
+
 //
 // Global variables
 //
@@ -669,7 +699,7 @@ bool Object::write_object()
         long int file_size = ftell(file);
         uint8_t * buffer = new uint8_t[file_size];
         fseek(file,0,SEEK_SET);
-        fread(buffer,file_size,1,file);
+        fread_wrapper(buffer,file_size,1,file);
         fwrite(buffer,file_size,1,iv_output);
         delete [] buffer;
         fclose(file);
@@ -895,7 +925,7 @@ bool Object::perform_local_relocations()
         bool is_weak = false;
 
         fseek(iv_output, offset + i->address, SEEK_SET);
-        fread(data, sizeof(uint64_t), 1, iv_output);
+        fread_wrapper(data, sizeof(uint64_t), 1, iv_output);
 
         if (weak_symbols.find(i->name) != weak_symbols.end())
         {
@@ -1024,7 +1054,8 @@ bool Object::perform_global_relocations()
                         }
 
                         fseek(j->iv_output, symbol_addr, SEEK_SET);
-                        fread(data, sizeof(uint64_t), 3, j->iv_output);
+                        fread_wrapper(data, sizeof(uint64_t), 3,
+                                              j->iv_output);
 
                         fseek(iv_output, offset + i->address, SEEK_SET);
                         fwrite(data, sizeof(uint64_t), 3, iv_output);
@@ -1172,7 +1203,7 @@ void ModuleTable::write_table(vector<Object> & i_objects)
         cout << "Updating base module table..." << endl;
         fseek(iv_output, module_table_offset, SEEK_SET);
         char mx_mod_ch = 0;
-        fread(&mx_mod_ch,sizeof(char),1,iv_output);
+        fread_wrapper(&mx_mod_ch,sizeof(char),1,iv_output);
         max_modules = (uint64_t)mx_mod_ch; // VFS_MODULE_MAX;
         ++i;
     }
diff --git a/src/build/mkrules/cflags.env.mk b/src/build/mkrules/cflags.env.mk
index 732e6559e..04ff6fedd 100644
--- a/src/build/mkrules/cflags.env.mk
+++ b/src/build/mkrules/cflags.env.mk
@@ -38,22 +38,14 @@ CFLAGS += -DNO_INITIALIZER_LIST
 CFLAGS += -D__FAPI
 endif
 
-try = $(shell set -e; if ($(1)) >/dev/null 2>&1; \
-        then echo "$(2)"; \
-        else echo "$(3)"; fi )
-
-try-cflag = $(call try,$(1) $(2) -x c -c /dev/null -o /dev/null,$(2))
-test_cflag = $(call try,$(1) $(2) -x c -c /dev/null -o /dev/null,1,0)
 
 COMMONFLAGS += $(OPT_LEVEL) -nostdlib
 CFLAGS += $(COMMONFLAGS) -mcpu=power7 -nostdinc -g -mno-vsx -mno-altivec\
-          -Wall -mtraceback=no -pipe -mabi=elfv1 \
-          $(call try-cflag,$(CC),-Wno-error=sizeof-array-argument) \
-          $(call try-cflag,$(CC),-Wno-error=unused-function) \
+          -Werror -Wall -mtraceback=no -pipe -mabi=elfv1 \
 	  -ffunction-sections -fdata-sections -ffreestanding -mbig-endian
 ASMFLAGS += $(COMMONFLAGS) -mcpu=power7 -mbig-endian -ffreestanding -mabi=elfv1
-CXXFLAGS += $(CFLAGS) -nostdinc++ -fno-rtti -fno-exceptions -Wall \
-	    -fuse-cxa-atexit -std=gnu++14 -fpermissive
+CXXFLAGS += $(CFLAGS) -nostdinc++ -fno-rtti -fno-exceptions -Werror -Wall \
+	    -fuse-cxa-atexit -std=gnu++14
 LDFLAGS += --nostdlib --sort-common -EB $(COMMONFLAGS)
 
 INCFLAGS = $(addprefix -I, $(INCDIR) )